Anybody remember the article/discussion in print that discussed different methods to provide warm water to more remote areas of house? One idea (I think)was a one gallon heater at the point of use…..water from main waterheater would reach and mix before all cold water would come out of shower head. I’d like to read details again before I use this idea. One plumber friend says it won’t work, I disagree……..any thoughts?
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There are a number of smaller electric water heaters that run on 120V, from 1-6 gal. We actually have one at work that supplies a sink in a small kitchen area. For your application, I'd calculate the volume of the water in the pipe between the water heaters and then make the remote heater twice that size, so you'd see a slight decrease in the water temp early on in the shower from the mixed cold water in the pipe, but it wouldn't be too bad. I assume that you have already insulated the pipe between the heater and that bathroom.
I'd be concerned that if the point-of-use HWH is only twice the piping volume, you'll be unhappy about the pretty big temperature flucuations at the fixture. Not a problem for washing hands or doing dishes, but pretty uncomfortable in a shower. Even a few degrees difference make a shower feel too hot or too cold.
The best solution is a circulating, insulated loop on a timer. The occasional time that you take an untimely shower, it will take a minute or two to come to temp. Most each morning, there will be instant hot water in the wall for sink and shower. And you don't need any extra vloume for a small HWH.
I'd only do the 1 to 6-gallon HWH for point of use without a shower. A half bath with sink and toilet, for instance.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Thanks for input.....been advised by others as well that fluctuation in temp may be a problem with 1 gal. heater for bath with shower. Also alittle cold water down the drain is cheaper than electric to keep it heated or keep pumping in a loop. Back to drawing board...looking for a better centralized location for the main water heater.
Have you looked into a small recirculating pump?
http://www.lainginc.com/instant.htm
I have installed a few of these, and the customers rave about them. For power, they just plug into an outlet.
-Steve
Edited 4/17/2003 7:20:02 AM ET by steve-o
I followed the link but could not find the price or where to buy. Are they only sold in plumbing supply houses? Thanks
You can buy the Laing Autocirc unit at Home Depot. The price is about $220 if I remember correctly. It works very well.
Actually I have done this a lot, but with three and five gallon wall mount electric units. No fluctuating temperature and the stand-by loss is so little it probably offsets the wasted energy and water without it.
So you did not notice an increase in electric bill? That is good news, got any recomendations on brand of wall unit heater or web sites I might visit?
From an energy standpoint, assume the small recirc pump motor is 85% efficient. That means that 85% of the electrical input to the motor is converted into mechanical work, and that work is all happening on the water in the loop. Thermodynamics being what they are, the work that you are doing by circulating the water in the loop ends up heating up the water. So you are in effect displacing some of the load from your main water heater.
Mind you, the work that the pump is doing on the water is very small compared to the size of the main water heater burner (or heating element if it's electric). But still, all the circ pump energy is not wasted. And if you put it on a timer that only circs in the morning before shower time, you aren't running it that much anyway.
This type of circulating pump is very common in large apartment buildings, hotels, etc. I think the slang name is rat race pump. Usually controlled by an aquastat. If the water is moving anyway due to fixtures being used, the pump is not necessary. When no fixtures are in use, the water temp in the loop drops and the pump turns back on.
Also, insulating the pipes between the shower and the water heater will not do any good, unless you are taking showers say once every hour. Even the most insulated pipe will cool off over night, so you still have to run for a while to get out the cold water. Now if you are running a circ pump all the time, then the insulation is a good idea. But it won't make a difference if the water is just sitting there in the pipe.
I would go for the circ pump over the separate water heater from an elegant solution point of view, but the elegant solution is not always the installed solution ;-)
my $0.02.
>Also, insulating the pipes between the shower and the water heater will not do any good, unless you are taking showers say once every hour. Even the most insulated pipe will cool off over night, so you still have to run for a while to get out the cold water.
I'm not sure, I thnk I remember someone saying tat the insulation was to prevent condensation on both hot and cold pipeing.
SamT
I can't think of why a hot water pipe would sweat. Condensation only forms when the surface temperature of an object is less than the dewpoint temperature of the ambient air. Since the coldest the hot water pipe is ever going to get is the ambient air drybulb temperature, it shouldn't ever be cold enough for condensation to form unless the space is at 100% RH. And if it's 100% RH inside, you are going to have condensation everywhere!
Cold water pipes (and especially chilled water pipes in big buildings with chilled water cooling) need insulation to prevent condensation. Regular domestic cold water pipes usually only sweat when it's really humid. But you have to also have a vapor barrier in addition to this insulation, or else your insulation will be ruined when the water gets in. The regular pipe insulation you will find at Home Depot will not prevent condensation on cold pipes unless you tape up all the seams really well!