Domestic Hot water(THANKS, It works great now)

Be sure to drain it off every once in awhile, rombi. I hear you about not wanting to deal with your wife if you run out of hot water. Sends shivers down my spine just thinking about it.

I have a sidearm heat exchanger on our electric hot water heater. I shut the breaker off at the panel once we fire up the tarm in the Fall. I discoverered our water heater does use some electric even with the sidearm going, if I don't shut it off at the breaker...maybe it tries to maintain a set temp or cover for any fluctuations in the temp of the tarm water.

Yesterday, I get a call from my wife telling me the hot water at home wasn't as hot as usual...I ask her to take a quick check near the waterheater to make sure there is no leaking. She does and finds no leaks...so I resolve to check things over when I get home from work. Later in the day she calls back to let me know she found the reason for the decrease in water temperature. It seems a certain someone (me) :red: left the hot water on in the downstairs bathroom after I got done shaving at 5:45 in the am....that sidearm continued to heat the water for over 7 hours with only a small drop in temp. The water was still warm just not as HOT as usual. I'm sold on the sidearm set up. Be sure to use a tempering valve to control the hot water temp and prevent scalding when retrofitting older plumbing.

do you have a pump on it also?

No pump on my side arm loop...just sets up a gravity flow loop through the water heater. It works quite well. I try to keep things as simple as possible and it doesn't get much simpler than gravity flow. ;-)