Re: On-demand water heaters
Brian, you can return thru the drain opening.
<font color="blue">it takes a long time to get hot water to my upstairs bath now. </font color>
Just remember, that with a loop system, it will cost you more to keep the water hot. Personally, I don't mind waiting the extra minute or so, as opposed to paying for the extra energy and set-up cost.
Re: On-demand water heaters
I'm having a Metlund D'mand system installed in my new home. Basically at the end of the run the hot/cold lines are tied together with a set of tees and a small pump. There is a temp sensor on the hot side. Press a button and the pump draws from the hot side and forces it back into the cold side. When the sensor detects a temp rise on the hot side, the pumps shuts off.
It's not a water heater in itself. All it does is eliminate the water from doing down the drain while the hot side is filled from the water heater.
More information is available at www.gothotwater.com
Re: On-demand water heaters
We built a small (2 bedroom, 2 bath) farmhouse about six months ago. My wife and I are the primary, part time users. We have a 40 gallon electric water heater and even when we have guests (up to 4 additional people) the hot water just keeps coming! I don't know how old your primary residence might be but we were amazed at the advance in the efficiency of this vital appliance. When we leave, we turn the hot water heater off at the breaker panel. The costs have been modest. Best of luck on your construction.