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hot water on demand systems? good or not?

Posted by farmhousegirl (My Page) on
Wed, Apr 23, 14 at 22:55

Anyone know much about these? Just curiuos if they really do a good job and are worth it?


Follow-Up Postings:

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RE: hot water on demand systems? good or not?

do you mean in the kitchen, like an insta-hot? or a tankless hot water heater for the whole house?

I actually have both planned for my house. I cannot *wait* to get that insta-hot in the kitchen. I make coffee in a french press each morning. I HATE waiting for the water to boil :)


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RE: hot water on demand systems? good or not?

I'm guessing you mean a hot water recirculation system that will deliver instant hot water to any source, like a shower. Whether or not it's worth it is a personal choice, but I think installed correctly they will deliver instant hot water. For me, it was about cost - not just upfront costs but I was worried about maintaining "yet another" system in my house. There are also increased electricity costs for it to run all the time, though not having one likely increases the water consumption so it evens out.

Someone can correct me, but I think you also have to program it to ready the hot water at specific times, which wouldn't work well for our family because our showering/laundering schedule varies too much day to day.

Having said all that, the people I know who have one love it and can't believe they ever went without one. :)


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RE: hot water on demand systems? good or not?

We're using a Navien model 240A tankless water heater for our whole house. Really hoping that we end up loving it. I've read some negative reviews, but they seem to be for an older model. Mostly positive reviews for the newest model.


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RE: hot water on demand systems? good or not?

Hi, we have a water recirculator in our current home and we love it! Our water heater is in the basement so the water has a long way to travel to our bathroom and kitchen sink. With this attachment, we do have a hot water instantly! It's great! We plan to add two in the home we build.


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RE: hot water on demand systems? good or not?

I use electric tankless heaters for low-volume fixtures. They are small and inexpensive, deliver hot water instantaneously and add redundancy.
For high volume fixtures, like the main shower, I have a tankless gas heater in close proximity. Endless, quick hot water.
Also makes plumbing simpler because there's only a cold water distribution network in the house, not a parallel hot water line.
Advantage over recirc systems: System is off and consumes no power when not in use.


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RE: hot water on demand systems? good or not?

We put in 2 rinnai tankless hot water heaters...one for the Mbath (west side of house) and one for everything else (east side of house). We are very happy. Endless hot water, they maintain water temp very well so long as you run the water. If you trickle it, it gets confused and stops making hot water. They are very energy efficient. If you think about it, you probably run hot water in the Mbath maybe 20 min out of 24 hours so for most of the day, there is no energy use for that purpose. Recirc systems do require energy use all day to keep the water hot while it's perpetually circulating...not a very green solution.


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RE: hot water on demand systems? good or not?

We will have demand recirculating pumps in our new house (not sure if it is Metlund or just Metlund-like). They do not run continuously. You have to press a button in the room where you want the hot water, so there's a short wait, but I think it is worth it for the water/energy savings.


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RE: hot water on demand systems? good or not?

One version will start the pump when you touch metal.

Tankless heaters USED to suffer from frequent descaling needs in hard water areas. I don't know if that's been addressed, but I'm pretty sure it will never be mentioned in any ad unless it HAS been addressed. Just something to check; our water here is probably as hard as muni water can get.


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RE: hot water on demand systems? good or not?

I will have to do more research, but from what I'm reading here it appears we will not need recirculator's in our new house as we plan to have two tankless water heaters. My husband wants to install an additional 50 gallon standard water heater for a "back up" to the tankless. As long as I don't have to run the water for a long period of time to get hot water, I'm okay with whatever mechanicals are in place.


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RE: hot water on demand systems? good or not?

I don't understand how a recirc pump that starts when you tap the faucet is any different from just turning on the tap. The point of the recirc is that it keeps the hot water recirculating through a loop so that the hot water is right there when you turn the tap on. If the pump doesn't start until you tap the faucet, you might as well just wait for the hot water without the pump....unless I'm misunderstanding the option.


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RE: hot water on demand systems? good or not?

Annie, I think when you "tap metal" (or in our case press a button) the water recirculates without coming out of the faucet, so that when you do turn on the faucet after a minute, the water is hot! Here in California water conservation is a big deal so the idea of having all that water go down the drain while you're waiting just doesn't sit right . . .


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RE: hot water on demand systems? good or not?

I'm sure the performance has improved, but our current home has an older recir. system AND the insta-hot in the kitchen.

The insta-hot is amazing. I love it.

The recir. system was costing us over $300 more in electricity a month than the already ridiculous amount we were paying. We turned it off and the electricity costs came down immediately. That's a huge energy drain, and I doubt anyone could make that up with water savings. But it's an older system and I've heard great things about the newer ones. We also have close to 35-40 showers or baths per week in our family, so perhaps we didn't set the system properly when we moved in? I don't know, but I'm not putting it in our new build, that's for sure! ;)


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RE: hot water on demand systems? good or not?

Wow, RHD, did you have the "always on" kind of recirculating pump? I can't imagine a demand pump using that kind of electricity (unless someone is just playing with the buttons all the time).


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RE: hot water on demand systems? good or not?

We are changing our 80 gallon (propane) water heater for a tankless and adding a recirculating pump to the master bath which will be on a timer for a few minutes every morning and evening. It's all going in today, so will have to let you know!


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RE: hot water on demand systems? good or not?

We have a recirc system - no pump, no electricity - and instant hot at all sources on 3 levels. Gravity system.


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RE: hot water on demand systems? good or not?

We were talking about this yesterday in a meeting with our architect, builder and enviro consultant yesterday.

The on-demand system works well at our builder's house. He has a small, 900 sq' 1 story house. His water heater is in the basement, directly below the main bathroom, and next door to the basement bathroom. The kitchen is about 10 feet from the main bathroom. He gets instant hot water. And, he never has the hot water run out because the tank is empty.

Our architect has a large house. It takes a few minutes for water to get from the on-demand system in his house to his showers.

So, given that our house is going to be more than double our builder's house, we could leave the water running for a few minutes until the water gets hot. Or, the enviro consultant suggested a recirculating system, which we could either put on a timer, or a switch in the bathroom. So we'd flick the switch, and water would start circulating from the basement (2 floors away) and if we weren't ready to shower yet, it would go back into the system to be reheated. The advantage of that is that it's not sending water down the drain and into the sewer system. (Wasting water, and possibly energy to heat water that we're sending down the drain.)

The enviro consultant still likes the on-demand system because we wouldn't be heating water that just sits in a tank and may have to be heated many times before it actually gets used.


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RE: hot water on demand systems? good or not?

I see, oaktown....water supply isn't an issue here. Thanks.


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RE: hot water on demand systems? good or not?

2 Rinnais here since 2006, one on the exterior of each side of the house, close to all points of use. 2 masters and powder room supplied by one, 2 guest suites, kitchen and laundry supplied by the other. In 8 years DH has performed maintenance twice, as a precaution due to our very hard water. Simple job, disconnect, circulate white vinegar, flush, reconnect.

The heaters work as advertised, endless hot water, on demand. We love not having a tank taking up real estate and leaking heat into the house. We love only heating water when we need it. We love the flexibility; it doesn't matter if there are two people living here, or ten, there is never a problem providing abundant hot water.


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RE: hot water on demand systems? good or not?

I miss my on demand at my last house. It never ran out of hot water so it allowed long baths, multiple family members can bath without having to wait for the hot water tank to heat.

I will install an on demand as soon as the newer tank water heater (I did not choose) on my newer house gives out! And I also love my instant hot at the kitchen sink for on demand coffee or tea temp water that is safe to drink.
lafdr


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RE: hot water on demand systems? good or not?

We chose a tank heater in part because having 50 gallons of circulating fresh water always stored in the basement without having to do anything extra seems like prudent and easy disaster preparedness.


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RE: hot water on demand systems? good or not?

I wonder if that is a wise strategy though, I've always been told you're not supposed to drink the hot water coming from the tank heater. Heated water that stands for a while is a source of all sorts of bacteria.


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RE: hot water on demand systems? good or not?

Hot water recirculating pumps are very good. The on demand ones are the most efficient as there is no unnecessary energy waste during the times that hot water is not needed. Look into the Demand Hot Water Pumps as they are proven and have been tested by the DOE. They cost about $1.00/year in electricity to run as they only run when hot water is needed by the user. You push a button and the pump recirculates the cold water back to the water heater while drawing the hot water from the water heater to the pump location. When the pump feels a 6 degree water temperature increase, it shuts off so there is no hot water in the cold water line. The C1-100 is a pump that will service a home that is under 3,000 sqft. These work with either conventional or tankless water heaters and is the only one that doesn't void the tankless water heater warranty.


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