Comments for blog.limedaley.com/post/hot-water-recirculator-is-a-waste-of-money

Comment #2115

2025-11-09T03:02:30Z

I've been working on a solar hot water heater that Jonathan brought home from work when he took it off a customer's roof.

It looks kind of like this one.

And so I've been thinking about measuring the temperature of the water and what to do if there ends up being excess heat, and one solution I thought of was this post and run the water to the faucets, which would draw off a little heat, though probably not too much.

But, back to the original point of this post, I think one with a button (or maybe a nifty hand-wave switch that I picked up for fun, but didn't end up using on the project I was planning) might solve the problem, because then you tell it you want hot water before you go to the bathroom, and it is ready when you are.

So, now I just need to find some cheap circulator pumps since the typical boiler ones are probably overkill.

Comment #2114

2018-08-17T12:47:09Z

I purchased the kind that has a black by-pass valve under the sink. I should've done research first. If I knew it would make me wait for cold water I would not have purchased. Why do manufacturers play ignorant and fail to mention that obvious problem. The instructions says that upon hot water arriving at the sink, the valve closes. So, am I to believe when hot water is not at the sink the valve is wide open? After returning it to homedepot we went with ready temp hot water circulator. This system uses a gate valve that opens when the pump starts and closed when hot water reaches the sink. We're using both timer and on demand pushbutton because the kids are on a different schedule.

Comment #2113

2014-03-23T17:53:19Z

I've been wondering if we switch to a solar hot water system that then I'll hook up something - there are some faucets that I've stopped using the hot water valve because the water doesn't get hot by the time I'm done with it...

Comment #2112

2014-03-05T20:05:58Z

after reading comments on different sites, seems the on demand type units w/b the best. You want hot water push the button and it arrives shortly. still a slight wait, but it works and saves energy.

Comment #2111

2014-02-01T11:27:51Z

Yes, that would be fine and I've wondered about a motion detector, which would be even better. I still don't like the two pipe version where if you want cold water you have to wait for it to cool off, since the normal method of installing this circulator is with just using the existing two pipes (which I get that it is much easier in most cases to not install a third pipe).

If the pumps didn't cost so much I would run a third pipe and then setup the two bathrooms to run on one pipe whenever someone walked into either bathroom, since they are right on top of each other, it wouldn't waste that much water, and save the cost of a pump.

Maybe someday I'll find a cheap pump - I should have saved the pump when I replaced my furnace.

I also have been looking around for a small (110V) electric instant water heater, but I can't find any that have longer than a 12 month warranty, so they must be pretty prone to breaking.

As for Kent's comment above, I'd think that heat tape that only needs to heat the water to a minimal level would be cheaper than using your piping hot water to circulate around and re-heat constantly.

Comment #2110

2014-01-25T19:00:02Z

How about putting the recirculator on a timer (like a christmas light timer), so it only turns on when everyone takes a shower or bath? Would that work?

Comment #2109

2013-05-28T19:01:36Z

I have a simple recirculator that just moves the hot water into the pipes at a certain time in the morning. I have it set so it does it just before I take a shower in the am. It doesn't use any noticable amount of electricity and I no longer have to run the water for five minutes to get to the hot water. I'm quite happy with it.

Comment #2108

2013-01-26T15:05:58Z

We're putting one in for a different reason. Our guest bathroom and laundry room are on a long branch that runs thru an unheated crawlspace. When it freezes up and cracks the pipes, it's a mess to fix, lying on your back in the mud. I put in heat tape.... Until it failed without any way of knowing about it!

So now I'm putting in a recirculator to keep both lines warm in the winter. We can always turn it off in warmer weather.

Comment #2107

2013-01-18T14:27:07Z

Yes - I've been wondering how things change with a solar hot water heater.

We will be getting one sometime this year probably, just need to stop pouring money into the sieve, I mean the house.

I was reading somewhere about a solar heating system, and the guy said how great it was to have the windows open in the winter - more fresh air, etc. and since the heat was "free", he could do that.

Comment #2106

2012-12-29T01:39:19Z

This system, along with a solar water heater works great!

Comment #2105

2012-09-13T11:35:53Z

hmm - that's interesting. and i wouldn't think it would take that long, it's probably fast to pump the water up. maybe a motion detector would work - that'd be neat.

Comment #2104

2012-09-08T23:54:19Z

Wouldnt it be simple to just put it on a switch?? this way just turn the pump on a few minutes before you shower and you would save all that wasted water.?

Comment #2103

2012-05-25T17:07:35Z

My issue isn't that it doesn't provide hot water. It is that you now have to wait for the cold water to cool down.

The fire hall in my township just got a gas instantaneous heater, and I've been waiting to see if the gas bill noticeably changes.

Comment #2102

2012-05-21T17:00:37Z

Say what you will about the Watts Premier product, but I like it. I use it in timer mode for the peak times. I find it to be an excellent product and met my needs. hot water now, vs waiting up to 30-50 seconds on hot water.

Comment #2101

2012-03-09T05:08:19Z

The instantaneous electric hot water heaters are not worth your time. The amount of electricity that they require to heat the water is absolutely amazing. I've also found that the electronic components in them don't hold very well.

Comment #2100

2012-02-12T15:19:44Z

You have a point, but the issue is that whatever temperature you set it at, both the cold and hot water pipes will have the same temperature in them. It might be the case that you could set the temperature at a low enough temperature that it is tolerable for either cold or hot, but I'm not sure.

As far as backflow, the issue isn't that the warm water from the hot water pipe goes into cold water pipe *while* you are using it, but rather the entire design is that when you aren't using the water, the hot water gets too cold, and it sends it back down to the hot water tank via the cold water pipe. (though it seems that the recirculator could turn on while you are using the cold water and direct warm water directly to the cold pipe until the water warms up enough and it then shuts off, in which case it would take twice as long as normal for the cold water to get cold - but maybe they watch pressures at the inlets or outlets to decide if you are using the water or not, and prevent that issue. The first issue is not preventable in a two pipe design).

If I ever pipe in a system from scratch, I might do the three pipe system, or think about an electric instantaneous heater, though I was just looking at them again this morning, and the power requirements are so high in order to get a reasonable amount of degree of rise, so I'm not sure if they really work anywhere I've ever lived.

Comment #2099

2012-01-03T16:44:22Z

---"So, now you waste warm water and time as you wait for the cold water to cool down."---

I wondered about that. But as I understand it, the systems that work properly do not allow a backflow from the hot water line, when using cold water. And while the water sitting in the cold water line might not initially be as cold as before, it would seem that would only be an issue if one needs water colder than "luke-warm" - which I never do. Setting the recirculator hot water temperature setting too high, would mean hotter water (than luke-warm) in the return line (cold water line) but that's manageable. No need to have it at maximum - at least not for me. So warm water returning through the cold water pipes shouldn't ever be really hot. And I can live quite comfortably with a cold water line that initially delivers luke-warm water and a hot water line to my shower that initially delivers skin comfortable hot water - although not steaming hot water.

Comment #2098

2008-08-22T17:04:41Z

The system should work such that it doesn't pull hot water from the hot water side unless the temperature is low on the hot side, in which case, it would run whether or not you had the cold water running.

I talked to a guy at Home Depot, who said his solution was to run a third line from the hot water side at your sink and plug it into the drain on the hot water tank. No pump required. He said he had done it a couple times, and it "just worked", something about feeding by gravity. I was skeptical, so he said look it up on the internet.

For us, I was replacing the pipes anyway, to get rid of the clogged up pipes (mostly iron) and ran the hot water line in a shorter direction, so the water gets hotter quicker than it used to - we'll have to see if that is enough.

Comment #2097

2008-08-22T08:27:41Z

I know the feeling, we too ended up taking back our Grundfos system which is just like the watts premier you spoke of. We were suspicious after reading the instructions over. The instructions said something about testing to make sure the comfort valves are working properly you should shut off the cold water supply and open the cold water faucet. If water comes out the cold water faucet then the valve is working properly. After reading it a few times I finally understood the process. The black by-pass valves that install under the sinks allow water from the hot side to passover into the cold side until hot water closes the valve. My problem with the Grundfos UP15 and the Watts Premier is the by-pass comfort valves they use. When installed there was just no way to get "only" water from my cold faucets. Even with the system off, using our cold water faucet pulled water out of the hot water lines and cold water lines. The thought of my water heater waking up whenever I used my cold water was too much for me to accept. The only one that worked for us was Readytemp by Temtrol. A bit pricey but nowhere near the cost of installing a tankless, so we kept it.

Comment #2096

2008-08-19T18:21:53Z

Waiting for cold water reminded me of our system. In the winter we wait for the water to run hot, and in the summer for the water to run cool. Often in the summer I can take an entire shower using "cold" water alone. This is why we have a milk jug at the sink to capture some of the water that is wasted in the waiting.