I've had the add-in Laing Autocirc recirculating pump installed under the kitchen sink (farthest fixture from the water heater) for 3 years. I don't bother with the timer as it works flawlessly. Hot water wait at longest is 10 seconds (down from about 45 seconds) and is usually almost instant hot water at that faucet and immediate at faucets closer to the WH.

I charted my electric bill for a year and there was no perceptable increase in the electric bill with the pump installed but water usage dropped dramatically and I realized a yearly water bill savings of a little over $100 with less wear and tear on my water softener, less salt used in the softener, and almost instant hot water at the faucet.

If I was building a house or could easily add a dedicated return line I would prefer that, but all in all the Autocirc one-piece works. It is less complicated than the competing add-in two-piece Grundfos and now Laing has a pump that goes at the water heater with a remote manifold at the farthest sink like the Grunfos.

more info at http://www.autocirc.com/

Do you use electric to heat your water? I'm not at all concerned with energy required by the pump; I'm concerned with energy used to heat the water.

-dan

Hi Dan,

LP water heater not electric. I did monitor my LP bill and tried to keep track of how often the heater fired up. Didn't see any increase in LP usage of note and heater didn't seem to be lighting up any more often than usual. Seems to me that the energy to heat the water would be the same (or close) whether it's always hot at the faucet or you're waiting for it to arrive.

The reality of these retro-fit recircs is that VERY little water is moved. When the temp sensor in the pump opens the valve and the pump starts it runs less than a minute until it senses the water on the "hot" side is hot and then closes the valve and shuts off the pump.

In paying carefull attention (after install) the water heater NEVER fired up when the pump came on so it seems the volume of water being moved is small.

As I said ... if I were doing new consrtuction I'd do the recirc the established way but if retro-fit is what you're after this works, saves money, and saves water. Around here water is scarcer than electricity and not waiting for hot water is really nice. BTW, don't forget that all the faucets closer to the water heater on that line also enjoy hot water right now.

If you have unswitched AC under the farthest sink then the one piece Autocirc is the way to go. If there is no unswitched AC but you have unswitched AC at the water heater then the 2 piece will do the same job.

Just my firsthand experience ... YMMV

I'm not so sure about the "very little water is moved" statement. Yes, they are very low volume circulators. But consider this. In my house as it is now, by the time I go to use hot water, the entire length of pipe has cooled to near room temp. In a retrofit recirc case, you are heating that entire volume of water in the pipe (from heater to farthest fixture(s)) mulitiple times per day, possibly more than once an hour depending on how quickly it cools.

In my house, that volume of water is on the order of a gallon. It seems to me that there is s significant amount of energy in repeatedly heating a gallon of water and allowing it to cool to room temp. No?

-dan

As you plumbing is now, yes the entire run cools. When you turn on the hot faucet farthest from the water heater you are heating the ENTIRE run, BUT with the pump going on only at intervals as required the entire plumbing run is NOT cooled. As soon as the temp sensor in the pump sees the pre-set temp drop AT THE PUMP it comes on. The pump runs less than ONE minute and then shuts off as soon as the temp rises to the pre-set shut-off. You are not heating the ENTIRE volume of water only the coolest part nearest the pump (temp sensor).

How much water could the pump move in less than ONE minute?

I was skeptical too. As a retro-fit there was no alternative. The thing works. Just buy it and put it in.

Dan,

Lowes sells the Autocirc one piece and Home Depot sells the Watts Premier 2 piece click here for Watts pump info

Buy the one that best fits your install. Put it in and see how it works. It just bolts in, no cutting or modification necessary.

See how you like it. If you don't, Lowes and HD have liberal return policies.

The bottom line is that to get hot water to the distant fixtures, you need to fill that entire pipe volume with hot water and keep it there. You are creating a radiator. If the pump only runs long enough to increase the temp at the pump, you wouldn't get hot water instantly at the distant fixtures!

I understand the "just try it" idea, but it doesn't answer my concern regarding energy usage...

It doesn't matter to me whether you buy one of these or not. I have no dog in this fight. I am happy to relay to you what my specific direct experience is with a Laing Autocirc and leave you to your own conclusions.

I care less about the "why" questions then I do about the "how" questions. When I was contemplating the retrofit I got lots of opinions and 9 out of 10 opinions were absolutely wrong. The results of my installing the pump and using it for 3 years plus are in previous post.

If you want a definitive answer try it and you'll know.

In order to get hot water at distant faucets without waiting and without drastic and expensive remodeling and plumbing expenses these retrofit devices are the cost effective answer to the question.

From an economics standpoint you have to decide whether the cost of the device and whatever the added cost of energy (which in my specific experience is negligable) offsets the savings in water usage and not having to wait for hot water at the faucet (which in my specific experience is REALLY nice).

Thanks, Lurk. I didn't mean to seem argumentative about this and I certainly don't question your experience. You have one. I don't. I'm just trying to understand some of the subtleties of these things.

I do appreciate the input!

-dan

Dan,

Sometimes one can't "understand some of the subtleties of these things" and you just gotta finish your beer and take the plunge.

Why wonder when the answer is at Lowes or the HD? The only thing you'll expend is your time ... if you're not happy a full refund is wating BUT, I'm sure you'll be satisfied.

Please post your experience if you choose to try it out.

Dan, you wrote: "If the pump only runs long enough to increase the temp at the pump, you wouldn't get hot water instantly at the distant fixtures!" What you missed, is that the AutoCirc is at the most-distant fixture. So it is ready; and anything in between is equally so.

You are hung-up on the energy loss question. So letÂs resolve it. The fact that the water is already HOT makes it more efficient than running water that was already HOT and has now cooled.

If you are concerned about heat loss when there is no real usage, the solution is to set the timer so that it only supplies HOT water at the times you will use it. If there is no one home for 12 hours of the day, the system can sit idle.

On the other hand, your obsession indicates that you may be in Massachusetts. (I can tell.) In that case, most of the year, the lost heat is re-used for comfort. Bottom line, the total losses are much less than a system not using one. In some areas, new construction codes require the system. There is no dispute.

For a real good explanation, you can find the find the specifics on the websites of the manufacturers.

Pinoke

Observation: if you're using the cold water line at the sink as a return for the not-hot-enough hot water, aren't you then getting this non-cold water out of the cold water faucet when you turn it on???? I don't see how it could be anything else, so what do you do for a cold drink of water? Or do you now have to turn it on and wait for that water to turn cold again???

Hi Frank,

Good question and one that I asked myself before I pulled the trigger on the Autocirc. Taking my own advice, I installed the Autocirc one-piece and had my answer (and hot water) within seconds.

If you turn on the cold faucet immediately after the pump has run the water is only warm and turns cold in 2-3 seconds so "normal" cold water is only 2-3 seconds away.

If the pump has not run in a while the water is cold immediately for all intents and purposes because the cold side has dissipated the water's heat into the cold water in the line, angle stop, and fixture.

Not installing one of these devices, you get hot water in 45 seconds at my house. So, I favor immediate hot water and (in a worst case scenario) cold water in 2-3 seconds over hot water in 45 seconds to one minute.

Looking back over the years the Autocirc has been running it has been trouble free, instant hot water is addictive, and I can not see any increased cost in the pump operation or heating the water. YMMV but I don't think so.

BTW, my Autocirc is still going strong. I've actually gotten to the point where I don't think about it. Went to a neighbor's home the other day, same design and plumbing as mine. Waited (it seemed like) a few minutes for hot water from the faucet.

One can sure get addicted to instant hot wateer :)