URGENT: Recirc pump -Yay or Nay?

eleenaSeptember 26, 2013

This is a partial X-post from Plumbing but this forum moves faster than any and I need an answer "yesterday", so I am asking for your indulgence. Plus, I learned about recirc pumps on this board. :-)

Our water heater is installed far away from the main point of use and it takes *forever* to get hot water in the kitchen and MB. After learning about recirc pump on this forum, I had no doubt I wanted one. But my plumber says the house is not set up for a recirculating pump and there is only one kind that can be retrofitted, which would run me ~$1K to install.

If I decide I could live with running water for several minutes ever time I need it hot, is the upfront cost worth it compared to saving on water usage?

Anything else I need to consider?

Yes, I know about water conservation and I do want to be "green" but I have spent about twice of what I had planned on the kitchen remodel, so I'm hard-pressed for cash. :-( Plus, I can use that running water for items that require hand-washing.


Thank you!

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Get a point of use water heater instead.

Recirculators are terribly inneficient because you end up heating all those pipes constantly. From an insulation/efficiently perspective, you're effectively increasing the surface area of your water heater.

Kitchen sink is ideal place for a point of use water heater since you rarely need more than a few gallons at a time.

Here is a link that might be useful: point of use water heaters

    Bookmark   September 26, 2013 at 7:32PM
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His quote is correct, +/- $200.

The math is easy:

Look at your total annual water bill. Take your best guess what percentage is used in the kitchen & MB for hot water (minimal).

Now divide the $1000 by that and that is how many years it will take you to break even on the water you "wasted".

Unless you just graduated college, you'll be dead!

Another idea is the European style "instant" hot water heaters. You can put a mini on your kitchen & MB run. They come on with gas or propane and heat pretty quick. Not $1000, but it will still be years to break even.

    Bookmark   September 26, 2013 at 7:35PM
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We have a tankless with a builtin recirc pump. It is by Navien. Would not be without it especially as water has to travel a long way to the bathrooms and kitchen.

    Bookmark   September 26, 2013 at 7:50PM
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In our part of California, where lack of water is a real issue, it is part of the building code.

    Bookmark   September 26, 2013 at 7:59PM
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I can't speak to the extra cost since we have always had a recirc pump since owning a home. However, what I can attest to is how much I love it! I can turn on the faucet to wash dishes and immediately have hot water, quickly jump in the shower, etc. It has definitely become a luxury that I wouldn't want to live without.

    Bookmark   September 26, 2013 at 8:08PM
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Sophie Wheeler

All you need is a small tank heater under the sink that is fed by your hot water line. When you turn on the hot water, it comes directly from the tank, and then the hot water from your tankless will replenish the lost water from the tank and you will have all the hot water you need.

    Bookmark   September 26, 2013 at 8:10PM
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Thank you, everyone!


I have 4 sinks (2 in MB and 2 in the kitchen), one shower, a DW, and a washer with the "long wait" problem.

Do I need one for every sink? That might run more than $1K or about, no?

How do I go about the shower and the laundry?

I have 2 hours to decide. Any other thoughts?


    Bookmark   September 26, 2013 at 8:42PM
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I wanted a recirc or instant heater for our bathroom but the cost outweighs the need- someday.

    Bookmark   September 26, 2013 at 11:06PM
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What Holly calls a "small tank heater" is the same as the point of use water heaters I mentioned above. And yes, you need one for each point of use.

    Bookmark   September 26, 2013 at 11:53PM
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Don't rush into this decision. We assumed we would get a whole house tankless system. During our visit to the plumbing store who we planned to purchase from, they unintentionally talked us out of it. Yes you will have continuous hot water once it gets going but you will still have to run the water for a while to get to the warm water. I then talked to a friend who had a whole house tankless system and was told she hates it due to the long wait time.

Instead we installed a double hot water tank system. One (gas) tank preheats the water to 90 degrees and then it goes into the 2nd tank that bring it up to 120 degrees. We do have a slight wait time for the upstairs bathroom but its reasonable compared to the 5 minutes we were told it would be with tankless.

I am not putting down tankless systems. There are many variables including whole house vs point of use. What I am saying is that you need to do your homework and make a decision that works for your house.

    Bookmark   September 27, 2013 at 8:28AM
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I agree with the point of use heater or an instant hot. Although, maybe you dont need one for *every* location. Only the ones you use the most times throughout the day. It's ok to wait for hot water at the shower because that is only once per day. But the kitchen sink is used many times per day so wasted water every time.

We have a whole house tankless water heater, and it was 100% the right decision for us. Our heater is centrally located up near the ceiling in a closet in the middle of the house so it is short run to each location. Hot water arrives to all locations in seconds. We also have our house plumbed with a water manifold that is right under the heater which helps, I would imagine. Another reason tankless was right for us: our house is a vacation rental home that sometimes has 4 people, sometimes up to 26 people staying here, and other times is empty for weeks at a time. How big does the water heater need to be sized to provide hot water for 26 ?!?! Why pay to maintain hot water temp when there is noone here ?

    Bookmark   September 27, 2013 at 8:48AM
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You can put the recirculator on a timer (only on during the day or whenever you're home using hot water) or motion sensor (runs when you enter certain rooms).

While this doesn't help with the cost of purchasing and installing it, it does make it more efficient and help you get to a breakeven point sooner.

    Bookmark   September 27, 2013 at 11:55AM
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We're confusing two independent choices here. The choice of tank vs tankless for primary (aka whole house) water heating won't impact the wait time for hot water.

There's two ways to reduce the wait time for hot water: (1) install a tank or tankless recirculating system or (2) install heaters closer to point of use.

If you're only concerned about the kitchen, then electric point of use heaters are totally adequate by far the most economical. But if you really must have instant hot water everywhere, including bathroom sinks and showers, then a recirculating system or multiple tankless heaters around the house are likely a better option. Point of use heaters definitely won't work for the shower, for example, because the only hold a few gallons.

    Bookmark   September 27, 2013 at 12:26PM
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Annie Deighnaugh

We installed 2 tankless hot water heaters. One serves just the M bath on the west side of the house. The other serves the laundry, PR, kit and guest bath on the east side of the house. Part of this is for the wait time...part of this is because I told DH I didn't care what it took, I wanted to be able to take long, hot showers and not care if someone in the house flushed a toilet or if the washer was on the rinse cycle. I lived for 30 years with cold water shocks in the shower, and that was enough.

I was against a recirc system because they are so wasteful of energy.

    Bookmark   September 28, 2013 at 10:27AM
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Sophie Wheeler

The METHOD of hot water production has very little to do with the amount of time it takes to reach the fixture. That has to do with the LOCATION of the hot water production. If you put any type of water heater 60' across the house, you've got 60' feet of piping to purge the cold water out of before it gets to the fixture. And it will have that regardless of how that hot water is produced.

It all goes back to the primary DESIGN of the plumbing system, and where you locate that water heater. Some place central is ideal, or, if the home is especially large, two points of production can sometimes make sense. That has nothing to do with tanked vs. tankless though.

It's only when the system is poorly designed that you have to institute stopgaps like point of use or recirculation loops. Either of those options costs additional for the initial installation and has ongoing energy consumption costs that can be prohibitive. You have to weigh those costs with the cost of simply purging the cold water from the pipes and that inconvenience.

In Western areas where water is scarce and costs are high, flushing that cold water down the drain may be more cost prohibitive than the energy wasted by recirculation pumps. In Eastern areas, especially those who rely on electric, the pumps may cost a lot more to run than living with purging the line. It's a cost. vs. benefit analysis for your location. And, it's also a personal analysis of how committed you feel to being "green".

    Bookmark   September 28, 2013 at 10:46AM
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