Tankless water heaters a joke

beaglebuddyJanuary 16, 2006

Who else thinks these are a bad idea ?

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Have you actual experience with this type heater or are you expressing an opinion formed for reasons other than experience?

    Bookmark   January 16, 2006 at 2:47PM
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Yes, I have one in my house unfortunately

    Bookmark   January 16, 2006 at 2:53PM
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They are great, but you need to match the appliance to the application. Buy the right size and install it correctly and you should have no problems.

    Bookmark   January 16, 2006 at 5:02PM
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beaglebuddy, I have an electric tankless that works very well and is perfect for my needs. What are the troubles or dissatisfications that you're having?

    Bookmark   January 16, 2006 at 5:35PM
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Here is a post I made a while back on another column. I am against tankless, ever heard the slogan K.I.S.S. keep it simple stupid, I live by this. Conventional storage heaters have to be amongst the greatest inventions ever. They work without the benefit of electricity, have no moving parts, no p.c. boards to burn out, sensors to lime up, impellers to wear out ect... and no parts to be backordered on a slow boat from china, and they are extremely reliable.With tankless you will need a new oversized flue,probably a larger gas line and you won't have the flow capacity, sure you can make hot water forever but only at a reduced flow rate, so forget about 2 people taking a shower at the same time, yeah you can get a big tankless that has the flow rate but they can cost maybe $2000.00 I think and forget about a recirculating system unless you want a complicated system of pumps, sensors and maybe a small tank How much do you spend on hot water a month ? $20 to $50 bucks maybe, tankless could save you 10-20 percent so you save 10 dollars a month maybe, it's gonna cost $1000.00 or more to go tankless maybe you break even after 10 years but have one malfunction and it's gonna take away any savings possible and your odds of a break down are signifigantly higher.Flush your storage heater every 6 months and it will last forever.Or consider solar hot water this is a source of FREE energyI am against tankless, ever heard the slogan K.I.S.S. keep it simple stupid, I live by this. Conventional storage heaters have to be amongst the greatest inventions ever. They work without the benefit of electricity, have no moving parts, no p.c. boards to burn out, sensors to lime up, impellers to wear out ect... and no parts to be backordered on a slow boat from china, and they are extremely reliable.With tankless you will need a new oversized flue,probably a larger gas line and you won't have the flow capacity, sure you can make hot water forever but only at a reduced flow rate, so forget about 2 people taking a shower at the same time, yeah you can get a big tankless that has the flow rate but they can cost maybe $2000.00 I think and forget about a recirculating system unless you want a complicated system of pumps, sensors and maybe a small tank How much do you spend on hot water a month ? $20 to $50 bucks maybe, tankless could save you 10-20 percent so you save 10 dollars a month maybe, it's gonna cost $1000.00 or more to go tankless maybe you break even after 10 years but have one malfunction and it's gonna take away any savings possible and your odds of a break down are signifigantly higher.Flush your storage heater every 6 months and it will last forever.Or consider solar hot water this is a source of FREE energyI am against tankless, ever heard the slogan K.I.S.S. keep it simple stupid, I live by this. Conventional storage heaters have to be amongst the greatest inventions ever. They work without the benefit of electricity, have no moving parts, no p.c. boards to burn out, sensors to lime up, impellers to wear out ect... and no parts to be backordered on a slow boat from china, and they are extremely reliable.With tankless you will need a new oversized flue,probably a larger gas line and you won't have the flow capacity, sure you can make hot water forever but only at a reduced flow rate, so forget about 2 people taking a shower at the same time, yeah you can get a big tankless that has the flow rate but they can cost maybe $2000.00 I think and forget about a recirculating system unless you want a complicated system of pumps, sensors and maybe a small tank How much do you spend on hot water a month ? $20 to $50 bucks maybe, tankless could save you 10-20 percent so you save 10 dollars a month maybe, it's gonna cost $1000.00 or more to go tankless maybe you break even after 10 years but have one malfunction and it's gonna take away any savings possible and your odds of a break down are signifigantly higher.Flush your storage heater every 6 months and it will last forever.Or consider solar hot water this is a source of FREE energyI am against tankless, ever heard the slogan K.I.S.S. keep it simple stupid, I live by this. Conventional storage heaters have to be amongst the greatest inventions ever. They work without the benefit of electricity, have no moving parts, no p.c. boards to burn out, sensors to lime up, impellers to wear out ect... and no parts to be backordered on a slow boat from china, and they are extremely reliable.With tankless you will need a new oversized flue,probably a larger gas line and you won't have the flow capacity, sure you can make hot water forever but only at a reduced flow rate, so forget about 2 people taking a shower at the same time, yeah you can get a big tankless that has the flow rate but they can cost maybe $2000.00 I think and forget about a recirculating system unless you want a complicated system of pumps, sensors and maybe a small tank How much do you spend on hot water a month ? $20 to $50 bucks maybe, tankless could save you 10-20 percent so you save 10 dollars a month maybe, it's gonna cost $1000.00 or more to go tankless maybe you break even after 10 years but have one malfunction and it's gonna take away any savings possible and your odds of a break down are signifigantly higher.Flush your storage heater every 6 months and it will last forever.Or consider solar hot water this is a source of FREE energy

    Bookmark   January 16, 2006 at 6:50PM
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Nice paragraph, but it repeats the same thing four times. That's not very simple, LOL.

And doesn't specifically answer the question of what trouble you are having.

I've not yet run across an electric conventional water heater that doesn't require electricity to work. A gas water heater, of course, one may not require electricity.

Like any product, tankless is appropriate for some people and not for others.

    Bookmark   January 16, 2006 at 7:51PM
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Most everyone around here uses gas. Now it's hooked up to a Rube Goldberg system of pumps and sensors to get the flow rate,Its a aquastar 125 and there was a real problem getting a consistent temp out of a single handle valve. Temp is flow sensetive so when it's too cold and you turn faucet handle hotter you are also changing the temp of water coming out of heater but you don't realize it until 20 seconds later because the heater is far from tap. I know some newer types use a different system but there are other problems. Where is the savings ?

    Bookmark   January 16, 2006 at 8:07PM
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The savings for me comes from setting my electric tankless at 105°F in winter and 102°F in summer, which is perfect for showering. It could handle three simultaneous showers at that temp. Why the hell OVERHEAT the water to 120°F or higher for a shower and temper it by adding cold? That's like flooring the accelerator on your car when driving through a residential area and achieving 30 MPH by holding the brake. Senseless. (That could be part of your problem, trying to achieve and maintain too high of a temperature, which is harder to do at varying flow rages, probably more so for gas than electric.)

Depending on the usage location, it may take a couple mins for the temperature to get up to the mark after a hot tap is turned on, but once that is settled changing the flow rate does not affect the temperature. It's quite consistent. Apparently electric can handle varying flow rates better than gas, and also takes a lower GPM to activate and stay activated. I have friends who have a Bosch Aquastar and I've heard them say one particular shower in the house is difficult with consistent temp.

The closest usage point is my washer, heated water arrives in about 30 seconds. The furthest usage point is my master bath, which is 65 feet as the crow flies (could be longer as the pipes run) and takes about four minutes at the approx .5 to .7 GPM flow rate that I used to get a shower started (note I said started, I turn it up of course after I step in).

I don't raise the temp for dishwashing because my dishwasher has built-in water heating to as high as 163°F.

I do raise it for clothes washing, to 115°F which is what my washer "wants" for a warm wash (or to 130°F or 140°F maybe once every two weeks for whites). My washer uses only about 5 gallons of heated water per average load.

I don't dispute that you are unhappy with tankless. Whether that's because of your usage habits, characteristics of your gas unit, or design of your plumbing, there's no way for me to know. But you saying that tankless is a joke is wrong, because not everybody has your dissatisfaction with them.

    Bookmark   January 16, 2006 at 10:28PM
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I am considering a SETS electric tankless water heater for our being-constructed new house. The Mrs. absolutely wants to be able to have 2 fixtures running at the same time. I emailed the SETS company, and they replied to add a small storage tank after their unit. Essentially, it acts as a capacitor in an electric circuit, storing water to allow a bigger dump load but minimizing the storage losses and waste energy in overheating water.

I've spec'd one electric storage type water heater for the new house. Electricity here is cheap (hydro power), and actually our POCO reports it costs more in operating costs for a gas storage type water heater than electric at current prices. If we find we're running out of hot water, I'll install a SETS tankless unit ahead of the tank, to preheat the water going into the tank, increasing the volume of water it takes to dilute the tank with cold incoming well water.

I've also read that gas tankless units aren't as accurate in maintaining temps. As others have said, I think tankless like anything can be good for some and not for others.

    Bookmark   January 16, 2006 at 10:41PM
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Jayhitch, you haven't lived with tankless yet. I thought they were a great idea to until I got one. Dadoes I can get hot water from any tap in about 2 seconds try doing that tankless. 4 minutes ! essentially I am not on tankless now as the aquastar is acting as a boiler, but if I had to do it all over again I'd just get a storage tank type heater.The cost of all this could never equal any energy savings from tankless and what about all the water wasted waiting for it to get hot.

    Bookmark   January 16, 2006 at 11:22PM
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Yes, I know 4 mins for heated water to a shower is awful, but it has nothing to do with the tankless and everything to do with there being only one water heater for the entire house. The distance and delay would be the same if there was a conventional water heater installed where the tankless resides.

I don't need hot water from a tap in 2 seconds. I'm not in that much of a hurry. The water "wasted" ends up sprinkled on my yard, so it isn't really wasted.

Just for fun, and I know it isn't relevant to anything ... what do you think my electric bill / KWH used (I don't have any gas) should be for a 2,550 sq ft house for the month of December, with two refrigerators, several days of 30-degree weather (although this is in south Texas), and a weekend of house guests that involved extra showers, a little extra cooking, and about 8 to 10 extra loads of clothes washed and dried (in addition to what I normally do)? Oh, and there were also some Christmas lights during the month. And a computer running 24/7. Water well, septic system. Garage door opener. Lots of stand-by consumption from audio/video equipment. And other miscellaneous things.

    Bookmark   January 17, 2006 at 12:01AM
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The point is w/ storage tank you can have a simple recirc. system on a timer and get instant hot water. Tank costs $300 and pump costs $120 how much did your tankless cost ? sorry I couldn't even venture on your elec. bill we have just two people in a warm climate and use gas for all cooking & heating

    Bookmark   January 17, 2006 at 12:51AM
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Honestly, I don't know how much the tankless unit cost. I didn't make the specific selection, it was already installed in the 9-month-old house I bought.

Come on, you can make a guess. Surely you know some people who are all-electric. Or take your electric, convert your cooking & heating dollars to electric, and estimate it against what you know about me.

If I didn't use any hot water for a month, it wouldn't cost me anything except the slightest trickle for the electronic control panel. There are no stand-by losses, no pilot lights.

BTW, there are recirculation pumps that work on tankless systems ... surprise, by way of a timer and thermostat that senses when a temperature rise reaches the pump at which point it shuts off. I've considered getting one, just because of that long run to my master bath ... but I've not found it to be a necessity. Really. I don't need hot water in 2 seconds.

Sounds to me like you didn't research tankless very well, or more likely are unwilling to adjust your hot water usage habits to get effective results from it and instead spent extra money on the storage tank and recirculation pump. That's unfortunate.

And my point again is that just because something doesn't meet your needs doesn't mean it isn't appropriate for someone else.

    Bookmark   January 17, 2006 at 2:43AM
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Hey beegle,

>> Now it's hooked up to a Rube Goldberg system of pumps and sensors to get the flow rate,Its a aquastar 125 and there was a real problem getting a consistent temp out of a single handle valve. Those Aquastars and Bosch units are really point-of-use appliances. You should look into the REAL whole house units from Rinnai, Takagi, Noritz etc (Siesco for electric) depending on the fixture and incoming water temps you could easily have 2 showers going.


    Bookmark   January 17, 2006 at 9:40AM
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Dadoes, those pumps won't work w/ tankless as tankless needs a certain minimal flow rate to activate burner and those little recirc pumps don't even come close. Using my tankless as a boiler now I have to use a $300 pump to shoot enough water thru the tankless to get it to turn on. Re; your elect. bill, we use about $20-$25 a month gas in the summer when gas is only for hot water, well cooking also but that can't be much. Let me clarify, we have several homes, the tankless is on propane so it's hard to tell exactly how much is being used per month. Conventional gas storage type heater is on natural gas and we get a bill every month. Tank house gets most of the usage as tankless is more of a weekend home. If I didn't use any hot water I would just turn down temp and get billed only for pilot, maybe $5 a month. But of course we do use hot water so that is a mute point for me.
Good point diveguy1 but those whole house units are very expensive, up to $2000.00 or more and you could never recoup your savings after oversizing gas and flue. And you still couldn't have a recirc system.
Jay Haitch, If you are going to install a storage tank after tankless why get a tankless ? storage tank will still have to run to keep water in tank hot. All elect. hot water is generated at the same efficiency, a tankless will just save on standby loss but if you are going to have a tank aswell what is the point ? If you think you will need more hot water just get a big tank and insulate it better. You are about to spend a bunch of money on 1 or 2 tankless that you will never recoup on elect. bill.

    Bookmark   January 17, 2006 at 1:18PM
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beaglebuddy, I know tankless requires a certain minimal flow rate to activate. I *have* a tankless, so I'm well-aware of that. What's my required flow-rate? The specs for the unit state 0.4 GPM, but I think it's less. I know once it gets going it'll stay going at less than that.

And you keep overlooking the fact that tankless is intended to produce water an an output temp appropriate for the use. It's not necessary to set the temp at 130F to get usable capacity as with a tank. If I want 105°F for a shower, that's what I set, and I don't pay any more than what it takes to get that temp.

My hot water costs are not even $20/month far as I can figure. I can take a 15-min shower @ 105°F for as little as $0.07 (at summer input temps my tankless runs at about 12% of capacity at shower flow rates). I washed a load of whites a couple days ago at 140°F. That cost about $0.04 per minute for whatever was the duration of the washer's fill, which I estimate was around 4 to 5 mins. I don't have to heat up 40 or 60 or 80 gallons of water to that temp ahead of time, I'm only heating and paying for the amount of water the machine needs. I'd have to wash 87 loads of clothes at that temperature in a month to hit $25.

Again, it's unfortunate that tankless water heating doesn't fit your needs. But you simply cannot make a blanket statement that they are a "joke."

    Bookmark   January 17, 2006 at 4:28PM
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If you think this recirc pump is going to turn on your tankless because it pumps the required gpm you are wrong there is a difference between an open tap letting out .4 gpm and a pump that is rated for .4gpm it has to do with head pressure. You would be shocked at the size of the pump it takes to activate in a closed loop. o.k. you spend about the same for h/w that I do, or maybe $5 a month less, but your system cost much more, and you have to wait up to 4 minutes to get h/w and your system has more moving parts and is more likely to break down. As a plumbing contractor I get asked all the time about these, we even installed some at great expense only to have them ask us to remove it later.

    Bookmark   January 17, 2006 at 4:47PM
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It takes 4 minutes to get heated water at my master bath because I run the faucet at only ~0.6 GPM to get it started. So if I replaced my tankless unit with a conventional water heater, it will magically shorten the distance to my master bath?

A recirculation pump is a moot (not mute, as you say) point because I don't have a pressing need to get one.

30 showers @ $0.07. Or how's about double it to $0.14 to be generous. That's $4.20. Maybe 12 loads of clothes per month, even figured at $0.25 (which it's not) is $3.00. Dishwasher about twice per week, I haven't figured what is that, but it ain't much -- 5 fills per load of 0.8 gals each @ 105°F. Be real generous, $3.00 for washing dishes.

That comes to $10.20.

Keep the change.

    Bookmark   January 17, 2006 at 7:49PM
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Wow, you saved ten bucks a month don't spend it all in one place. A whopping $120.00 a year. But it's still a net loss because your system costs more than mine. It will take many years for you to break even and start to save every month let's hope you don't have a breakdown or there goes any chance of breaking even. Perhaps you can count your pennies as you wait for the hot water.
jayhaitch could you please explain the benefit of your system ?

    Bookmark   January 17, 2006 at 10:08PM
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OK fine.

Tankless water heaters are a joke to which
no sane person would subject himself..

Moving on.

    Bookmark   January 17, 2006 at 11:41PM
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beaglebuddy: I didn't want to bore everyone with all my hot water details, but since you asked......;) I spec'd a Marathon 105 gal 4.5Kw electric tank. Why? Lifetime guarantee to original owner, no metal so no anode rod to replace, we're having a softener on a well/septic system and salt type softeners deplete anode rods even faster, so I really don't want a regular steel water tank. Since I decided on the Marathon, they are a lot more expensive anyway, but capital vs operating cost. I'd rather pay up front. The Marathon tank is only a little cheaper than the SETS unit I'm interested in. Yes, the wiring is more, but the new place has 400amp service, and I can do the wiring myself.

My builder says the 105 gal tank is not available here. Hmmm. I'm still investigating, but weighing my options. If we can only get a 75 gal tank, and it's not enough, then my choices are two 75 gal tanks in parallel, a smaller Marathon tank in series, or a tankless as a booster. Our well water here varies between 43-64 F winter/summer, so the water heater will always be heating rather cold water. I'd rather have a tankless high capacity booster to preheat the water, as it can provide even more than another tank, endlessly, unless we've got 2 high flow fixtures going for a long time, which we won't. And why should I potentially have 150gal of water being heated all the time, just so we can fill a jacuzzi and run the wash at the same time? The tankless booster still provides no standby loss and no 75% capacity limit.

These are my reasons, and I'm stickin' to them, officer...:)

    Bookmark   January 17, 2006 at 11:48PM
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Been there tried that, here is the problem I see, the tankless would be a bottleneck in the system. All the T/L I have seen will only allow a certain amount of water to flow thru them, not just the pipe size but there is some sort of flow restrictor. W/O T/L you would have almost unlimited flow rate as this set up would probably use 1" pipe on the hot w/ 1" nipples on W/H. Now here is a good use for a T/L, one of the only I can think of, plumb the T/L to supply only the jacuzzi. Just trying to help others from making the same mistakes I did

    Bookmark   January 18, 2006 at 12:35AM
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Just did a little googling on SETS, has 3/4 " fittings and they apear to be even weaker than the gas units

    Bookmark   January 18, 2006 at 12:43AM
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Here is an article that discusses tankless water heaters. The author discusses specifically and mathematically why he is not in favor of them, and also includes other's feedback.

    Bookmark   January 18, 2006 at 11:33AM
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Exellent article akchicago, the author makes many of the points I am trying to make and carries out the math equations. Everyone should read that link. My bigger problem w/T/L is the inability to have a recirc. And you are adding electronics to an appliance that doesn't normally have that. On forced air furnaces I see P.C. boards burn out all the time. There is a huge marketing campaign going on for these and people who are building or remodling think they would be great, I am just trying to inform people of the big picture. In other countries that are not as nice as ours T/L are used on every fixture ( point of use ) these large ones are being made for the American market. The one application where they would make sense would be as a point of use for a jacuzzi tub, then the tank type heater could be made smaller and you could still fill the tub.

    Bookmark   January 18, 2006 at 12:32PM
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I hadn't intended to post any more in this thread, but I want to respond to some points in the linked article. It says the typical temperature for a shower is 115°F to 120°F. Really? Is that really the temperature of the water under which the individual is standing for minutes at a time? Get a thermometer of some ilk, perhaps a kitchen instant-read jobbie, and check the actual water temp (after adjusting the faucet mix) the next time you take a shower. Is it 120°F?

Or turn on your kitchen faucet and adjust the temp to 120°F to see how it feels. Keep in mind that 120°F water cascading over your body in a shower will feel hotter than it does running over your hand at the faucet. 105°F coming out of my kitchen faucet feels just lukewarm on my hand, but it's perfectly fine in the shower.

Is this perhaps a mental thing? I must have the hot water temp set to 120°F (or 125°F or 130°F or whatever) because otherwise there's no way I can get a hot-enough bath when I (must) mix in the cold water. Or, I must set the hot water high so I can turn down the hot water faucet and use less hot water when taking a shower.

I found this info on a search --
Temperature of Water vs. Time to Cause a Bad Burn
150°F (66°C) 2 seconds
140°F (60°C) 6 seconds
125°F (52°C) 2 minutes
120°F (49°C) 10 minutes

And another --
Even if the temperature is 120 degrees, a five minute exposure could result in third-degree burns.

I realize everyone is different, and some people may very well thrive with a 120°F shower. Personally, I find that 105°F is plenty warm for a shower. I had a shower this morning. Out of curiousity, I set the water running, then went to check the display on my tankless. Among other parameters, it can report instantaneous percentage of full output capacity. (How accurate is it, I don't know, but it seems to be pretty close based on what I've seen on demand graphs from my electric provider and my observations during use). Guess what? 17% of capacity for a shower. (I've seen it as little as 7% with the 80°F input temp that sometimes occurs during summertime.) True, the input temp was 65°F. It'd be considerably higher at 40°F input. But this is south Texas, not Maine or North Dakota, so my numbers are typical for this area.

So let's see. My tankless has maximum potential capacity of 28,800 watts. 17% of that is 4,896 watts. Running that consumption for an hour is 4.896 KWH. Allowing 20 minutes showering time, which includes an allowance for the initial warm-up, that's 1.632 KWH used. My electric rate is approximately $0.085 per KWH per the last bill ... so that shower cost approximately 13.8 cents for water heating. I won't be washing any clothes or dishes today, so that's my total energy cost for hot water today.

I don't dispute that tankless units are considerably more expensive to purchase than conventional water heaters. Particularly the electrical or natural gas modifications necessary for a retrofit if replacing a conventional unit. A new construction better accomodates installation of tankless.

As has been mentioned, there's the angle that having an unlimited supply of hot water makes a person more likely to USE hot water .... or I should say, OVERUSE hot water. Having a tankless (should) make one more conscious of hot water use. With a conventional heater, you've already paid for 40 to 60 gallons of water heated to 120°F or higher. Turning on a faucet and using a half-gallon or two for washing hands or dishes involves only recovery heating of that much, plus recouping any stand-by losses (minimal though they are). With tankless, there is NO hot water until the faucet is opened, no inventory on-hand. So part of the trick to using tankless efficiently and wisely is to NOT use hot water unless it's REALLY needed, and then to use only as much as IS needed and AT the needed temperature.

There's also the aspect that since the water is heated on-the-fly, a higher flow-rate does require more energy. Flow-rate restrictions may be involved at the tankless, but the USER can also reduce flow-rates at the usage point. Running that kitchen faucet at 1 GPM instead of 3 GPM will take much less instantaneous energy to heat the water. So what if it takes 3 mins to fill the kitchen sink instead of 1 minute? ... I'm not in *that* big of a hurry.

Many of the arguments against tankless are going at it from the angle of using hot water with tankless exactly as with a conventional water heater ... without making any behavior / usage adjustments to faciliate tankless efficiency. Well, of course, there may be little or no benefit in that case.

Interesting side-note: The previous owner of my house advised that the tankless unit occasionally trips a breaker, if a faucet is run full-open, or if two faucets are run at full-open. He said "add a little more cold water to keep that from happening." He lived in the house for about 7 months. In the one year that I've been there, I've not had a breaker trip at all. He had the tankless temp set at the default 115°F. I've reduced it to 105°F. Even when raising it to 112°F to fill one of the whirlpool tubs (there are two in the house), no breaker trips. When raising the temp to 140°F to zap a load of whites, no breaker trips. I had guests for a weekend in December, two showers at the same time, no tripping. I have to wonder what he was doing to cause the tripping.

In regards to tankless being more trouble-prone, is that supposition or fact? It kind of reminds me of people who bash plasma TVs. "Plasmas only last 3 years." "You'll have burn-in." Well, my plasma has passed three years with no trouble or burn-in.

Tankless water heaters CLEARLY are NOT for everyone. Nothing is for everyone. Anyone who doesn't care for tankless and feels that any potential benefit for themselves is outweighed by cost, lifestyle changes, etc., I'm thrilled to death for you, that a conventional water heater will do the job. I find that tankless fits my lifestyle, without requiring any drastic changes to how I use hot water. I like the hi-tech aspect of being able to precisely set the water temperature for a task. I don't have to maintain an "inventory" of heated water. The unit was already in the house when I bought it. Would I have installed a tankless if I had the choice? I'm sure the thought would never have crossed my mind. Is there a bottom-line saving of capital cost vs. potential energy saving? In the short-term, no. In the long-term, maybe. Would I install a tankless now if I built a house? Based on my experience with it, yes, I likely would.

And beaglebuddy, I saw your post in another thread wishing for a timer that would work on your gas conventional water heater. Wouldn't a timer add unnecessary complexity, electricity, mechanics and/or electronics, when you've expressed pleasure/satisfaction that those things are not involved?

    Bookmark   January 18, 2006 at 8:51PM
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As for the timer, if I bought one it would have to be relatively inexpensive as the savings would not be great, and if it stopped working I would just disconnect it and still have H/W. Many timers are mechanical, it's P.C. boards that I have found to be unreliable not to mention expensive and completely debilitating when broke down. I suppose T/L could be fine for some people, if they happen to be a miserly troll living in a minimalist hovel who spend their spare time counting pennies and collecting aluminum cans to turn in, but for the rest of us w/ family members living busy lives ect.. we don't want to wait or share turns using the H/W. And a breakdown on a T/L will leave you dead in the water. Even on an elect. storage usually one element burns out and you still have limited H/W. What will you do if your P.C. board burns out ? who knows how to fix these things ? and how long will it take to get a part shipped ? If you are happy w/ yours, I am happy for you. My concern is people who think these are great and don't know what they are getting into. Please don't take offense to all this drivel I just like to drone on.

    Bookmark   January 18, 2006 at 10:27PM
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And sometimes you pay more for more high-techy type of stuff, just because you want to. Is a plasma better than a CRT? Nope. Just flatter, and some think "cooler" in the gee-willikers sense. Not everything is pure dollars and sense.

I met with the heating guy today. We're now talking 4 fan coils each with a tank, running from 2 water to water geothermal units, for 4 zone controllability. Could 1 monster geo unit the job? Maybe. But controllability is certainly worth it to me. Quality, in my opinion, for how I live and what drives me crazy.

Good topic though, and thanks for raising it beaglebuddy. You're right, some people wouldn't research the topic to make an informed decision and be very unhappy with the result. For others, perfect. "Vive est la difference".

    Bookmark   January 19, 2006 at 12:19AM
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Have you considered solar, either for potable or to be tied into this space heating tank, it seems to have come along way towards being more reliable, and it is a sourse of free energy. I see you live in Canada, perhaps it's not feasable. Solar water heating could certainly be used more widespread and would lessen our dependence on fossil fuels. I understand your desire for quality, I say function over form and dw says it reversed and so goes the endless argument between spouces all over the planet (and perhaps the universe)

    Bookmark   January 19, 2006 at 11:58AM
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Solar is a good idea, but not at all popular here, I'm not sure why. It might be our extreme winters, though this one has been beautifully mild. I remember reading much about energy efficiency in the late 70's when the first series of oil shocks hit. Active solar water heating was used a bit, but risk of freezing, coroding copper pipes, ugly black panels on the roof, all seemed to dissuade the mainstream from using it. I'm sure technology is leaps and bounds better now. I do know solar is used in Arizona (almost moved there a few years ago).

I'm spec-ing mostly electric appliances, as here in Manitoba we have an abundance of relatively cheap hydroelectric power, plus we're starting to install wind farms. Electricity rates are government regulated, a political hot potato, so for better or worse electricity costs me less than potential "market" rates, whereas natural gas is a true commodity, an integrated North American market, with all its ups, downs, arbitrage, and geopolitical factors. The Mrs. wants a gas cooktop and fireplace, otherwise everything else is electric. Besides, I can work on electric appliances and circuitry myself, whereas only a licenced gas fitter is legally allowed to do anything to gas appliances, including paying the provincial government a $35 gas "permit" fee for each item installed, replaced, etc.

We're making our house R2000 certified, a Canadian super energy efficiency standard, plus using geothermal heating, so we're doing our part for low consumption and future cost savings.

    Bookmark   January 19, 2006 at 11:05PM
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Interesting, it's the opposite here gas is cheap and elect. expensive in spite of recent gas price hikes. They seemed to have solved the freezing issue w/ some kind of anti-freeze thru the panels instead of water and it's much simpler w/ fewer controls and such, or at least more reliable ones. But you still have the issue of ugly panels. BTW there is a federal law that trumps any local or condo ordinance if someone wants solar. I plan to put some sort of system on the roof of our home in Hawaii when we move there later this year. Elect. rates are the highest in the nation in Hawaii and of course its mostly sunny and never freezes.

    Bookmark   January 19, 2006 at 11:33PM
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I've been living with a gas fired "joke" for 8 years with absolutely zero problems, but you probably don't want to hear that. In fact, you've closed your mind period, and then made inflammatory statements without being open to new data or new experiences. I don't know why I even posted for your trolling pleasure, but rest assured, there are folks in existance who are perfectly happy with tankless water heaters and who don't shower at a scalding 120° either. It's done everything I've ever asked of it, as long as I was reasonable in my requests. BTW, it's a Myson and needs zero electricity to run, so we can even have hot water during power outages without fear of running out.

    Bookmark   January 20, 2006 at 10:38AM
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High initial cost, lack of advertised savings, inability to use a recirc. system these are some of the problems that still exist. I was talking to a fellow plumber friend yesterday and he told me about problems he was having when used on a home w/ old galvanized pipes,seems as though a pre filter was required as there are some small passages inside the unit that can clog w/ debris. Just trying to give people the facts.

    Bookmark   January 20, 2006 at 11:22AM
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Seems to me that a proper balance of "facts" would include mention of both benefits/likes and drawbacks/dislikes. Other people have posted benefits and likes they've experienced, while you've posted only complaints and dislikes.

    Bookmark   January 20, 2006 at 4:25PM
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Rufusdoofus, I post only complaints and dislikes because that is how I feel about the product, others have posted what they feel are benefits. Hows this, a good aplication for T/L is for it to be plumbed to a jacuzzi tub seperately.

    Bookmark   January 21, 2006 at 10:56AM
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Don't know a thing about the details of a tankless but I live in Minnesota and have horses. I attached mine to a hose. Turn on the freezeless faucet and let it fill and keep filling tankless and then I use it to wash horses or hose wounds or whatever I need hot water for in an unheated barn in a Minnesota winter. When I am done, I remove hose and drain heater and turn it off. Works for me. I bought a cheap one ($278) and ran it to the 240 receptacle in my barn. Has lasted for the last three years with use in summer and winter.

    Bookmark   January 23, 2006 at 11:23PM
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This sounds like an exellent use for a tankless, rather than in your home trying to provide all your hot water. Here is a point of use application and fluctuations in temp do not really matter. Just make sure you don't run it dry.

    Bookmark   January 24, 2006 at 10:26AM
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I didn't read all of this thread, but I agree with beaglebuddies logic. I have installed a few tankless units for customers and they are very costly to install, and may never pay for themselves in some cases. They do have many parts that will at some point go bad, at which point they will probably be obsolete or hard to get. They are not new technology though so who knows really, but I like the tank units better.

    Bookmark   January 27, 2006 at 9:58PM
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You should read the whole thing, There are some good arguments.I really liked akchicago's link to an article about T/L

    Bookmark   January 28, 2006 at 1:18PM
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I'm with the beagle. Tankless is a Rube Goldberg solution to a non-existent problem. Conventional tanked gas WHs are marvels of non-electric engineering refinement... VERY nice when power was out for *14+ DAYS* following Hurricane Wilma a few months ago... hot shower by candlelight... AHHHhhh. All most of them need is a cheap insulation blanket and the occasional flushing.

(BTW, many owners of gas-T/Ls were rather chagrined to find their units were USELESS during power outages due to ELECTRIC START and no provision whatsoever for manual/match starting--WTH! No easy way to hook up to generator either.) The larger flue needed for gas T/L is also a labor bugaboo in Florida, due to concrete tile roofs, resealing, etc.

And retro-fitting ELECTRIC tankless falls somewhere between fool's errand and outright nightmare, due to the extra 120-200 AMPS of wiring & breakers needed, extra service drop+meter from POCO, etc.

Also, let's face it, the MARKETING and SALES of tankless WHs often falls between Used Cars and Time-shares on the scale of Sleaze and Misinformation. A credible product doesn't need this.

    Bookmark   February 17, 2006 at 10:43PM
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My thread has been reborne !
I am very upset to learn that the goverment is giving rebates for installing a T/L, or so they say on the radio, and most of these units are made overseas by foreign co's.
What's next ? rebates for a toyota hybrid, yeah I know.
You said it well fixizin.

    Bookmark   February 18, 2006 at 12:59AM
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No easy way to hook up to generator either.

Don't know what you are looking at, but EVERY gas water I have seen installed in the last 15 years simply plugged into a 120V outlet. Hooking up to a generator is as hard as running an extension cord.

- Tony

    Bookmark   February 18, 2006 at 10:43AM
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So you have to run the generator to get gas hot water ?

    Bookmark   February 19, 2006 at 1:39AM
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The install I'm referring to was hardwired, and I believe far less than 15 years old... homeowner was not knowledgeable about back-feeding generator to main panel.

So you have to run the generator to get gas hot water ?
Yep, the T/L shysters call that "progress" and "advanced technology"... LOL!

However, that's not NEARLY as funny as the gizmo-fools who had plenty of canned goods, but no simple manual (*ta-DAH!*) CAN OPENER! Had to fire up the genset to open cans... lol.

Lemme tell you, between the noise and the gasoline shortages, you could only run your gen 6-10 hours/day... thank goodness it was a late Oct. (BIZZARE!) hurricane, and the weather was IDYLLIC afterwards.

    Bookmark   February 19, 2006 at 2:24AM
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T/L W/H's, fancy water saving appliances and hybrid cars are a classic case of spending a buck to chase a nickel.

    Bookmark   February 19, 2006 at 3:55PM
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Spending a buck to chase a nickel, lol. However in the case of hybrid or hydrogen powered cars, gov't incentives may be a case of stocking the pond with trout until the infrastructure reaches critical mass... if you'll excuse the mixed metaphor.

Cars getting 60+ MPG is a direction we need to go in. Plus the torque/acceleration of DC motors is AWESOME! (Witness modern locomotives.)

Tankless WHs *do* have applications (military field housing/hospitals, quick to pack and go?), but the typical home is seldom, if ever, one of them. Sham sales tactics tell the story.

    Bookmark   February 19, 2006 at 10:10PM
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Chemocurl zn5b/6a Indiana

Boy you guys really tell it like it is. I recently checked on Tankless wh in Consumer Reports...and can't believe I was actually considering one.

I presently keep my electric at a comfortable heat, (not hot), and have hot water in 2 seconds in the kitchen, where I use it most. I can't imagine having to wait any longer than that. Waiting (and wasting water)wasn't even covered in the report.

Sue...who thanks you all

    Bookmark   February 23, 2006 at 2:17AM
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Sue, I'm afraid the internet has disrupted my habit of hitting the local library and perusing Consumer Reports... what did they have to say about T/L???

    Bookmark   February 25, 2006 at 1:39PM
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So you have to run the generator to get gas hot water ?

My bad ... when I read fixizin's post about being without power, for some reason I was thinking "power vent" instead of "tankless".

In that case, no you wouldn't need power once the tank was hot - like let it run for an hour and you'd be good for the day. But that is an entirely different topic...

- Tony

    Bookmark   February 25, 2006 at 3:39PM
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Chemocurl zn5b/6a Indiana

Can't really remember too much what they said, but they did not adress the having to wait for hot water...having to waste running water for 2 minutes (or any amout of time for that matter). To me that is really a waste of water (and for some higher sewage bills).

And they in no way addressed what was said above, that I have copied and pasted below...I too think simple is the best way to go...though I have electric and when I have to someday replace it, it will be with an energy efficient electric model with a long warranty. I say this because of the signicant rise in propane gas in my area, that I wouldn't consider a gas one now.

From above..."Conventional storage heaters have to be amongst the greatest inventions ever. They work without the benefit of electricity, have no moving parts, no p.c. boards to burn out, sensors to lime up, impellers to wear out ect... and no parts to be backordered on a slow boat from china, and they are extremely reliable.With tankless you will need a new oversized flue,probably a larger gas line and you won't have the flow capacity, sure you can make hot water forever but only at a reduced flow rate, so forget about 2 people taking a shower at the same time, yeah you can get a big tankless that has the flow rate but they can cost maybe $2000.00 I think and forget about a recirculating system unless you want a complicated system of pumps, sensors and maybe a small tank How much do you spend on hot water a month".

I want something that if it breaks down, it will maybe be as simple as replacing an element or thermostat...something I can do myself.

Sue...who likes to do things herself

    Bookmark   February 28, 2006 at 12:09PM
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I did a comparison on my gas usage with my tankless. Granted I had new construction, and how much savings may depend on different levels of construction, insulation, etc. However:

I paid $1200.00 (including installation) for mine (Rinnai 2520) in new construction. I didn't pay extra for 3/4" gas line. Vented through exterior wall. Normal gas water heater (50 gal) about $300.00 installed (at least that's what I was quoted by the builder).

Moved from a 1400 sq ft home (w/electric range, gas water, 80% gas furnace) to 2500 sq ft home (w/gas range, gas water, 80% gas furnace). Prices increased from Dec last year to this year--25%. Size of home increase--78%. Actual bill increase 30%. Kept the temp on the furnace at 69-72 in both houses, in the new house set water heater to 104 most of the time. Avg therms used in old house .6 therms per sq ft. Avg therms in new house? .4 therms--a DECREASE in gas usage by 28% despite the new gas range. Water bill remains the same, AND we now have a 3rd person in the home 2 weekends a month. I don't believe that the tankless doesn't contribute to a good portion of that gas savings.

If I save an average of 25% on a $150.00 gas bill each month, I will recoup my cost (an $900 deficit) in a little over 2 years. Doesn't sound bad to me!

    Bookmark   February 28, 2006 at 1:13PM
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Catluvr this is not even close to an apples to apples comparison, hot water is usually a very small portion of the gas bill, call on us in the summer when the furnace isn't being used. Your savings are probably coming from the space heating side what with your new airtight house w/ insulated windows and walls.

    Bookmark   February 28, 2006 at 9:14PM
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We'll see! Old house was new too....

    Bookmark   February 28, 2006 at 10:04PM
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Hi everybody,
This thread was of interest to me as we are thinking of installing an electric tankless H W heater in the new ensuite bathroom we are building (point of use application).

As you will note from my user name, I live in Victoria Australia and the problem is that we do not have these units for sale as yet in Australia...we do have the gas ones. We seem to be very conservative about new technology...(You'll probably tell me they've been around for years!)Lol.

Anyway, we were thinking of importing one and I think what I'm trying to ask is 'are they safe'to install in the room itself.

I have done some research on the net and there are forums which talk about the horrors of a Mexican? shower rose heater which delivers electrically heated hot water at the shower head.

I hope you don't mind me asking this beaglebuddy on your thread..it's just that I was attracted to the title.

Thanks in advance for any feed back coming my way.

    Bookmark   March 1, 2006 at 6:53PM
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Isn't gas cheap in Australia ? why electric ? How about solar in sunny australia ?

    Bookmark   March 2, 2006 at 12:57PM
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I'm sorry I should have added more detail. This new bathroom is at a weekend home in the country.

There is no piped gas to the property and we thought to bring in gas tanks would be introducing another energy source for no reason. Solar yes.. but we are only there on the weekends and the cost and work involved in fitting up solar seems excessive. This bathroom is just for our new bedroom with a view away from the house and will only be used a few times on the weekend. This room has a beamed ceiling and therefore no ceiling space to put a tank. The rest of the 3 bed house is nicely serviced by normal electric tank stored hot water.

Perhaps this is the point about these tankless units. It seems to me that one at point of use would seem to suit our requirements cheaply and easily. It's just that they are not available in this country, and I am wondering why....again is there a safety issue ? Realistically, I can't imagine that there is a problem because it's really just heating water with electricity, whether it's in a tank or a tankless unit.

    Bookmark   March 2, 2006 at 6:44PM
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Well if you do import one, you may have a hell of a time getting it fixed if and when it does break down, repairing it will probably be down to you. No saftey issues. My mother is from Warragul ever heard of it ?

    Bookmark   March 3, 2006 at 1:11AM
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WOW! What a discussion. They installed one on This Old House last week in an Atlanta home, and it seemed like a slam dunk idea. Apparently not that simple.

Reminds me of the Toyota Prius argument. Anybody see the Wall Street Journal commentaries by the economist who argued that you'd never get your money back when "investing" in a Prius? It was a couple months ago or so. Folks went into a defense fury over his economic argument.

    Bookmark   March 3, 2006 at 8:01AM
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Of course you will never get your money back on a hybrid, by the time you start to break even the batteries will need to be replaced at considerable cost, and what about the pollution from all these old lead acid batteries ? Hybrid cars are more of a political statement, it's their own I hate Bush and American foreign policy car.

    Bookmark   March 3, 2006 at 1:10PM
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Yep, that's about right.

I tried to share this info, based ONLY on the economics, and one of my friends' blood pressure went through the roof. I could do nothing to get it down (but be quiet....and I'm hardly a fan of the yokels in power.)

    Bookmark   March 3, 2006 at 2:53PM
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Neely from AUS-land: the only safety issue is theoretical, i.e. you will need about 4-6 times more electric power for a tankLESS unit over conventional, depending on the flow rate. So bigger gauge wires, bigger circuit breakers, etc., ergo, bigger fire danger if something not wired correctly.

(Do I understand that this bedroom is a separate pod/cabin away from the main house? Perhaps an insulated run of pipe will serve?)

Agree on the hybrid cars. Remember, the ONLY reason they exist is because a small cadre of (IIRC) UNelected CALIFORNIA "officials" http://www.arb.ca.gov/homepage.htm MANDATED that 10% of cars sold in their HUGE market be hybrid by year 2???. Once again the Peoples' Republik of Kalee-fornya goes off on a tangent that is not necessarily sound.

Since conservation of energy applies, the only tangible benefit OVERALL from all-electric cars is DISPLACING THE AIR POLLUTION from where the people (and lungs) are, to someplace outside the cit-ay where the power plant is. I can see where this would be attractive to valley cities such as L.A. and Las Vegas.

Certainly the 1990s phenomenon of a single commuter or small family in a monstrous 4-ton Ford Excursion was a step in the wrong direction.

    Bookmark   March 6, 2006 at 12:45AM
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Speaking to you from the land of fruits and nuts, and hybrid cars I can say you are correct.
People are reporting that hybrid owners are so obsessed w/ fuel economy that they drive too slow on the highway and accelerate too slowly thus holding up traffic and making people pissed off and hating hybrids.

    Bookmark   March 6, 2006 at 1:38AM
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Uh, sort of. But the larger picture is that cleaner-generated power (eg wind power) that feeds the grid (more and more) helps over time. That combined with better fuel economy, and things are beginning to move in the right direction. But they haven't found the holy grail. And the batteries (longevity, need for replacement, disposal, etc.) are an issue now. Better to buy a gas car with good gas mileage, or convert an old diesel to veggie. Bio-Willie, anyone?...bottom line is that the Prius drivers are paying dearly out of pocket environmental "statement", as long as they realize that.

    Bookmark   March 6, 2006 at 10:18AM
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Wind power kills too many birds, just ask the Kennedy's about wind power, they killed a project off Marthas Vineyard, oh but wait RFK jr. is a huge enviromental whacko I suppose that would make him a hipocrite.

    Bookmark   March 6, 2006 at 10:59PM
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Final word from down here in AUSland.

To beaglebuddy...you mentioned your mother came from Warragul, well I drive through there every Friday on my way to our weekender. My place is about 30 miles further east.

And to fixizin...yes maybe a run of insulated pipe from the main household tank would be easier than buying an item not available in this country.

Bye for now

    Bookmark   March 6, 2006 at 11:23PM
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I only skimmed this thread but I'd add that a
tankless shouldn't? ever flood your basement
like I've had water tanks do.
And its not all money. I will spend extra
for an environmental benefit. Of course running
water for 4 minutes to get hot water doesn't sound
good. I think bigger houses and bigger expectations generally = more than one unit?

    Bookmark   March 7, 2006 at 10:39AM
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Neely, my grandfather was the pharmacist probably from around 1920 to 1960 his name was Evans, I understand that the building may still be there.
Marys1000, they certainly have the capability to flood, they have a very thin copper heat exchanger that will one day fail, and if you are concerned w/ the enviroment consider solar hot water this is a source of free hot water.

    Bookmark   March 8, 2006 at 12:42AM
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RE Leaking and Flooding: Once again, worse with tankless/tHankless. ;')

One of the MANY time-refined features of conventional (tanked) WHs is that they almost always leak-fail slowly, very rarely catastrophically. Thus installing them in a $12 drip pan, the kind with sides only 3" high, prevents 99.9% of property damage. i.e. if you hear a dripping sound, or notice water in the pan, time to take action.

OTOH, tankless has more places to spring a leak from, no drip pan to catch it, and the water pressure will keep it spewing until you close the input valve.

There are enough disappointments in life... no need to go out a BUY another one called "tankless"... unless of course you're a masochist.

    Bookmark   March 19, 2006 at 10:55PM
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The thread that won't die ! Anyone else want to try me with tankless insanity ?!

    Bookmark   March 20, 2006 at 12:52AM
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beaglebud, the only thing I can figure is they must have young women with MAJOR CLEAVAGE out there selling tHankless... in which case I may need to "re-investigate" and do some "comparison shopping"... LOL!

True story: Major pharmaceutical companies are now hiring former (recent) college cheerleaders to make the rounds of the doctors' offices, pushing the latest drug du jour! When I asked my doc about it, he said "Hey, the airlines aren't hiring them anymore, so why not? I got cheerleaders schmoozing me 6 times a week... what's not to like?..."

No lie, they hire a lot of them from here:

    Bookmark   March 20, 2006 at 4:55AM
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Fixizin - statistically women make most of the home appliance and home fixture decisions of the household. I think tankless manufacturers would not be doing themselves any favors by using sexy young women to sell tankless; that would not help their sales numbers at all. Instead, what those manufacturers are actually doing is appealing to women's practical and pragmatic nature, by giving a spiel that tankless WHs will save energy and money, and provide their families with endless hot water, whether that's true or not.

    Bookmark   March 20, 2006 at 10:47AM
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Lots to like about cheerleaders.

    Bookmark   March 20, 2006 at 11:54AM
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Saving water is critical. My electric 60 gal water heater is about 35 ft from my shower. It takes about 3 gallons of water to get hot water to my shower which takes about 1 minute. Instead of wasting that water I catch it in a 2 1/2 gal bucket. After the bucket is full I put the bucket of water in the kitchen. Once the water cools off my cat loves to drink water out of that bucket. If the bucket is empty the cat lets me know by kicking it or he starts hollering. Before my shower the next day I pour the water outdoors onto my plant beds.
Sorry to get off topic but if I install an electric tankless water heater I couldn't carry 2 - 5 gallon buckets. :-) There is no way I would want to waste 10 gallons of water per day by using an electric tankless water heater. That's 300 gallons of fresh water wasted a month. 3650 gallons of fresh water wasted per year. Multiply that by the number of your family members then you are being very wasteful. :-)
I had the power company install a load control on my electric hot water heater in 2000. But the power company is still going to build that nuclear power plant. :-)

    Bookmark   March 23, 2006 at 8:12PM
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Shannon+2, you're probably right, but while I see the washer, dryer, dishwasher, etc. as the woman's choice, aren't the garage door opener, furnace, and yes, WATER HEATER, usually in the "urr, urr, urr" realm of manly decisions? ;')

And after all, women like cheerleaders too... well, mostly just the women who used to be cheerleaders... LOL.

    Bookmark   March 24, 2006 at 1:48AM
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we have a noritz tankless ( about $1500) and I hate it. We got it because we kept running out of hot water when we had guests..felt like we needed a showering schedule so folks could get clean! Anyway - the tank is in the basement and it takes 2-3 mins to get up to the masterbath. Sometimes we get a blast of cold water right in the midst of a hot shower. We changed from a conventional water heater...what is the answer--multiple water heaters for each bathroom? multiple small tankless for each level of house?

    Bookmark   March 25, 2006 at 9:55AM
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Well, I was down at Lowes last week and I saw a buxom young cheerleader taking a shower.

She tried to wheel it out while the cashier wasnt looking. I guess the police arrived and cornered her in the parking lot.

Im pretty sure she was a basketball cheerleader. She kept hollering: "Dont shoot. Dont Shoot."

For Aaarrrrrggghhhhh, who asks, " what is the answer--multiple water heaters for each bathroom? multiple small tankless for each level of house?", You can have a small storage-type heater with recirculating HOT water. Feed this with water from the demand type.


    Bookmark   March 25, 2006 at 11:46AM
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You are partially correct peanuckle, yes you can have the T/L and a storage tank w/ a recirc. but the T/L should not feed the storage tank because it will be a bottleneck in the system as a T/L will only allow so much water to pass thru it, let alone heat it. Normal cold water should feed the storage tank and the T/L needs to supply hot to the storage tank indirectly thru the side taps on the storage tank w/ the aid of an aquastat and a pump. I have this set up at my weekend house, w/ a 50 gallon head start and 125k btu T/L I get lots of flow rate, but there are problems w/ this set up.
1. Some T/L are not set up to heat pre-heated water and will trip an overtemp switch at around 165 degrees as the already warm water from the tank is fed thru the T/L.
2. It takes an expensive and powerful pump to feed enough water thru the T/L to get it to turn on in a closed loop situation, much different from an open tap.
3. A rube goldberg set up of pumps,sensors and timers making the already inherently unreliable T/L even more so.

    Bookmark   March 26, 2006 at 12:10AM
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Well, Brokeback Barker, first thing we need to make clear: Pinoke dont make many mistakes, anymore. I can argue my way out of pret near anything. Between what I say that isnt true and what people thought I said, I can usually wriggle out of a tight spot.

So here goes: "You can have a small storage-type heater . Feed this with water from the demand type." Which means that there will always be HOT water in the tank for the first blast, either because it is heating by design, and may be part of a recirc loop, or because demand-fired water is running into it and back out.

I admit, I have never done this. But, if I did it would work exceedingly well.


    Bookmark   March 26, 2006 at 10:00AM
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There will only be hot water in the tank if it's an electric water heater storage tank type because if you use a gas heater there is a good chance of tripping the ECO from too hot of water, a one time only switch in the gas valve that once tripped will require a new gas valve. Then there is the bottlenecking problem.
It's my whole point about these T/L, sounds good on paper but when tried in real life, not so good, especially when one tries to use them in applications not specifically what they were intended for.

    Bookmark   March 26, 2006 at 11:41PM
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now that was funny!! and I have learned so much but fellas, relax..

    Bookmark   April 3, 2006 at 9:53PM
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Tankless water heaters have their place. I have one and any time someone mentions wanting to get one I ask them why.

The reason I have my Takagi is because we live in a very small house and I needed the space. My washer and dryer were sitting on the back porch while my water heater sat in a cozy little closet by the back door. I got the Takagi to hang on the outside wall and stacked my washer and dryer in the former water heater closet. For that application, it is a godsend.

Beaglebuddy is right that it seems to take forever to get the hot water to come out--it is not a function of how far my heater is from the faucets--like I said, I live in a very small house. The water heater is no more than 12 feet from any given faucet/appliance. I was worried that I would waste a horrible amount of water waiting for it to heat up but I've been pleasantly surprised that my water bill each month (including trash pickup) is only $12. I can't complain about that. Of course, at the same time I switched to a front loader washing machine so I'm not sure how much savings I can attribute to one appliance or the other. I did not see any decrease in my gas bill.

If the person asking me about the tankless is wanting one simply for savings, I tell them to forget it and get another tank water heater. If they want the extra space, the tankless is great but it'll cost them. I paid $1200 for my Takagi and it supports two separate appliances at once (if I had the water pressure to keep it running--which I don't). Initial cost was affordable because I had it outside and didn't need any venting. After my house addition it was suddenly inside again and I had to vent it out the roof. It cost me a little over $600 for the high heat stainless steel venting and my roof has a very low pitch.

I love mine for it's space saving feature but that's all. If we had the room I would definitely have a tank water heater.


    Bookmark   April 4, 2006 at 10:19AM
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I did not see any decrease in my gas bill.


Space saving, yep, tHankless does that, but that is so seldom necessary in the TYPICAL RESIDENTIAL SETTING. As I said above, they have their SPECIALTY applications, but this wholesale "putsch" to market them to homeowners, is just an organized SCAM, which, unfortunately, is 99% legal. (SOME states MAY take action against false claims, but...)

Beagle, your thread may set a record, lol...

    Bookmark   April 8, 2006 at 3:40PM
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Tankless water heaters have been sweeping the nation with a huge growth over the last 5 years or so. These are water heaters that do not have a tank. Many of the larger tankless companies have seen their sales grow by hundreds of percent each year! These compact units mount on a wall either inside or even outside the house and supply hot water on demand literally without end! The Europeans have been heating water with tankless heaters for years. Many people believe that within the next 5 to 10 years 50% or more of all American homes will have a tankless water heater in them! Even the big tank water heater companies have tried to jump on board by partnering with larger Japanese companies to have units private labeled for them (More on this later)

Tankless water heaters are available in electric natural gas and propane fired models. The electric tankless water heaters have advantages over tank type electric models but very few provide enough capacity to serve multiple fixtures with only one unit and may require a larger electrical service to operate them. This has kept most builders from using them in new construction. Although they do tend work well in small home, condo or apartment applications where gas is not an option. For the purpose of this tutorial we are going to talk about the gas fired units. Watch for a future article containing information on electric tankless heaters.

Tankless water heaters work on demand by using sensors and computer boards to monitor the flow of water and change the rate of firing to supply just the amount of hot water required for the current demand. (They are also called on demand heaters) This means that they burn less gas to supply hot water to something like a sink than they would if you are using multiple fixtures at the same time. This modulating firing rate also make them very efficient to operate as you are only using the exact amount of fuel needed at that time.

A term that should be avoided is "instantaneous". Tankless water heaters are not instantaneous. It does take them about 2 seconds to go from their at rest "off" mode to producing hot water at the set point temperature. This is not a big issue however. The problem is if a consumer thinks by hearing the term "instantaneous" that they will get water at every outlet in the house instantly if they get a tankless heater, they will be disappointed. Most homes have many feet of piping between the water heater and the outlets and do not have a recirculating system. The amount of time it takes from when a faucet or other hot water fixture opens to when the set point water gets to that point is called "Lag Time". In todays large homes with low flow fixtures it is not uncommon to see a lag time of over 3 minutes to get hot water to remote fixtures in a home. Changing the type of water heater will not improve the speed of the delivery of water unless the location of the heater is altered or if a recirculating system is installed. Because of their small size of course, many times when a tankless heater replaces a tank, it can be moved to a more central location or nearer to the fixtures it is to serve. This may cut down on the lag time considerably

Tankless Water heaters save space in a home because they take up NO floor space. They also do not require protection from vehicles if installed in a garage and are so small they can be installed in a crawl space or attic as well. If you really need space, many can be installed outdoors giving you all of your interior space back. Just be sure to choose a model designed for outdoor installation and with freeze protection for your area. (More on this later also)

Energy Savings

Tankless water heaters save fuel because they do not have to maintain a supply of hot water in a tank and are typically "always off". Tank type heaters fire on and off all the time to maintain the temperature of water in the tank within about 10̊ - 15̊ of the thermostat setting. (This is called "Stand-by heat loss") This also can result in some noticeable temperature difference. Tankless water heaters provide hot water to the set point temperature plus or minus 2̊.

Another thing that makes a tankless hot water heater more fuel-efficient is that they are "fully modulating". In other words they only use the fuel needed to heat the water to the set point at the current flow rate. If you are washing your hands using under 1 gallon per minute (GPM) you will be at a lower firing rate than you would be if you are filling your tub at 3 GPM. This works much like your car. When you are sitting still the car is idling. When you want to go or go faster you give it more gas and when you get where you are going you turn it off. With their "always off" condition and their modulating capabilities it is common to see up to a 50% reduction in fuel use when changing from a tank type heater to a tankless unit.

If you are going to change from a 50-gallon gas heater to a tankless you are probably not going to realize quite that much energy savings. In fact a 50-gallon tank water heater does not use much more fuel at all compared to most tankless heaters. However a 50-gallon tank heater only can really give you about 40 gallons of hot water per use before you begin running out of hot water. The tankless heater will deliver more than 300 gallons per hour for most of the year and you can never run out! If it is an electric tank water heater that you are replacing, your savings may be higher than 50% depending on the size of the tank. If you really want to know what your savings may be look for the yellow "Energy Guide" sticker on your existing heater and look for the one on the tankless unit you are considering. This will give you a good idea of what to expect. Of course your personal use will effect this as well. If you have a family of 6 that has never had enough hot water with a 50 gallon tank heater, your bill might just go up because now your family will not be taking cold showers or have to shorten them. If you have a vacation home that is occupied only on weekends or using the tankless for something like a school locker room, your savings will be greater because the tankless unit is "always off" eliminating a lot more stand-by heat losses.

Part of the decision making process is; What do you want? Endless hot water may be worth the additional investment to you even without an energy payback.

Location Location Location

Builders like the tankless water heaters for several reasons, not the least of which is space savings. When you charge by the square foot for a home, saving space means that home is worth more. A tank type heater installed in garage requires a floor stand, a pipe to protect against vehicle impact and normally venting all the way to the roof. In a two-story home, this means more framing, drywall and paint to enclose it. A tankless water heater is wall mounted and can be sidewall vented, keeping the cost of venting to a minimum. It also does not take up any of the garage floor space. Being able to install tankless heaters outside or build them into a wall gives even more options that the builder never had before. This means even less venting cost (practically none) and even more space savings. Some builders will locate them centrally in a crawl space to cut down on lag time. Others will locate them near a master bath or kitchen. Some will install them in attics or outside to free up more space. Since there is no tank to burst, installing a tankless heater in an attic is not as risky as installing a tank there. Even with a drain pan, a tank water heater in an attic is a catastrophe waiting to happen! A drain pan that is 3" deep will not do much good if the bottom blows out of a 50-gallon or larger tank water heater. (This is not an uncommon occurrence!)

Outdoor Installation

Many of the better tankless companies have models that be installed outdoors. This frees up all of the interior space and does away with venting costs or combustion air issues. These units will have their own freeze prevention systems however you will need to protect your water piping from freezing. This can be done with a pipe cover kit or recessed wall box, which can be insulated. It is also recommended that you install self-regulating heating cable on the piping to keep it above freezing. Outdoor units require power at all times to operate their freeze prevention system. In the event of a power outage in freezing weather, you will need to prevent you tankless from freezing by leaving a faucet dripping or draining the unit until the power comes back on. A "back-up" power supply or generator is also an option and there have been some solenoid valve products developed that will automatically valve off and drain down a tankless water heater in the event of a power outage.


Another reason that builders like tankless water heaters is that they are able to provide hot water to todays popular large tubs. A standard bathtub holds about 35 gallons to the overflow. The popular soaking tubs hold anywhere from 45 gallons to over 80 and just filling up the tub leaves most without any hot water with a tank type heater for a period of time. A tankless can fill all the tubs of a home and then provide back to back showers, do the dishes, and wash the clothes. A tank type heater has to be very large to do all of these things without running out. We are only limited to the flow rate our tankless unit can provide. Choosing a tankless heater with the proper capacity for our house makes it possible to handle multiple hot water needs at once without the worry of running out of hot water.

Until now, most people made "water rules" to determine who showers when, or when they could do the clothes or dishes. This goes away with a tankless water heater.

Some people mistakenly think that they will only be able to run one fixture at a time with tankless heater. While this may be true of the "Home Center" models, this is far from accurate when speaking about the professional grade heaters from Noritz, Rinnai and Takagi. These models have the capacity to operate 3 showers or more at the same time! Some will correctly claim that tankless water heaters limit the flow rate to make sure you get the setpoint temperature and say that this means you will not be able to do multiple things within the home using hot water. This is simply not true. Choosing the right unit is important as discussed a little later, but making this claim is like comparing all tank water heaters to the old 30-gallon tank heaters that would run out after every use. Todays tankless water heaters provide more than enough capacity to meet any hot water need from a one-bathroom house to a hotel. You just need to choose the correct system for your application just like any other hot water system.

Here is something else to consider when choosing your tankless heater. Asking it to operate three showers, the kitchen sink, the washing machine, the dishwasher and a laundry sink at the same time is not only unrealisticyour water pipes cant carry that much water! Most homes only have a ¾" hot water main and most are now in PEX or CPVC materials. These piping system can not carry more than about 8 - 10 GPM total, including cold water. Also, many new homes typically see less than 2 GPM at a showerhead due to pressure looses in the piping. In other words if you choose a tankless heater that can deliver between 6-8GPM in the warm months and 4+ GPM in the winter months you will be quite happy in a typical 3-1/2 bath or less home. You should avoid the tendency of some to oversize a tankless system based on unrealistic system demands. If in doubt, contact the manufacture for help.

Capacities of these water heaters have improved greatly over the first tankless models that showed up about 10 years ago in the US. The largest of these tankless companies, Noritz, has eleven models currently available in the US that range from 6.3 GPM to the largest output model available in the world at 13.2GPM. Rinnai models produce the same flow rates as the residential Noritz heaters and Takagi also has units in this range. Noritz even has commercial grade models that can produce up to 13.2 gallons per minute (752 gallons per hour from one unit!) Most of these products can be installed in multi-unit installations for high flow rate demands like luxury homes, large shower system with body sprays, locker rooms or hotels. (More on this later as well.)

Many tankless water heaters are also installed with a remote control unit that makes it easy to change the set point temperature of the unit. One manufacturer, Noritz, has a standard remote that lets you set an alarm to the capacity of your tub. You then set the temperature you would like and fill with just the hot water. When the unit measures the gallons set an alarm sounds to remind you shut off the water. Another manufacturer, Rinnai, is able to provide multiple remotes to serve the same heater to provide for multiple locations to change the temperature of the hot water if you like. These digital remote control panels also provide diagnostics for the water heater in the event that there is a problem. They flash a fault code to help service personnel find and fix any problems that may come up quickly.

The better tankless heaters by Noritz, Rinnai and Takagi totally control outlet temperature so they can NOT be "overshot" giving you less than the set point temperature. You always get setpoint temperature plus or minus 1 or 2̊ (Unlike a tank which is + or - about 10̊) Electric units and home center models do not have this ability. I would advise avoiding the home center models completely as they lack the technology and BTUs to give you good performance. In units that can not control their outlet flow, you will need to "throttle" the flow rate yourself at the outlet. This also means that if you are taking a shower and someone else turns on another fixture needing hot water, you may get a big surprise as the water temperature drops considerably in your shower!


The better tankless heaters are very easy to work on. (I say the better ones because I have not had to work on a home center unit yet) Like anything else, training is preferred but any good contractor with a cell phone and a Philips screw driver should be able to take care of a problem using the tech support lines of the big 3 listed above. A manometer (Device used to measure gas pressure is also a very handy tool to have.

How long do they last? About 20 years on average. Compare that to the 12-year average of tank heaters. This also contributes to the "total value" of the product since this means lower cost of ownership when factoring in replacement cost and life span of the product. Add in the long-term energy savings and your tankless heater just might pay for itself and in some cases its replacement!

Keep in mind however that installing these units outside in cold climates if there were a power outage, there is no freeze protection to these units until power is restored. You should protect the unit as detailed above. Most homeowners policies do not cover the water heaters themselves so it is a good idea to provide a generator in these installations or just put the unit indoors.

Choosing The Right Sized Unit

The first thing we need to do is establish the peak hot water demand for the job. In a home this is usually the number of showerheads, X the flow rate X 80%. Example: 3 showers @ 2.5GPM each = 7.5GPM X 80% = 6GPM peak demand.

You want to choose a tankless unit that can meet or at least get close to this demand during the warm half of the year. (Remember it is VERY uncommon to have a demand like this actually happen in a home, plus we are not going to install a unit that can not control the flow rate anyway.) If you are within 1 GPM of this rate you will be happy. It is not possible for most people, even plumbers to tell the difference between 1 GPM and 3 GPM without a direct caparison next to it.

The proper size unit for the home above would be something like the Noritz N-063S or the N-069M. Rinnai 2532 or Takagi T-K1S would also be a good choice.

Professionals: Please talk to your local wholesaler about attending a training class on these products. They must be installed properly to work well and installing them improperly may result in damage to the tankless heater, poor performance, premature failure or injury to the homeowner.

What about the tank manufacturers?

Good question. In the United States, over 9.5 MILLION tank type water heaters are sold every year! About half of them are electric. That is a huge market. Every time a tankless company sells a tankless water heater, the tank companies loose a little bit of their market share. (They dont sell a tank) It did not take very long for this to get the attention of the big tank companies.

These companies quickly looked into the market they had some serious questions to ask and decisions to make. The questions would be along these lines: Is this a fad that will go away? Do these things really do what they say they can do? How long have these products been in us in other parts of the world and what is their track record? How long will i t take us to produce a market viable unit?

These great companies are full of very smart people. They got their answers and had a group "Uh-oh" moment. They made a conscious decision that they would not roll over and let the "invaders" take over their market without a fight.

They found out that over 25 years of research and development went into these products. With estimates of 5 years before half of the market flipped to tankless, they had to act fast. They knew they could "Reverse Engineer" the products but too takes a lot of time and they would have to be careful to keep from violating patents.

The first step by a few of them was to attempt to slow things down. They did this by putting out letters, and articles touting the "negatives" of tankless heaters. While this was going on on the surface, they were behind closed doors with the lawyers striking deals with the tankless companies to have units private labeled for them in an effort to slow down their shrinking market share until they can catch up with the technology.

The results so far are this: Bradford White has Rinnai manufacturing its "Everhot" tankless water heater line. It IS the Rinnai line with the BW name on it. State and A. O. Smith have Noritz manufacturing theirs.

Now dont think that the very savvy Japanese companys were putting the cart before the horse. They know what is going on and they know that they own the technologyfor now. They simply set the whole thing up so their original products still have better pricing on the street. They knew that the tank companies would find someone willing to get the quick sale. By doing this they at least kept them from partnering with companies making lower quality units. (That could have started a whole new problem for tankless)

One very large company even went to the trouble of taking "their" new tankless water heater and putting against their tried and true gas fired tank water heaters in a "test". The parameters of the test were set up to with high levels of water hardness. They knew that the tankless would require cleaning because of it and their tanks would not. (Because you cant!) One thing they did not bother to tell anyone or include in their "short term" test was that had this test been allowed to continue, the hardness would have certainly ruined the tanks and required them to be replaced a lot sooner than the tankless which could simply be cleaned. This was done also to try to slow down the onslaught of tankless while they tried to figure out what to do next.

Most of these tank companies are still producing papers trying to slow the growth of tankless. (Even the ones with their "private labeled" products!) They will sometimes make claims using the lower quality of the available units to try to show them as "point of use" of all them a "Niche product" even eluding to tankless as a fad at times. They will make statements claiming that they dont believe in tankless water heaters as "whole house" units. These are just attempts to "stem the tide" as long as they can unit they can catch up. Some will print more than others but it is all for the same reason. They need to get people to NOT consider tankless water heaters for as long as they can to protect their own interests.

Rumor has it (And they are just rumors) are that they are all reverse engineering at this moment and will have units ready sometime in the next 5 years. Well have to wait and see on that one. At least for now, they are trying to keep up with the private labeled Japanese units and they are participating in the market.

So, the big tank companies are worried, as they should be. They are doing what they can, and they are not going away. Tankless is to water heating what indoor toilets have been to bathrooms!


Tankless water heaters usually have a warranty that covers the heat exchanger and the parts separately. The heat exchanger is the main part, much like the tank in a tank water hater. Normally the warranty is for about 10 years on the heat exchanger and 3-5 years on the rest of the parts. This average warranty also reflects on the average life expectancy of tankless heaters. (20 years!)

A brief word about warranties. Manufacturers (Of all Products) tend to set warranties at about half of the life expectancy. Your cars, your dishwasher, your water heater, all have a warranty that is about one half of the average life expectancy of that product.

The nice thing is that with a tankless, even if the main part (the heat exchanger) fails after warranty, you have the choice. Replace the heat exchanger or replace the whole unit. You do not have this luxury if your tank fails in a tank water heater.


Venting Tankless Water Heaters

Venting is very important to gas fired tankless water heaters. If these products are not vented properly, many bad things can happen. The least of these is the unit may fail very soon in its life span due to condensate being allowed to enter the product. At the very worse, Carbon Monoxide Poisoning could occur. "Shortcuts" should never be taken in regards to the venting system on this or any other piece of equipment that burns gas, oil, wood or other products. All manufacturers instructions should be followed and you should always make sure that your heater is vented properly.

Tankless water heaters can have their venting go either out a side wall with horizontal venting or up through the roof. Keeping the venting run as short as possible is both good for the heater and will help keep costs down. In fact, many times it makes sense to move the location of the heater closer to an outside wall and run the water lines to it rather than run longer venting. (Copper, PEX and CPVC are relatively cheap compared to Stainless Steel vent piping!) This also may give you a reason to get some needed space back within the home.

Most tankless water heaters require a special stainless steel vent piping material. This material is known as "Category III" and is typically AL29-4C Stainless steel. This is required because the combustion efficiency of the heaters make it very likely that condensate will be formed within the venting system. This condensate, although there is not a lot of it, is highly acidic and will destroy standard vent material in a short time. Type "B" gas vent can not be used on most of these heaters for this reason. Another reason this vent is required is that the vent systems are under pressure from the fan within the heater. This is known as "Positive Pressure" venting and requires that the vent system be UL listed as positive pressure and sealed to prevent carbon monoxide from leaking out into the occupied space. Tankless water heaters as well as other products also have maximum lengths that you can run the venting. The number of elbows required in the system shortens these distances. Always consult your manufacturer instructions and never exceed these distances!

It is also not allowed to tie these vents together or tie them into an existing masonry chimney. The condensing gasses would quickly begin to cause damage to the masonry and result in structural damage to the property as well as a very unsafe condition with carbon monoxide. If you can run the proper vent product up through an existing chimney to the outlet and provide the proper condensate drain to protect the unit, you can use the existing chimney as a "chase" to run your new vent pipe in. (Consult individual manufacturers instructions!)

Most manufacturers require that you either slope horizontal venting away from the heater, or provide some type of condensate drain within 3 of the vent connection to protect the unit from damage caused by condensate. The condensate in the venting will destroy the heat exchanger if allowed to run back to the unit. Units not vented properly will have their heat exchangers ruined within a few short years. Most vent manufacturers now have the ability to provide a drain tee even when venting is installed straight up to properly protect the unit.

Venting is probably the most important part of a tankless heater installation. To recap this part: No "B" vent! No Common Venting! No connecting to masonry chimneys without lining it with the proper vent pipe. Use Stainless steel UL listed positive pressure venting made for these products. Allow for proper removal of condensate within the vent system. Keep venting runs to a minimum length. Never exceed manufacturers venting lengths. Read and obey your owners manual!

Gas Piping

Tankless water heaters save energy because they are always off and they modulate their firing rate to the demand. However just because they save energy does not mean your existing gas line is large enough. When these products have to go to high fire to meet a large demand you must be able to provide enough gas for the unit to function properly. Do not assume that if your existing gas line is the same size as the connection to your tankless heater that your pipe is large enough. In an existing home it probably is not!

Most homes with tank water heaters do not have a gas line sized properly for a tankless water heater, especially if other equipment is connected to the gas piping system. The best solution for this is to run a separate gas line to the tankless from the meter without re-running the entire gas main. There are many good flexible gas piping systems that can make this job simple and limit the number of joints and installation time of the new gas line.

Needless to say, gas piping is not something the average DIYer should be attempting. The money saved on running a gas line is not worth the risk of your home and family. Gas piping should always be checked or installed by a licensed and insured contractor trained for gas piping.

Water Pipe Connections

Tankless water heaters do not come with relief valves like tank water heaters. Most of the world does not require them on tankless systems. These relief valves should be installed on the hot water piping leaving the tankless heater. An easy way to do this is to use a tankless water heater valve set like the EXP made by Webstone. This valve set gives you only 5 joints to assemble. It has union connections at the heater, which will greatly speed up replacement later. It has ball isolation valves on each side, drain valves that give you the ability to flush the tankless system later or drain the unit easily without draining the whole house and it comes with the proper relief valve. All of this is in a very compact kit and makes hooking up the water side of your heater fast and easy. This one pipe kit saves about 16 joints at the heater! Make sure you get the one with the relief valve sized for your heater.

Minimum Flow Rates

A very important consideration when deciding on your tankless water heaters is minimum flow rate. All tankless heaters need a minimum flow rate and pressure to work properly. You should look for a model that has a minimum flow rate of .5 GPM for a residential application and one that will operate well down to about 30 PSI system pressure.

Even with a minimum flow rate of .5 GPM it is possible to have a flow related problem but it is a lot easier to solve. If you have single handle bathroom (lavatory) faucets you are going to need to open them all the way to get the minimum flow rate to fire the heater, especially in the summer time. This is why I advise to not use tankless water heaters with high minimum flow rates in homes. Commercial units can have minimum flow rates of .75GPM . That is about as high a minimum flow rate as you would want in a home. Most homes requiring these units (Large luxury homes with "carwash" shower systems) do not have very low flow fixtures and typically do not need to worry about minimum flow rates.

Also, Debris in faucet aerators and showerheads can cut their flow rates down to a point that will keep the tankless from firing. Make sure your fixtures are free from debris.

Most 2.5 GPM showerheads will not supply 2.5GPM of flow in a new home. This is due to system pressure looses. Every foot of pipe and each fitting in the water main has a pressure loss. At far ends of the home these add up and can cause lower flow rates at fixtures like showerheads. This is not a big problem though and rarely causes issues with the better tankless water heaters. Most people never know the difference and as stated above, it is almost impossible for most people, even plumbers to tell the difference between 1.5GPM and 2.5 GPM in todays showerheads without measuring the flow. As long as the velocity of the water is acceptable most people are quite happy and of course some showerheads are better than others.

Most tankless water heaters have an inlet water filter. This should be checked and cleaned regularly to make sure that flow is not slowed or stopped by this filter. This is the first place to look whenever there is a problem with your tankless water heater. Look for it in your owners manual.

Hard or Acidic water

Water quality issues can be a concern for tankless water heaters in some areas. To understand the concern you first need to understand how certain water conditions effect tank and tankless water heaters.

Hard water is water with large amounts of dissolved solids in it. If you have hard water and pour it into a clean glass, you can not see the hardness. The hardness is "in suspension" in the water and as the water is heated the particles cling together and drop out of suspension. In a tank water heater they sink to the bottom and form a layer of scale where they build up. In a tankless most of the particles are flushed from the system as they drop out of suspension.

Since a tank heater heats water when you are not using it to maintain the stored water, they tend to get that sediment on the bottom of the tank. This is because the particles are dropping out of suspension when there is no movement of water in the tank. Even when you are using hot water with a tank heater there is very little movement of the water. As the sediment builds on the bottom of most gas fired tank water heater it becomes an insulator and causes the steel to be over heated without a good transfer of the heat to the water on the other side of the sediment. Over time, the fire burns through the tank or the welds fail and the tank begins to leak. If the leak is not spotted, then the tank will eventually rupture flooding the house!

In a tankless water heater, the particles are being flushed from the system as they drop out of suspension due to the high flow rate through the coils. Some hardness may adhere to the walls of the tubing but it will be a lot slower process than with a tank. If the water is so hard that the tankless coil becomes fouled the heater will send an "Overheat" or "Lime" error code (Usually represented with a number) and lock out alerting the homeowner that something is wrong. A technician can then come out, diagnose the problem (With help from the heater error codes) and de-scale the unit, renewing it in about 45 minutes.

Scaling of gas tankless water heaters is a fairly rare thing. When it happens the water is typically so hard that the homeowner should consider a water softener system. Water that is that hard is effecting every other appliance in the home. Toilet fill valves, faucets, washing machines, dishwashers, ice makers, etc. In fact if the water quality is that poor, a softener system will pay for itself by making these other things last longer and require less maintenance and less frequent replacement, including the tankless water heater!

Acidic water is another problem. Most water is not going to have this kind of issue, especially if you are on a public supply. However, if you know you have acidic water, you need to consider installing a neutralizing system to protect your tankless water heater. Any acidic water that will eat copper piping will eat the copper piping in a tankless water heater as well and shorten its life as well as possibly voiding the warrantee.

If you do not know if you have hard water or acidic water, chances are you dont and should worry about it. If you want to be sure, there are many testing services available for free from companies that sell the treatment systems or you can contact your local water company or extension agency for testing.

Even if a tankless heater does develop a leak in the heat exchanger, that part can be replaced and your tankless is back in service without a replacement. With a tank heater, once the tank gets a leak, you throw it away and get another one. This also makes tankless heaters more environmentally friendly because less material is going into landfills. Think about the millions of tank water heaters going into landfills every year! What if water heaters lasted twice as long and were repairable? How much landfill space could we save?

"Cold water Sandwiches" (Not just for breakfast anymore)

The "Cold water sandwich" is a phenomenon that can effect a tankless water heater home that is less likely to effect a home with a tank heater. It happens in homes with tank heaters but can be less noticeable. This is where a section of piping has hot water that has cooled off between uses and between the piping in the walls or water heater. Piping in the walls looses its heat slower than piping in a crawl space or basement. If there is a hot water draw and then the flow is stopped for while, the water in the most exposed piping cools off faster than the water in the piping in the walls. If someone opens a fixture at the right time, the first water out of the tap is hot, then goes cooler as the water from below gets to the outlet, then heats up again as water from the heater gets to the fixture. In some homes a tankless water heater can exaggerate this a bit.

Imagine the large house with a tankless heater and a short draw. One person turns on a faucet at one end of the home and gets hot water to wash their hands. A few minutes later another person goes into another area and washes their hands. The water in the pipes is still hot. They are almost done when the temperature goes cold for a few seconds then back to hot again. Viola one cold water sandwich at its best.

It does not happen every time and it does not seem to be a regular issue except in the case of homes with recirculating hot water systems where this has not been accounted for. We will get into that later.

Here is why it happens: When the flow stops a tankless heater stops firing and the draft fan continues to run as a "post purge" to ensure that all exhaust is moved out of the venting system. It runs for about one minute and during this time it cools off the heat exchanger. The heat exchanger holds about .2 gallons of water. (a little less that a quart) When the heater senses flow again it fires back to provide hot water for the next draw. The water in the piping may still be hot, but the very first bit of water to leave the heat exchanger is not heated. It does take about 1 - 2 seconds for the tankless heater to get going. Now this first quart of water enters the pipe with the water that is still hot from the last draw and begins to mix with it as it travels down the line. Eventually the lower temperature water gets to the user and they notice the temperature fluctuation.

Is this normal? Yes. Is it acceptable? Maybe. In most homes this is perfectly acceptable since it is not a common occurrence and the short draws are usually hand washing and when this does happen it is only a minor issue. However if you have just paid for a recirculating system for your home and every time the pump comes on you get a little slug of cooler water in the piping, it might not be acceptable. When you jump into the shower at the far end of the home expecting instant hot water and get the surprise from the cold water sandwich, you probably will want to know how to deal with it. If you are an installer of tankless heaters, then you will want to read and understand the next part well to provide a perfect hot water system every time.

Recirculating systems (To loop or not to loop that is the question)

Recirculating systems can work great with tankless water heaters when properly designed and installed. The proper system will provide instant hot water at most if not all outlets in the home and save the customer water by not having to run the hot water until hot water gets to the outlet.

The traditional way is to install a recirculation system is to install pump and a return loop back to the inlet side of the heater with a couple of flow check valves. This will work of course but you have to install pump with enough "head" capacity to get through the high head loss of the tankless. Higher head pumps also use more electricity to operate than their lower head counterparts. How big a deal is that? Well if a higher head pump uses $.02 more to operate per kWh then the other pump, over a 20-year operating period that calculates into the thousands of dollars over the life of the pump!

Another consideration is most tankless water heaters get their energy efficiency and their longevity by being "always off". Installing a recirculating system this way puts a lot more wear on the unit and may cut its warranty in many cases. Add the cold water sandwich to the equation and there is a better way.

One of the first things that installers dealt with was the cold water sandwich. This was managed by installing a very small storage tank (About 5 gallons) right after the tankless heater. This way, if a small slug of hot water got out of the tankless it would mix with the 5 gallons of hot water in the tank and be diluted to a point where no temperature change would be noticed. That fixes the cold water sandwich but still leaves the high head pump and the warranty issue to deal with.

At some point someone came up with the idea of turning that small storage tank into a 5 or 6 gallon 110V tank water heater. They are very small, insulated, and can plug into an outlet. Then they hooked up the recirc loop between the tankless heater and the small tank heater effectively by-passing the tankless, saving the warranty and keeping the energy efficiency of the unit. The small tank heater does not have to heat the water very much. When the system is first turned on, a hot water fixture is opened filling the entire system with hot water including the small tank. The tank and recirculating system now only has to use enough energy to maintain the loop temperature. This is usually only about a 5̊ rise. With insulation on the hot water piping, it is a very efficient solution! Instant hot water, as efficient as you can be with very low energy demands, and all the hot water you will ever need.

A great diagram of this system is available on the Noritz website here:

Twin tankless systems

There are many reasons to go to a "Twin" tankless system. You may have a big house with 4 or more baths and a large family, or you may have a large flow capacity shower system installed and need a higher flow rate. A good gas tankless water heater can easily operate 3 showers in the winter months, and even 4 in the summer months due to warmer incoming water temperatures. If you need more that that you may want to consider a twin system.

When you install a twin system you should always choose a tankless water heater that is made to operate this way. If you were to just choose two tankless heaters and pipe them together you would compound their minimum flow rates. If you have two tankless heaters with a .5GPM minimum flow rate and piped them in parallel without installing them properly, you will end up with a 1GPM minimum flow rate before either heater will fire! Plus you would have a very unbalanced flow through each heater. If you hooked them up in series, you would never be able to get a higher flow rate than the full capacity of one heater.

Noritz, Rinnai and Takagi all have units that are made for multi-unit and twin system installation.

With a Noritz system you would pipe the heaters in parallel and use their "Quick connect cable" to connect the two computers. Simply plug in the two ends of the cable to the connector inside the heater and connect the ground wires. This is the most simple twin system available at this time. Hooked up this way, when there is a low demand one unit will work by itself with the other automatically valves and turned off. When the demand increases to about 50% of the capacity of the first unit, the second unit is brought online and load is balanced between them. The heaters will work together up to their peak capacity. They also will act as a "lead/Lag" system in that the "lead" unit will change after every 8 operating hours or every 24 "stand-by" hours so it does not get more wear than the other one. Another great benefit of this system is that if one unit develops a problem, the system will lock it out and valve it off, sending an error code to the remote. The other heater will operate normally up to its capacity. This is called "Redundancy" and it means you are never out of hot water, even if there is a problem.

With a Rinnai or Takagi twin system everything works the same way but with a slightly different wiring needed. To connect the computers for these models you will need to have their multi-unit control installed and the wiring harness connected per the instructions. This is not a very difficult thing to do and the instructions do a very good job in guiding the plumber to hooking up the system for the first time. These systems also give the redundancy benefit and lead/lag control.

There are very few homes that need more hot water than a twin tankless system can produce. With the average heater from Noritz, Rinnai or Takagi, you will get from .5GPM 16GPM depending on incoming water temperature. Thats from the lowest flow rate required for hand washing up to 960 gallons per hour of hot water! All that and you still have not taken up any floor space of the home, and have no tanks to burst.

The question comes up often "Should I just put one at each end of the house and let them be separate?" You can of course do this if you like. It is two separate hot water systems and you do not get the redundancy of the true twin system however you may eliminate the need for a recirculating system in a larger home. The choice is up to you and you should simply consider what benefits are most important to you and how your home will be used. If it is just a lot of bathrooms like a 5 or 6 bath home, but you do not have any high flow fixtures, it may make more sense to just place them at opposite ends and have two hot water tankless systems. This is very likely to cost less money up front then a twin system with a recirculating system in a large home.

Multi-unit tankless systems

The multi-unit tankless systems work much like the twin systems above. The systems from Noritz, Rinnai and Takagi all use a multi-unit control that acts as a lead/lag system. You get a lot of redundancy with a system like this and they can handle any hot water job up to about 317 gallons per minute 19,000 gallons per hour! (24 Noritz N-132M heaters)

These are usually commercial applications with very high demands like locker rooms, dormitories, hotels or industrial applications. Every once in a while a large luxury home is built that has a high flow demand that requires such a system.

With the Noritz system you have one multi-unit control that handles up to 6 of their commercial heater. (Up to 13.2GPM each!) If you need more than that, you can use more than one multi-unit control or they have multi-unit controls that go up to 12 heaters or 24 heaters with one control.

With the Rinnai and Takagi, they have a "Master" Multi-unit control that is installed in one of the heaters and a "slave" multi-unit control to install in each consecutive heater.

The wiring harness are included in with all these systems and are not difficult for the professional installer although proper training is highly recommended. All three of these companies have very good technical support teams to help any contractor who needs or would like a little reassurance on their first big job.

Look at this example: A high school has a locker room with 24 showers. They have a 10 year old 400 gallon tank water heaters that is "always on" 24/7/365 and it has begun to leak needing replacement probably due to sediment build up caused by constantly heating and reheating water that is not moving. A typical locker room has to have a hot water system sized that will meet the peak demand, however the kids almost NEVER use it! At best, the showers get used a few dozen times a year after a football or other game. The rest of the year, the big old tank is just sitting there wasting valuable energy.

For this job* I would recommend 4 Noritz N-132M units with SC201-6M control. (*This is for my area and meant only as an example! Your area may require more or less capacity.)

This system would be "always off" but with plenty of capacity to supply the team with hot water when they needed it. With todays high gas prices the savings would be well into the thousands of dollars per year and the heaters would probably last past their 20-year life expectance due to light use. An installation like this usually pays for itself in the first 2-5 years after installation in energy savings and is a much better use of taxpayer money.

    Bookmark   August 26, 2006 at 4:45AM
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Many, many thanks to hankb. I'd begun to suspect that most complaints about tankless rose from improper gas supply (and now I know, improper venting). Your post is so comprehensive--very helpful. We are off to contract with a Rinnai installer this week on new construction. Your post will help us be informed consumers. Thanks!

    Bookmark   August 26, 2006 at 2:16PM
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Wow. Good reading.

    Bookmark   August 26, 2006 at 3:16PM
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Outstanding post! Answers just about everything, and should put all of the naysayers in their place. Too many builders/trades are afraid to embrace new technology. And too many homeowners blame the equipment when the problems lie with the installation and the wrong application of a particular product.

Agian, this has to be one the best, well written posts of any that I have read on any home posting board. Good Job!

    Bookmark   August 26, 2006 at 8:23PM
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Hate to tell you this, but I didnt read it.
1. The post is obsolete.
2. The response it too long.
3. This is a forum not a library.

Anybody can use it however they like. But, it is worth noting, that the use of this forum for problem-solving has become almost nil.

What happened? I see that ever since the site was sold, and a s-house-ful of advertising was foisted on non-members, the posting are down. Not to complain, really, but this was a fine resource for DIY-people a few months ago.

Today, most of the postings are about hardware items and not plumbing itself. Theres room for that. But to the extent it duplicates another forum, there is no reason to do that.

This particular question is burned-out.

There is a place for Demand HOT water systems. They are not the answer for all users. But to call them a joke is neither appropriate nor sound.

Funny how the stupidest memos run into nigh 100 answers, while serious questions go begging.

Now if you have a problem with my posting, I regret that. There is certainly a place for your reply. Unfortunately, it is where the sun never shines.


    Bookmark   August 26, 2006 at 9:17PM
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Unless for have FACTS to refute hankb's claims and facts; I suggest that you not wasting your time on tankless WH's and start looking for the little green men that the government is hiding in area 51.

    Bookmark   September 2, 2006 at 9:14AM
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I was thinking of adding a tankless water heater but I decided to go electric instead. The tankless was going to be extremenly expensive to install.

What does everyone think of going with several point-of-use electric tankless water heaters particularly for new construction? I can see several advantages. Perhaps five or six for a house? A couple showers, a couple sinks, a washer and a dishwasher for example. The net price should be little more than the price of the tanks since the plumber would not have much more to do than he would with plumbing a "normal" house. The electrician would have a little extra work but again not much additional work.

    Bookmark   September 2, 2006 at 11:05PM
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It is telling that despite the long length of the message that Hankb posted, which is ostensibly an exhaustive review of the subject, it did not mention the crux of the decision of whether to have a gas tankless water heater or not. That is, what climate you live in. If you live in northern climate where for 4-6 months of the year the incoming water is around 40-50 degrees, the amount of energy (gas) needed to raise that incoming water to an instant hot is enormous. Today, traditional hot water heaters are so well insulated, their use of gas to keep the water hot on an ongoing basis is significantly less than what a tankless needs to provide instant hot in colder weather. In a cold climate, combine the cost of greater gas usage, with the upfront cost of the unit itself, the installation costs of venting and gas piping (addressed in the article), and tankless is many times more expensive than a traditional water heater.

On the other hand, if one lives in e.g. Alabama, as does Trailrunner who has posted above, then the gas tankless could be a good alternative to a traditional water heater. Trailrunner, I noted you posted on another thread that your savings this month (a summer month) was $9.00 for gas usage and $3.00 for water usage. Clearly a decrease in the cost of utilities was not your primary objective, and I understand that you really appreciate the instant nature of the tankless water heater. I know that my issue with these units is the way they are marketed and portrayed as the Greatest Thing Ever for everybody, without consideration of the upfront cost, or in a cold climate, the energy usage and cost. I think people are suckered into spending these large amounts upfront and ongoing and would be better off with a traditional water heater in a cold climate.

    Bookmark   September 3, 2006 at 5:32PM
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chicago : you are SO correct. Place geogrphically is a huge consideration. We will see as I said to you in the other post what happens this winter. Our ground water doesn't get as cold as yours !! We still do have winter. I did not have any way to put it in the house so we were "vain" and got the tankless. I would never suggest it to anyone else , they must research it for their own situation as you say. Caroline

    Bookmark   September 3, 2006 at 8:49PM
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I checked the stats when taking a shower yesterday evening. Input water temp 83°F. For an output temp of 101°F @ 1.1 GPM, my electric tankless ran at 10% to 11% of full capacity. That's between 2,880 and 3,168 watts. For about 13 mins of run-time. Estimated cost of that shower based on the rate from my last electric bill is 8 cents. That's wayyy less than the cost of my air conditioner, which pulls about 5,500 watts and runs much longer than 13 mins per day.

If I need only about 14 gallons of water at 101°F for the shower, what sense is there in heating 50 gallons to 120°F? I doubt that can be done for 8 cents.

    Bookmark   September 4, 2006 at 12:34AM
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dadoes , I am so glad you know how to do all that. I don't know how to get those stats off of our gas Noritz. If you happen to know and can tell me I will try to document for others . Thanks. Caroline

    Bookmark   September 4, 2006 at 4:44AM
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Yep, they're not a "joke", they just don't make economic or environmental sense for MOST residential applications.

But hey, if you don't believe the math, then keep making those plumbers, electricians, and tankless sales people happy, and yourself not so happy.

HEY, I want to get in on the action too--I'm the kind of guy who can put your tankless WH ON THE INTERNET! Yep, you can talk to your WH from work or from your Palm Pilot! Download those important stats wirelessly while on a biz trip, LOL!!!

Besides, there's enough "conveniences" in our modern world that need to be "fiddled with"... why add the WH to the list? Oh, I'm getting in the shower, set the temp to 105F, oh, I'm doing a load of laundry, jack it up to 140F, oh now so-and-so wants a bath, she likes it at 109.3F, oops, time to run the dishwasher, set it to 132F... WAIT, lemme guess: they have one with a REMOTE CONTROL now, so you don't have to keep running outside or to the utility area/garage... :rolleyes:

    Bookmark   September 4, 2006 at 6:19AM
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Dadoes, I hope you'll report again on your expenses in January, when the incoming water will not be 83°F. I don't know what state you live in, but even if it's a state like Florida, the incoming water in January will not be 83°F, and so will put a greater demand on your tankless unit to heat it I am interested to know what your increased utility usage will be--whether it will be minor, or of a greater magnitude. I also wish someone would post similar statistics with a gas tankless, which I believe is a more voracious use of energy than electric tankless.

    Bookmark   September 4, 2006 at 9:25AM
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Pure curiosity, but why do some contributors become so rilled up by another poster making a different choice/decision ? I haven't read a lot of entirely ignorant, uninformed questions or responses, so, assuming an informed poster/consumer, why be so very upset that this individual may make a different choice than one might make for one's self?

Adding helpful information that is current and realistic is terrific, but I am really curious why some are so quick to add almost angry diatribes to the mix.

Tankless is a technology that works in many, many other countries (including Japan, which I might note is not in a tropical or sub tropical and has lots of extremely cold weather in the north). It works in Europe. US residents do use hot water differently from residents of many other countries; tankless companies have responded with units quite different in capacity and convenience from someone's legacy/ten-year old tankless.

Does this make tankless correct for every application? No. But some of what is above seems terribly heated taking into consideration how the choice of any one of us does not affect directly any other of us. Hope some PhD candidate in psych is out there trolling for thesis material. Why are strangers so ready to go nuts over other people's decisions?

    Bookmark   September 4, 2006 at 11:37AM
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akchicago, although I did my best to make a comparable analysis from one home to another (which was quickly shot down by detractors, lol), I did see a marked decrease in overall gas usage per sq ft for usage from Oct-Feb. Recently I did a one month comparison using the same approach for the month of June (when incoming water temp is warmer) and came up with the same number (25% less gas usage per sq ft). I still intend to do a 5 month comparison for anyone who seems to think that gas tankless are insatiable gas guzzlers. BTW I live in a climate very similar to Japan's (PNW). No deep freezes but there can be week long stretches below freezing in winter.

PS I did get your email--I will answer. :)

    Bookmark   September 4, 2006 at 4:11PM
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fixizin, I have no need of your services. I don't have a Palm Pilot, I don't go on business trips, and I have many more things to do at work than check tankless stats. Nobody is at my house (except in VERY rare circumstances) when I'm not there, so there is no hot water use to be monitored. My tankless does not have a remote control. The only time I raise the temp is for washing clothes, and it's not a problem being as the unit is hanging on the wall 2 feet from my washing machine. I don't have to remember to drop it back down, it does that automatically after 15 mins.

akchicago, I've lived in this house since late January 2005 so I'm aware of the difference between summer and winter water temps. All-electric, winter-time is when my bill is lowest. I live near the central Texas coast, where air conditioning is king. Dec 2005 had a couple cold spells.
Feb 2005, 1004 KWH, $105.
Mar 2005, 696 KWH, $87.
Apr 2005, 727 KWH, $90.
May 2005, 655 KWH, $83.
Jun 2005, 1296 KWH, $142.
Jul 2006, 1471 KWH, $158.
Aug 2005, 1521 KWH, $155.
Sep 2005, 1615 KWH, $168.
Oct 2005, 1394 KWH, $144.
Nov 2005, 833 KWH, $81.
Dec 2005, 1263 KWH, $105.
Jan 2006, 1103 KWH, $97.
Feb 2006, 1083 KWH, $112.
Mar 2006, 760 KWH, $96.
Apr 2006, 831 KWH, $104.
May 2006, 1075 KWH, $127.
I won't cite the rest of this summer being as there was a problem with my air conditioning that kicked the usage higher for a couple months.

So apparently the lesson is that tankless water heaters don't work ... except for people who live in south Texas.

    Bookmark   September 4, 2006 at 4:13PM
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Dadoes, I hope my question didn't sound like I was confrontational to you. I honestly didn't mean to. I was just trying to back up my point of my Sept. 3 post on this thread--that the climate you live in is the crux of the tankless vs. traditional heater decision. My issue is that the marketing and promotion for tankless make it sound like it's the newest technology that will improve everyone's homes. It always omits the question of the large amount of energy that would be needed to heat incoming water to instant hot in a cold climate (just as Hankb's long post did). As I said in my earlier message, tankless is a good alternative, providing the luxury of instant endless hot water (and taking up almost no space), when you live in a warmer climate. Where I live, winter temps start in Nov. and you can have frost in May; incoming water temps will be around 40 degrees for several months at a time. I just think that gas tankless would be a poor choice here, and other areas with similar temps. I get frustrated that no distinction is made by the marketers and advertisers of this technology.

I am also curious as to the difference between gas tankless energy use and electric energy use, but have not seen any hard numbers or statistics, so your experience will be very helpful.

    Bookmark   September 4, 2006 at 5:33PM
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I've been considering switching to tankless as a space saving method (my current water heater takes up half a closet in my small condo - I could really use that space back).

My main concern is venting (which I hadn't considered before reading this thread). Would I be correct in assuming that it could use the same venting that my current tank uses (I have no idea what that is) or are there different requirements?

Also, how large are they? The usage would be for one shower, one sink, one dishwasher if that makes a difference. I could easily avoid running the dishwasher at the same time as the shower.

The shower is about 10' from the water heater and the kitchen sink would be furthest at maybe 20'.

What brands are recommended for this sort of usage?

I'm not especially interested in the energy issues, at the moment I'm scrambling for every square foot of storage I can find :)!



    Bookmark   September 6, 2006 at 1:19PM
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Finally, something makes sense:
A: "My main concern is venting (which I hadn't considered before reading this thread)."

Q: "Why are strangers so ready to go nuts over other people's decisions?"


OK, Jaybird, heres some information. You probably have a 3-inch gas vent, possibly 4". The demand heater will probably need a 5-inch unless it is electric. In which case you can use the old vent to store your socks.


    Bookmark   September 6, 2006 at 1:32PM
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jay, I will try to give a useful answer. We mounted ours outside so the venting issue was taken care of. The sizes of the units and flow rates are on each manufac. web site. Noritz is the one we bought and it has a very comprehensive site. The electric might be better for you and mount it on the wall in that closet. Much easier for you. Do a Google for electric demand waterheaters. Good Luck...Caroline

    Bookmark   September 6, 2006 at 1:52PM
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Thank you Caroline! If the electric version obviates the need for considering venting that seems like the way to go then. Outside mounting (or changing anything in the walls of the building) unfortunately isn't an option for me.

And thank you pinocchio - I can probably check the vent size or get the super to help me with it.

I'll go google for electric demand waterheaters now...


    Bookmark   September 6, 2006 at 2:36PM
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I just installed a Takagi T-K1S tankless water heater to replace an 8-year old, 50 gal tank. Performance has exceeded my expectations! According to the remote controller that I purchased with it, the incoming water temperature is 68 deg. and the 190,000 btu unit has no problem heating the water to 122 deg within about 10 secs . With the remote, I can adjust the temp from 95 deg to 176 deg with the press of a button. I am able to fill a bathtub in one bathroom while the other shower still has perfectly hot water. Count me as another satisfied tankless convert!

    Bookmark   September 7, 2006 at 9:47PM
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Im glad it works for you, mduett, But you said: "With the remote, I can adjust the temp from 95 deg to 176 deg with the press of a button." Huhnh? That is nice and warm: 176°. In fact, that is enough to cook pork to a well-done internal temperature.

This is called, scalding. So if the water goes to an anti-scald shower/tub faucet, it will be reduced, and allow more COLD. But I was under the impression that water heaters were required to be limited to something like 140°F.

Whatever. Ive only installed one of these units and the customer is extremely happy. Furthermore, it is not a Noritz, Rinnai or one of the classic pricey units. It is a Bosch, sold thru Lowes; and it installed very easily.

One interesting fact, is that a demand-type heater has very little water in it, so that it weighs little, even when full. It can hang on the wall of conventional frame construction. The unit does, almost, double the price of a water heater. But it is very efficient.

FWIW, some heaters qualify for a $300 IRS tax credit. Bosch is not one of them.


    Bookmark   September 8, 2006 at 7:35AM
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I think that washing a load of laundry in very hot water would be the only time that I will use this feature. I do have the code-required anti-scald device on my tub/shower.

    Bookmark   September 8, 2006 at 1:04PM
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My electric tankless can't be set higher than 140°F, and that requires a one-time adjustment of a programming option, otherwise the max is 125°F. I use 140°F occasionally for washing whites. My washer takes only about 5 gallons of hot water for a fill. I have the washer's hot tap adjusted for 1.5 GPM flow rate.

    Bookmark   September 8, 2006 at 4:30PM
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millej, DO have your venting checked out (this implies your current unit is GAS-fired), but do NOT assume your closet has the WIRING to support an ELECTRIC demand/tankLESS WH. Indeed, absent any facts, I will give you 20:1 odds that the necessary 220V wiring is NOT there, and that it will cost you a bundle to "make it so".

I note with wry amusement that the "helpful" hankb posted his long PRO-tankless screed the same day he registered here; same with mduett and his short PRO-tankless message. Not surprisingly, neither of their homepages has ANY details, not even the geographic REGION, which all agree is a HUGELY SIGNIFICANT factor in tankless usage.

This same-day-registered pro-tankless spamming is fulfilled in the following tankless thread by vnzppr.

There's probably more threads, but you get the picture... ;')

I think we can safely assume these poster(s) are paid SHILLS from the tankless industry. A LEGITIMATE APPLICATION of a technology does not require this web of deceit and evasion to prosper.

    Bookmark   September 11, 2006 at 3:12AM
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fixizin, my tankless experience actually goes back to 1992, when I was stationed in Okinawa, Japan and lived in an apartment that had a Rinnai unit providing endless hot water. I was so impressed by the performance of the unit back then, that I vowed to someday purchase one of my own.

My new Takagi unit is installed in the basement of my house in Bellingham, WA. I chose to install it on the opposite side of the house from where the old 50-gal tank is located. This worked out best, since all of my hot water points of use are located on this side of the house. It is floor-mounted/wall-secured and vented horizontally, directly through an old 2' X 2' window.

    Bookmark   September 11, 2006 at 7:07PM
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LOL, who would've thought there'd be conspiracy theories for plumbing appliances! Yes, I guess the fix IZ in, hehe.

    Bookmark   September 12, 2006 at 1:14AM
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Yep, you KNOW the fix izz in, and it bothers me on 2 fronts:

1) the smoke and mirrors LYING to consumers, most of whom don't have the technical moxie to do a valid comparison on their own. They are filled with false anxiety that while they're off at work and school, their conventional WH is at home, leading a secret life, burning all sorts of energy keeping the water hot... insulation makes this simply NOT true.

2) YOUR tax dollars subsidizing a dubious technology which has NOT shown an energy savings which warrants said subsidies.

Sure Europe has high density living and historic building preservation issues which might justify tankless, but Euros in general don't take as many showers, or wash as much laundry, plus most of America was designed for TANKed WHs, and that's what works best.

PS: Someone email beaglebuddy, and tell him his thread STILL will not die, LOL!

    Bookmark   September 18, 2006 at 1:03PM
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I am so truly curious about all the "expertise" on this board. Has anyone of the rather riled up posters done the research to know what the USGeo Survey winter water temp is in the various areas they so warn us about? Turns out that water underground is not all that cold, folks. So, if you are interested in tankless--a time tested, widely used, efficient and economical alternative which may or may not be appropriate for your home or life style or which may require more mental horsepower for the installer than is available in your area--then do your own research, call various mfg reps and you will learn a tremendous amount that some of the bloviating on this thread obscures.

My real question, though, is why are some of the posters so threatened and personally engaged in a hostile campaign when I cannot believe any one is forcing them to use a technology they so loathe. It seems, well, disproportionate to the "threat", whatever threat that is.

Happy heating to all--however you may chose to accomplisht that feat.

    Bookmark   September 20, 2006 at 11:10AM
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It seems much of the problem in this discussion is that very few of the posters have a good estimate on how much gas a tankless water heater uses when just sitting there.

My home situation is such that I have it as isolated as anyone can, short of not having anyone living in the house.
I have come to the conclusion that tank water heaters use very very little gas just to keep the water heated.

I use only 5 to 8 therms per month (natural gas).
I have a 16 year old 40 gallon water heater that sits in the basement of a San Francisco Bay Area home where the climate is moderate......winter and summer.
I use very little hot water compared to most people.
Only I live in the house.
Here is my weekly usage.......
1 shower daily (about 10 minutes)
approx. 2 dishwasher loads per week

Thats about it....(I do 95% cold water clothes washing and during the winter months I use about 20 minutes of clothes dryer use per week......just to size/fluff up a few damp items after mostly air drying them)

Importantly, I keep my water temperature low. The temperature is such that I take 100% hot water in my showers. Only on some occasions is it too hot.....and even then only a bit hot. Seldom, almost never too cool.

OK......so you can see, I have about minimal usage, and I suspect that about half the therms used go for my actual personal usage and about half to keep the water heated in the tank 24/7... I never turn the heater off or down.

So with the average therms per month being maximum of 7 therms per month (probably about 6.5 therms average)
If 50% of those are for usage and 50% are for keeping that tank heated and therms cost me about $1.00..........
then it would seem that it only costs about $3.50 per month to keep the water heated 24 hours per day....at my lower temperature setting.

Remember, this is a 16 or 17 year old water heater. Just a regular model.......no super insulated model or anything.
It does have a water heater blanket around it.

I'm guessing that 3.5 therms per month to keep the water heated is far less than any posters suspect ( assuming the other 3.5 therms are for my actual usage requireing more heating vs just letting the tank sit unused)

My usage is abnormal to be sure, but it gives some idea about what the tanks use to keep water warm.
Makes me think the claims of the tankless water heater avdocates are way over the top....exaggerations of how much less gas is used......or conserved.

I'm told that modern water heaters are even more energy saving than my old one.
Seems like real concerns about the environment should be spent in some other energy savings ideas.
When you consider the costs for the tankless water heaters, it sure seems like it will take decades to get any savings, and that only if you don't count the interest you could have made by putting the extra hundreds of dollars in the bank.
I'm thinking it only cost me about $40 per year to keep the water just sitting there heated and about $40 for the incremental hot water I use.

    Bookmark   October 17, 2006 at 12:24AM
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I'll leave all the specs to you stats stars. I'll just point out that I have a wonderful spare space in my garage to put something else I need to store or use and I have no worries of leakage. I LOVE MINE!

    Bookmark   October 24, 2006 at 1:31AM
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Let me preface this by saying I am a right of attillia the hun conservative that hates the tree hugging, prius driving, green on the outside red on the inside wackos as much as the next guy. So my concerns are not energy efficiency or saving the planet or whatever, heck I look for the most inefficient item in most consumer goods.... That said I think I may have a valid point for installation of a tankless unit(s) at my "weekend" house on the river that I may spend 20 days a year at. The two factors I am looking at are; 1. it is a manufactured home for the PC police (trailer to me...) so it basically is a 14ft by 80 ft box of matches as far as I am concerned so I am not real fond of having any gas appliances in it at all and 2. I am worried about a breach in the tank of a traditional heater since the floor is a single 3/4" layer of sawdust held together with glue that would fall apart and destroy the entire house if a tank breach occurred and water stayed on the floor in my long absences. I am about to replace the old poly-buytle plumbing and the complex set up of T's and eL's in the water heater closet with modern PEX and a manifold set up that I can cut the water to a specific point or the whole house from inside the house as well as sustain any accidental freeze up (PEX wall is flexible enough to sustain a freeze). I also am going to replace the 1982 vintage 45 gal Nat Gas tank. Tankless would be nice since closet space is at a premium and any recovered space is needed. I have one bath with a tub/shower combo, sink, and clothes washer and the kitchen sink and dishwasher. I think the negatives others are seeing would be aliviated by the minimal number of taps and, correct me if I am wrong, the fact that the heater and manifold would be on the same wall as the tub/shower tap and pipe runs would be approx 12 in. to tub, 4 ft to sink, 7 ft to washer and 15 ft. to kitchen should = fast temprature recovery on start up. My questions are what would be the correct size unit to buy, and should I use one unit for the whole house or one unit for the bath (tub/shower, sink, clothes washer) and one undersink unit for the kitchen sink/dishwasher?
Thanks for your input...

    Bookmark   October 26, 2006 at 12:52PM
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How about some real world gas experience?

We have now lived with a gas Takagi T-K2 for 13 months. Two adults, with the master suite about 80 feet as the crow flies from the unit -- pipe length easily adds 20 ft. We have the optional wired remote temp unit. We just upped the output temp from 117F to 122F (for dealing with cooler groundwater now.

We get hot water in our master shower in under 20 seconds. The sink faucets take about a minute at 1/2 open -- which they would with a tank too!

Our gas consumption, in MCF, was: June 1.4/July 1.1/August 1.2/Sept 0.9/Oct 1.2. This *includes* gas used for gas dryer and gas range and no furnace heat so far. The monthly cost for that here ranged from $20.62 - 23.49, most of which are transport and service fees -- not gas charge.

It includes 4 loads of wash per week (warm water wash only), 2 showers and 1 bath per day, 2 dishwashers per week and daily kitchen, bathroom tap use. We have no issues with guest showering at the other end of the house, upstairs, when we do.

We love the damn thing and do not miss throwing away money to heat 50 gallons of water 24x7x365.

And to correct one mistatement waaaaaaaaay upthread. Unlike a gas tank heater, you will have *no* hot water when the electricity goes out. Electricity controls the internal sensors and thermostat and valves. My wife discovered that last week about 8:15am, after I had left for work, and a storm blew through and darkened the neighborhood for 2 hours... ;-)

    Bookmark   October 26, 2006 at 5:21PM
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And, me being the "next guy" here, I also want to add that I don't hate "tree hugging, prius driving, green on the outside red on the inside wackos" and therefore wish you good luck with your quest for knowledge.... ;-)

    Bookmark   October 26, 2006 at 5:27PM
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Just for the heck of it, I see that there are people who "hate": "tree hugging, Prius driving, green on the outside red on the inside whackos."

FWIW, I consider that to be too far to the left. However, I have recently been reminded not discuss politics on this forum. So, I wont.

Nonetheless, plumbing-wise, I find it interesting that the value of conservation-ism depends so much on whose money is being discussed. Hate to have to mention this; but, on the list of people who have no HOT water, first should be the poor.

I wouldnt be allowed to say this if it were a political thing.

Fortunately, it is not. It is a mathematical thing. Have a happy computation.


    Bookmark   October 27, 2006 at 11:16PM
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That was less of a political statement and more of a , don't give a rat's butt about conservation, have these two specific reasons why tankless may be good for my specific set of circumstances, so shut up with the arguments about how tankless only saves $1.00 a year over tank units blah, blah, and answer if anyone confers that may specific set of conditions sounds like a good fit for tankless and profer up facts on how to figure the calculations on sizing the unit (I'm an attorney not a physicist....) My opening statement may have been a bit tounge in cheek (it's a literary devise called sarcasim) so lighten up. After all I wouldn't be offended if you made a comment regarding my being part of a vast right wing conspiracy out to destroy the planet or my "irrational fear of government and all the good it does", heck I'd have a laugh with you on it... Just a little context... GT

    Bookmark   October 28, 2006 at 2:46PM
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Ah, the great melting pot! I love an attorney who knows what species he is most associated with, IllinoisRiverRat; even though, I tend not to care a great lot for attorneys, as a rule.

Since no one in their right mind would re-read this thread, from the simple one-liner it began with, to this point, Ill just say, that there are different strokes for different folks. So that means, tankless and storage systems each have a place in a diverse economy, and a diverse population with a wide variety of locations and climates.

My guess and it aint a bad one, right or wrong is that, as a lawyer, you might be phishing for a great lawsuit. Rather than to just enjoy the warm-diaper feeling that comes with a great new innovation, you could be searching for a product liability. But, I only say that because you have confessed your guilt here; and the 5th Amendment requires I play it both ways.

Actually, IRR, I think you make a good point. It depends on the user. And dont be mistaken: I actually do give a Rats A, as you can see! On conservation? I look at it this way. This is the greatest land in the world and has all the natural resources we need to live peacefully together for centuries, while we educate our kids on how to power a spaceship from a urine specimen.

Meanwhile, anybody that tries to take this away from us: we should decapitate them and consider an apology, in case they still are alive.

Makes our mainstream look pretty leftish, dont you think? OK. Enough of that. Winters coming. Its time to get the HOT TUB on the deck and heat that puppy up to 106°. We can heat it with the drippings from chicken fat. Free-range chicken is OK, but the force-fed ones are better. (Taste just like chicken!)


    Bookmark   October 29, 2006 at 11:57AM
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I don't know much about the flow rate and all that technical stuff.

All I know is that the regular hot water heater didn't hold enough to fill the jacuzzi tub with hot water. It was quick to recover so we would fill the tub in 2 sessions, waiting 15 minutes between each session.

With the tankless hot water I can fill the tub in one sitting, adding cold water in to cool it off.

We are 2 old folk, so running 2 things at once isn't real necessary. In fact, don't know if I can or not, though husband said not when he installed the tankless.

My only negative is that the model we got has no temperature setting, (I know, it has something to do with water flow speed) so the hot water gets REALLY hot if run straight hot. We have no kids at home so for the 2 of us, it isn't a problem.

    Bookmark   October 29, 2006 at 2:01PM
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What do you call 1,000 lawyers at the bottom of the ocean? A good start. See I can laugh at my profession to. By the way all I do is real estate title work, not litigation let the trial lawyers have all that stress they want, I really don't want to drop over dead at 45 of a heart attack.... So I guess I would have to hire one of my friends to file the above speculated product liabilty suit just like anyone else!! Not a bad idea though, thanks for the suggestion! LOL GT

    Bookmark   October 29, 2006 at 2:51PM
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I once was into politics. (Today, politics is into me. So, were even.)

At that time I went to a political convention. (I wonder, is it OK to say that? Yeah, I think it is.) It was the one (1984) when Ronald Reagan was nominated for a second term. And so, you might expect lawyers to be as welcome as bedbugs at the hotel.

But, out in the hall there were a group of fertile women, all lawyers wives, I guess, who were wearing sweatshirts that paraphrased the classic quotation from "King Lear:" "OK. First thing we do: KISS all the lawyers." I loved it just poetry at its finest.

BTW, when I grew up, "real estate" was a household word. Yknow? You just used it. No one ever asked what it meant. So what does it mean? Is there estate that isnt real? Maybe I dont know what real means. But FWIW, it does suggest that someone has been lying about whats what for a few centuries anyway.

Its like, if you have a business, a horse-shoe-ing shop, for example. Who knows what that is worth? Better you should own a tire store. That way, when you have a flat, it doesnt smell like oats. (It will, however, smell like a Harbor Freight Outlet. You cant win.)

Anyhow, I dont like words or phrases that have state in them. "Real estate" is fraught with danger. So is, inter-state, intestate, lying in state, "the people of the state ," "Please, state your name," "This a "State"ment; NOT a BILL. (Wait til you see the bill!)"

Its a rhetorical question, IRR. I know you know that. I just dont want some moron hijacking this thread and taking off on a tangent. Incidentally, have you ever gone-off on a tangent? Powerful stuff, man. I had an uncle who ate 2 for breakfast everyday and he died of ass-fixation or so it said on the death certificate.

Hate to say, but it was a sorry state of affairs. Another nice thing about demand-type water heaters: they dont take up a lot of space or, as some would say, real estate.

Doesnt anything make sense anymore?

Well, yes. But sometimes it takes a Philadelphia Plumber to explain it.


    Bookmark   October 29, 2006 at 8:18PM
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By the way all I want out of life is an answer to the two simplistic questions of my first post, which no one seems to addres. How to mathimatically figure what size tankless unit I need and if anyone else though it was a good fit for my set of circumstances. Once that is answered, if I am struck dead I will have died a happy man. Also philadelphia plumber, isn't state a manufacturer of tank type water heaters; do I smell a conspiracy here?

Just as the descripitve of a group of cows is called a herd and a group of geese is called a gaggle do you know what a group of lawyers is called?

That's right it's a conspiracy of lawyers, look it up....

    Bookmark   October 29, 2006 at 8:33PM
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Quit trying to get back On-Topic. Youll confuse the people who start at the top. If you really need to know the answer, its best to post the specific question in a new thread. Then, the most relevant answers will appear. In fact, you can actually get the answer from a master plumber, who will calculate your pipe sizes and everything. Great place, this Plumbing Forum.

However, for the purposes of answering your simplistic question: "How to mathematically figure what size tankless unit I need and if anyone else thought it was a good fit for my set of circumstances," I should point out that that is really only one question followed by its own answer.

You see, one doesnt calculate to get there. You go to where they sell them and you buy one on Faith. Im serious. A demand-type water heater doesnt come in sizes like one of them State® water heaters. It is sold in limits. So, for about $500 depending where you shop you can get one in gas or electric that will sure as heck work for approximately one major fixture at a time.

So taking a shower or washing dishes or washing clothes are all things that one smaller unit can do continuously. If you have a greater need, such as two showers running at the same time, while someone is washing a car and shaving, you might want to consider the pricier ones, more than a $1000 for the unit.

When you add features, such as heavy gauge metals, stainless steel and nice plastic nameplates, the price can be several thousands of dollars. But you end up basically with what everyone likes to have from a water heater: HOT water.

Now, depending on an individuals personal finances, no matter which unit one buys, it will always be over-priced; and it will take a long time to get to the payback point. Of course, if you use more HOT water because it feels so good, you get there faster. For that reason the Federal Government is offering IRS credit to people who buy certain demand water heaters.

You didnt think they would let just anybody get a rebate, did you? No, for the most part, the $500-units dont qualify. The whole idea is to get millions of people to have these luxury units in their homes and then they can tax the living s--- out them. So dont spend your tax credit, yet. Im thinking of getting on Social Security and Im going to need the money.

Say, did you hear about the lawyer that ran for judge, got elected and rose up to the high court and then was convicted of a crime and sent to prison for life?

I didnt think so. Me neither.


    Bookmark   October 30, 2006 at 8:19AM
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"Say, did you hear about the lawyer that ran for judge, got elected and rose up to the high court and then was convicted of a crime and sent to prison for life?"

Hadn't heard of that one either, but have heard of a court system that figured out how to become a profit center by bringing inditements on "financial crimes", i.e. the things that used to be a matter for the civil courts, and will freely Nolle Prosequi those same said charges after restitution (basically what would have been the judgement amount in the civil courts) AND several thousand dollars in "prosecutorial charges" are paid. Sounds kinda like extortion to me, but hey they are the good guys, right?

    Bookmark   October 30, 2006 at 7:15PM
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This is the most bizarre thread I have ever read. I think Mr. Pinnochio has got a sliver (or some shape of wood) caught up his, er... somewhere.

    Bookmark   November 3, 2006 at 7:19PM
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Sorry for the mean statement.

I guess it would be a good thing if this site would let us edit or delete our posts.

It's still a bizarre thread.

    Bookmark   November 3, 2006 at 7:24PM
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Youre still new here, web-lyncher. So stay tuned for some really great writing. I have to say, there has already been some great stuff but unfortunately, most of it has been deleted by the webmaster.

Thanks for the compliment. Sometimes I wonder if anybody notices. After all, who is going to read a thread that goes on and on about tankless water heaters? Oh sure, there are such people, but they are boring, and their eyes are too close together.

Not that they arent welcome here anymore that anyone, including me. But there just isnt that much to say under one topic. But for the real studious types, who want to glean everything they can from a thread about water heaters, I cant help thinking even they have a funny bone in them somewhere.

After you get past a hundred messages, its time to think about things bizarre. For instance, I have always wondered how women hook them things with both hands behind their backs.

Uplifting; dont you agree?


    Bookmark   November 5, 2006 at 12:00PM
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Interesting thread, however, the entire problem was identified, but not addressed, at the begining. Some people simply don't want to ever have to think about the heating, cooling, sewer systems in their homes. That's fine, although it may lead to health and ecological problems, if you believe such things exist. I remember using an outhouse, a septic system, then city sewers. Not having to deal with that crap (pun intended) was a godsend. But sometimes, you just have to deal with it even if it's not simple.

The desire to Keep It Simple (for the) Stupid slows the adoption of most new technologies. It's similar to those who said the automobile would't catch on because you couldn't stop it by saying "whoa." Cars couldn't swim rivers. You had to stay near gas stations. Cars were a joke because they failed KISS.

You only need to read the posts that contain words like "BTU," "ground water temperature," or "gpm" and you can see that tankless water heaters can't meet the KISS standard. With tank heaters, the question is 40, 80, or 120 gallons. Period.

My neighbor put in hot water tank and a circulating pump in his new construction. I'd never seen anything like it. It has an expensive little pump that constantly circulates water from the tank, cooling it off in copper pipes, and causing the tank to have to cycle on even more. All this so that he gets hot water in one second at the third floor bath. Whoopee. It probably more than doubles his standby costs of storing hot water.

I used 3/8" PEX (1/2 the volume of 1/2 copper and 1/3 the heat loss) for my plumbing. Takes me 7 seconds to get full hot water at the fixture that's furthest from the heater. Only 1/2 a whoopee? Maybe. My whoopee comes at the end of the month. We both travel a lot and are only home about 1/2 of the time. My electric bill is always 1/5th of his. I'm sure a large part of that is my tankless system. I can only think, based on his wasteful hot water circulating system, that the rest of his energy use is similarly silly.

What is needed in a discussion of tankless heaters is a list of the items to consider for those willing to examine the complexities that confound the stupid (the "non-KISS" crowd). One of the posts above claimed that tankless heater manufacturers were "LYING to consumers, most of whom don't have the technical moxie to do a valid comparison on their own." I think that the facts and numbers are out there, and it isn't rocket science. Technical moxie is what the non-KISS crowd thrives on.

It appears that the one unknown item may be the heat transfer efficiency, i.e, how long does it take for the unit to reach it's rated output and how much fuel is sacrificed in order to produce instant hot water. Since most of the dissatisfied users have the gas or propane units, I'm guessing that's where the problem lies.

The electric units that I'm familiar with have the elements immersed directly in the water, as does an electric tank heater. At low flow, the first element comes on. The other two come on as flow increases, decreases, or the incoming water temp changes. Essentially all of the electric power is converted almost instantaneously to heating the water. There is no "excess heat" going up a flue. The energy loss resulting from storing hot water is saved, thereby making the electric tankless much more efficient than a tank.

Each electric element in mine has its own 40A fuse, so it's not something that can be easily retrofitted to replace an old tank. In fact, replacing an old tank with a tankless heater doesn't always work. The tankless heater has to fit the plumbing system. In some cases, the home owner may have to change habits or life style to fit the heater. This can drive the KISS crowd crazy.

I don't know the relative efficiency of the gas heat exchangers. Does the tankless gas sacrifice some efficiency in order to heat instantly? Seems to me that there would be some inefficiency from trying to instantly go from hot gas to hot water. The gas hot water storage tank may be able to save some energy because it doesn't have to heat instantly. Don't know. Something for the non-KISS people to investigate. Use some of that technical moxie.

For those who claim that the demand units can't produce enough hot water for them, the answer is simple enough for even the KISS crowd. "USE LESS WATER." A good friend of mine's wife was demanding that he remove their tankless unit because it made the temps fluctuate in the shower. I talked him into putting an in-line shut-off valve right before the unit. Turn the shower on, turn the valve down until the either the heating starts to cycle or the shower flows less water, turn the valve up a little more, and no more problems. Technically, the shower probably flows a half gallon less per minute, but the wife couldn't notice. No joke.


    Bookmark   November 28, 2006 at 4:42PM
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you are in for a big surpirse some day fellas......

once the TANKLESS starts to lime up and break down and need maintaince you are going to be crying like a baby.....

all those big saveings you think in your mind you are saveing with a tankless will go to the service man at $150
per trip twice a year when the flow rate declines and
you have to de-lime your tankless heater twice a year...

FELLAS---you are going to have to pamper your tankless heater like a little baby.
Eventually your wife will threaten you with divorce if she has to put up with it another day... then you will have to switch back to the good old tank type to keep your domestic life from going
down the toilet.....

just wait and see....

go to my web site and click on tankless for more info


    Bookmark   December 3, 2006 at 10:32AM
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Master_Plumber_Mark, unfortunately I don't have a wife to alert me when performance deteriorates. In your experience, how long might it take for that to happen if my water is ~11 grains hardness? I didn't choose a tankless water heater, it was already in the house I bought. I've found that I like it, but whether I'll get another tankless when it dies or switch to conventional tank, I can't say until all the variables are in.

    Bookmark   December 4, 2006 at 12:56AM
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"Lime up"? What's that? Again, do the research before deciding. I've never heard of lime up, so I haven't had that problem with my tankless or my tank. My guess is that, if your potable water is sludge or contains high soluable concentrations, you will likely have problems, and not just with your hot water tank (or tankless).

From what I have seen, the tank system suffers from funky sediment because it heat cycles large quantities of water in a tank. Things settle out in there and cover the bottom heating element. I've drained sludge out of a tank before when replacing an element. Never seen anything similar in a tankless system.

My demand heater holds a little less than one liter (approximately four aluminum cans of Budweiser in American Standard Measures), so there's no accumulation of sediment, lime, or Legionaire's Disease. Do a Google search on "Legionaire's Disease" and "hot water tanks" for a fun read.


    Bookmark   December 4, 2006 at 2:53AM
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Hi all,
17 yeas ago I had the misfortune to install a Thermar brand tankless gas water heater in my home. Now THAT was a POS! At least twice a year the rubber diaphram needed replacement. Only 1 parts house in the USA had Thermar parts and the price grew more exorbitant each year.
Not to mention having to crawl into the attic to take the darn thing apart and put back together with no drips.
Suffered through several years of parts availability, higher gas bills, bad thermocouples, not enough flow, thermostat shutting down burner at random times, and so on.

Never again!
I'm quite happy with my gas tank type heater, thank you.

    Bookmark   December 4, 2006 at 2:13PM
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Manufacturing methods for both tank and tankless heaters have come a long way in the last 17 years. I imagine that a performance review of your computer of 17 years ago would also be considered a POS by todays standards. Time and technology marches on.

    Bookmark   December 4, 2006 at 3:41PM
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We have a tankless (Takagi, I think) with a hot water recirculating system. We put it in to replace two gas hot water tanks. Luckily, I was home the day one of the hot water tanks decided to give up the ghost, so we were spared the expense of major water damage (and given that I'm in the midst of repairs to another house which suffered $40,000 worth of damages from a leaking toilet, I know how bad water damage can get). We couldn't be happier with our system...instant hot water at the tap, and endless to boot. We can run all kinds of things without a drop in flow. We have peace of mind knowing there won't be any more possible hot water tank disasters. And we gained a closet!

I don't know what our possible gas savings are yet (don't have previous years' info to compare as we haven't lived here that long) but I do know the tanks were making our bills pretty high... When we turned the temp on the tanks down during the summer, our gas bill dropped dramatically.

In short, we like ours! :)

    Bookmark   December 22, 2006 at 12:06PM
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hey, whos keepin an eye out for binladen? lol. anyway........... I think a tankless HW is a good application for an occasional use powder room or a guest bath.

    Bookmark   January 27, 2007 at 2:19PM
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put in a rinnai tankless love it. also i am trying to save our earth for future generations one step at a time

    Bookmark   January 28, 2007 at 7:33AM
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Tankless units are common in my area for customers calling me with no one to service them. Their heat exchanger compartments are super thin compared to the thickness of a tank heater.

When they break, you spend dearly. I'm glad there are ginny pigs to start this product's beginning.

What owners/sellers don't realize that these are gas units that require electric to operate. No saving the earth when you have coal burning powerplants turning the generators to run your gas tankless unit.

And the electric ones? The meter spins a mile a minute.

Parts are extremely expensive for these units along with availability of trained hands to service them.


    Bookmark   January 28, 2007 at 2:00PM
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Maudeb7 - I understand there are several reasons to favor a tankless, but I do not understand your comment about "trying to save the earth for future generations". I posted on another thread on this forum about hearing the president of Rinnai America on a radio interview (BTW, he was quite impressive in his knowledge and expertise). The surprising thing was that he said you should not buy a tankless heater if your goal is to save money or to save gas. Particularly in a cold climate, the gas usage for a tankless can be really high. Again, this is the guy from Rinnai talking. He said you should buy a tankless because you want endless hot water. Also, it has the advantage of a much smaller footprint than a traditional tank. But a tankless will not help in "saving the earth". Also, I hate to think of all the tank heaters going into landfills, as their owners discard them in favor of a new tankless.

    Bookmark   January 28, 2007 at 4:05PM
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Saw a friend's Bosch Aquastar opened up yesterday. It's an older model, no electricity or electronics involved. They've had it at least 5 years. He was dealing with a clogged (actually disintegrated) filter in the input water line. The heat exchanger (looked to be at least 10" in height) is similar to a radiator -- water line zig-zags through it from bottom up. He turned on a faucet while the cover was off, I saw the burner ignite. With the one faucet running, the flame was somewhat low. Less than I expected based on what I've heard about gas consumption. He turned on another faucet, flame height doubled. I don't know how intense it can get, what's the maximum output. Seeing the operation, it's understandable that there's a delay until hot water arrives at the usage point. The heat exchanger has to get hot, and the standing water in the line purged. Requires 1/2 GPM flow-rate to activate. Successive usage would be less delay after the exchanger gets heated ... of course unless/until it cools substantially. Doesn't appear to be a way to set a specific operating temperature on this older unit. The vent stack also isn't as "hefty" as I expected based on what I'd heard .. but maybe this is a moderate capacity unit. Again, based on what I observed yesterday, what I've heard my friends say in the past, and my personal experience with electric, electric tankless seems more able to modulate for maintaining the target temperature and dealing with flow-rate variations. I imagine newer gas units with electronic control systems are also better.

    Bookmark   January 28, 2007 at 6:37PM
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WOW, as somewhat of a newbie and as a simple homeowner who is simply trying to survive her remodeling project w/o making too many more mistakes, you guys seem like a lot of people with your own agendas. We have a master bath with two showers, a tub and 2 sinks and a laundry room nearby. We also have a basement with 3 other bedrooms and baths and laundry room that are used only when our 5 children and 11 grandchildren come and a kitchen, of course. I was really considering putting in a tankless near the master bath and laundry and then just using a tank system for the kitchen and guest rooms. This project has had lots of surprises and my husband and I are retired and tired and don't need water problems. After reading all of this I can't figure out if there are those that are simply hell bend against change b/c they don't, perhaps, have the expertise to do the installs or have some other personal agenda or whether the tankless WHs are truly the devil in metal and we will be forever doomed if we own one. I don't much care about saving 15cents a month or whatever. I should be lucky enough to live long enough to receive that payback. I do care, however, that we have plenty of hot water when everyone visits so I am not scheduling everyone for showers the next morning at dinner the night before. Can someone please just give me an honest answer about whether tankless would likely work for us. We are in Michigan but I don't really get the cold weather argument b/c as far as I understand, everything is about the same temp everywhere once you are 4 feet or so underground--isn't that the whole principle behind heat pumps? Oh well, what do I know, I am just a blond, a women and a patent attorney.....guess you know why I need some help.

    Bookmark   February 1, 2007 at 5:41PM
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No personal agendas and NO I didn't read this entire thread. Don't need to.

Just do this and let us know how it works out. Buy the most expensive tankless that has at least 12 gpm rating so that your not "minimizing" counting the numbers of showers and people to gather an equation on what you need.

A 12 gpm unit should cover all basis. THEN, pay whoever you want, preferably not a plumber since you don't think were able to handle the new technology and be able to install it.

Get a handyman and let him "learn as he goes" and hopefully you'll get the hot water demand you are looking for.

Water heaters are around $1000 installed, tankless you can figure double or triple that figure. But you want hot water and don't want to save 15 cents.

Go for it and make a example for the rest of your neighborhood that you can take endless hot showers. Just don't tell them how much you paid to do it.

    Bookmark   February 1, 2007 at 8:53PM
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LOL! No personal agenda? Maybe not, but sure is a buncha vitriol up there.

    Bookmark   February 1, 2007 at 10:38PM
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I have installed a few takagi tankless water heaters (upon request) and dozens of rinnias. I don't know about any other brands of tankless products, but have heard bad stories about other brands. I am also certified to install only the rinnia.
I don't know If it is ok to talk pricing on the site, but i charge $1600, $1800, and $2000 for three different rennia units in new construction. The $1800 unit I install 80% of the time. I started installing them about three years ago and am installing more every year. My customers love them and I have had Zero compplaints on them so far. The reps have told me they are a 25-year product (the same as high efiency biolers). Most water heaters I change out have lasted 10-15 years. The rinna's burn at 84% where a regular water heater burns 74-76%. The tankless also is never working when you're not using hot water. Last year my customers also cashed in on a $300 tax rebate for their tankless. We have figured they pay for themselves in 4 years. If any of my customers have a problem that I cannot fix, they will have a new unit hanging on their wall within the hour. I have access to the supplies and support in my area. I have one tankless water heater and two biolers I install because I can service, trust, and own those products.
Dual flushing tiolets, Ground source heat pumps, Solar pannels, Tankless water heaters are all wonderful products that have been proven in other countries. It takes good installers with service contracts, informed home owners and Government leadership on a national and local level to make it work. Green builing has got to be our future. We will look back in 30 years and be able to see the impact they have made. Our building and enviroment are a symbiotic relationship and our pocketbook cannot forever come first.

    Bookmark   February 2, 2007 at 3:08PM
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If you are all so angry that you can't even stomach and tolerate questions from homeowners who truly do not understand the technology and are simply trying to make good, long term choices, then why hang out on these forums? Can't you imagine that after 11 months of living in the middle of a major remodel I don't need anybody attacking me. Thanks for the sarcasm.

    Bookmark   February 3, 2007 at 3:51PM
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Plumerrick....thank you for the kind response. Do I understand you to say that you would suggest Rinnai over Takagi? We could install this unit right over the shower and vent directly to the outside. We could also easily install the gas. For 2 shower heads (and a rain shower), two sinks, a tub and a laundry room, what size Rinnai would we need (Of course it wouldn't all be used at once, I would guess that the showers could be going at once or one sink and one shower and maybe a load of laundry but not the tub). Thanks.

    Bookmark   February 3, 2007 at 4:07PM
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I don't much care about saving 15cents a month or whatever. I should be lucky enough to live long enough to receive that payback. I do care, however, that we have plenty of hot water when everyone visits so I am not scheduling everyone for showers the next morning at dinner the night before. Can someone please just give me an honest answer about whether tankless would likely work for us.

Uh, Wldsyd, I'll repeat what I wrote 4 messages above yours. That is that the President of Rinnai America himself said you should not buy a tankless heater if your goal is to save money or to save gas. Particularly in a cold climate, the gas usage for a tankless can be really high. He said you should buy a tankless because you want endless hot water. Also, it has the advantage of a much smaller footprint than a traditional tank.

That should answer your question.

If you are all so angry that you can't even stomach and tolerate questions from homeowners who truly do not understand the technology and are simply trying to make good, long term choices, then why hang out on these forums? Can't you imagine that after 11 months of living in the middle of a major remodel I don't need anybody attacking me. Thanks for the sarcasm.

In defense of Peteyboy's response to you, what I saw in your message was a challenge that said that despite all the previous 140+ posters, you still weren't provided enough information, despite posters' links, despite professional plumbers and installers opinions, despite lengthy explanations of why people felt pro or con, despite explanations of the necessary venting and gas line changes involved in tankless, despite opinions from the tankless owners who'd been living with them. You dismissed it all by saying people had "personal agendas", that the several professional responses were "those that are simply hell bend against change b/c they don't, perhaps, have the expertise to do the installs". With 140+ responses, none of which you found helpful, I cannot blame Peteyboy for his message.

BTW, you can also do a search on this Forum for "tankless", and you will come up with many more threads if you seeking more information than what was provided in this one.

    Bookmark   February 3, 2007 at 8:45PM
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Wlydsd said, "what do I know, I am just a blond, a women and a patent attorney.....guess you know why I need some help."

As a blond woman who does not find the concepts of tankless beyond my intellectual grasp, I am offended by your statement. You mean you went to law school, passed the bar, but still use the "blond woman" card? Shame on you for promulgating the stereotype. It's 2007.

    Bookmark   February 3, 2007 at 8:58PM
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Plumerrick....thank you for the kind response. Do I understand you to say that you would suggest Rinnai over Takagi? We could install this unit right over the shower and vent directly to the outside. We could also easily install the gas. For 2 shower heads (and a rain shower), two sinks, a tub and a laundry room, what size Rinnai would we need (Of course it wouldn't all be used at once, I would guess that the showers could be going at once or one sink and one shower and maybe a load of laundry but not the tub). Thanks.

    Bookmark   February 4, 2007 at 1:12PM
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For all you "Tank Heads" - Is it any different for your tanked water heaters to heat the incoming "supply water" than it is for a tankless model? They are both doing the same job, right? What difference does it make "where you live" and whether you live in a "cold climate" or not? If the incoming "cold" supply of water is 40 degrees it's 40 degree water whether a "tanked" model is heating that water or a tankless model is doing the job. In both case the supply water needs to be heated up to the desired "hot water" temperature irregardless of whether a "tanked" model is doing the heating or a tankless model is doing the heating! Why would that make the tankless model any more expensive to run that a "tanked model"? They are both essentially heating that exact same temperature supply water up to (get this) the EXACT SAME DESIRED TEMPERATURE OF WATER hence, it would cost the exact same amount due to both of the models doing the EXACT SAME JOB! The only exception is that the "tanked" model runs ALL DAY LONG - 24 hours a day - while the tankless model only runs when the hot water is called for! Needless to say, that means (without ALL OF THE STUPID MATH) that it is cheaper to run (not install but run) a tankless model than it is to run a "tanked" model to do the same job of heating water! Now the real comparison is between the amount of WATER THAT A TANKLESS MODEL "WASTES" versus the amount of GAS (OR ELECTRICITY) THAT A "TANKED" MODEL WASTES! Okay, now that we've all finally figured out what we really should be comparing (the running of the two different models), lets debate!

    Bookmark   August 18, 2007 at 5:24PM
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