Portable electric water heater attached to house hot water line?

Just a little background. I have a pool house that I installed a kitchen sink with hot and cold water. The pool house is supplied with water by means of a pvc pipe running underground to a sillcock about 30' away. The pvc pipe is attached to the sillcock with a short piece of garden hose (all threaded joints). Under the sink cabinet in the pool house I have a Titan (made in Italy, bought at HD) 2.5 gal electric water heater to make the hot water for the sink. The pvc supply pipe has a tee fitting with one side going to the cold side of the sink and the other side going to the heater and then to the hot water side of the sink. The sink drains into a septic tank 20' away. Every year in the late fall, I take the portable water heater out, disconnect the garden hose connector, and drain the pvc pipe. I also take the sink trap out. Over the NY winters, I store the heater in my attached garage.
Now, for my question (finally!). I have a half bath on the opposite side of the house from my propane water heater. Everytime I need hot water there, I have to let the water run for a few minutes before it gets hot. Can I use that electric water heater under the 1/2 bathroom sink feeding from the house's hot water line? In other words, rather than having the cold water line going into the heater, it would be getting the water from the house's hot water line. I doubt whether we would ever use 2.5 gals of hot water at one time there, so the hot water line coming going into the heater would probably never be really hot. This would be just for the winter months when the elec. heater is just sitting idle in the garage. I can't think of a logical reason not to do it, but maybe someone else has done it, or knows why it shouldn't be done. I may not install the heater anyway, but if I get ambitious (or really pissed off waiting for hot water), I'd like to know beforehand.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
willshak wrote:

Hmmmmmm I'll bet there won't be any energy/efficiency savings (electric heat vs propane). I think I would be leery of any temporary (hose) connections under line pressure in a finished part of the house. I'd pass on this one...
Jim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Speedy Jim wrote:

I'm not concerned about energy savings, just the waiting time for the hot water to arrive from the house water heater. Besides, I'm wasting electricity having the well pump replace the water running down the drain while waiting for the hot water to show up at the faucet. The water fittings under my 1/2 bath sink are connected to the faucets with flex tubing. We're only talking about disturbing the hot water tubing twice a year, which is the same frequency that I install and remove the flex tubing under the pool house sink.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Check out REDITEMP. I had one and it worked well after I changed the operating procedures. I removed the time clock and installed an icecube timer set for 2.34 minutes. I would push an button on the wall like an door bell. Then the pump would turn on. It sucked hot water and pushed back into the cold side. The timer was set for the longest time I needed to get hot water. There are lots of recalculating pumps out there that all do the same.
As for the garden hose your asking for problems. You know garden hoses are not really pressure rated, AND not for potable water. (drinking)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
SQLit wrote:

about using what I already have in the manner I described.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It will work. We have a small heater like that in the breakroom at work. It is fed by city water, but the pipes pass through the boiler room on the way to the break room. We are feeding the hot water heater with water that is sometimes probably hotter than the heater would heat it. Unlike you, we have to let the cold water run for a time to get cold water. Ed
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If you use that little water, then I don't see what advantage using hot water for the supply to the electric gives you. The water coming into the electric will be water that's been in the pipes, and will therefore be cold. And the water coming out of the main heater will just sit in the pipes cooling, so you're not saving any energy at the electric, and you're wasting energy from the other (gas?) heater.
If it's just for the sink, why do you need hot water there, anyway?
--Goedjn
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.