We are building a house that is about 2200 sq ft. The kitchen and utility room are at one end and the bedroom/bathrooms are at the other. We want to consider either installing two hot water heaters(one in each end) or a circulating hot water system. We would appreciate receiving any advice and experience to help us in this choice. We are told by our builder that the original cost is about the same. Thanks
Dear jplasater:
Two hot water heaters is two times as many vessel to replace in "ten years", and twice as much damage when/if you don't catch the first drops *immediately*. Additionally it is twice as much surface area to radiate dollars away.
Make sure the return line has *lots* of insulation. Add a timer if you like, to only prewarm the "far" water supply an hour before you normally use it. That will help reduce the radiant losses from the tube over a period of a day.
I'd definitely keep all the "complex stuff" in a place that will be easy to service, and can duct major water leaks away from walls and carpet. This is what hotels do.
You could additionally put an "instant" water heater in the far showers, but this won't help with getting hot water to a far sink.
David A. Smith
There's another choice: a central instantaneous (gas) water heater. There are models on offer with 25 year warranties - better than the ten year life you might get out of a 30, 50 or 100 gall storage heater.
Brian Whatcott Altus, OK
I've got a similar laid out house that I'm getting ready to re-pipe with PEX.
I'm sticking with a single WH near the laundry& kitchen. I going to run a timer & temperature controlled hot hot water loop to a remote mainifold near the bathrooms.
I plan to well insulate the loop.
cheers Bob
Dear BobK207:
The loop volume will be cold water as the pump turns on. Be sure the "return flow" is delivered mid-tank, either through a side-port, or a downcomer. Hot water tanks tend to stratify, and you need to enforce this, or else you'll get hot/cold oscillations at the outlet while the pump is running.
The return loop does not need to be full sized pipe, this will help minimize this volume. Just allow enough flow that the pump does not fail.
But you probably already thought of this! ;>)
David A. Smith
Thanks
I did think about reducing the return line size but only to 1/2" PEX since my inventory of tubes & tools will only be 1/2" & 3/4".
I'm torn between 3/4" & 1/2" to service the remote hot manifold by the bathrooms. I'm currently leaning towards 3/4".
This might be overkill but 10+ years of restricted galv steel has me a little crazy for high flow hot water. I'm considering running the PEX in the attic rather than the crawlspace. I'm getting a little old for crawlspace work. I plan to insulate the tube, plus an attic in SoCal doesn't get that cold.
My plan for the return loop was just dump it into the cold wate inlet & maybe add a check valve.
cheers
Dear BobK207:
If you leave your thermostat low, OK. If you keep it over 120 deg F, you can probably go with 1/2". You usually temper the water flow with cold (which makes up the volume), and if you no longer need to waste water until the hot stuff arrives...
100' of 3/4" ID pipe is about 4 gallons 100' of 1/2" ID pipe is about 1 gallon.It is your money. You know what you are comfortable with.
Excellent solution!
David A. Smith
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