Tankless Water Heater for All Needs or Hybrid System?

Brando

I was thinking that I would install a tankless water heater for the floors and keep my gas-powered tank water heater for the sinks and showers. The contractor I interviewed recommended that I switch everything to tankless. He is recommending a Navien tankless condensing water heater, which I think is one of the more expensive ones. I am concerned that a fully tankless system may not be rated for potable water. Any thoughts on the pros and cons a fully tankless or hybrid system would be sincerely appreciated.

Jamie Hall

Well... considering that no water heater is designed to be a boiler, which is what you want for your floors (I assume you are talking radiant heat in the floors?) I wouldn't do either one.

If the loads worked out right, I might look at a combi, with completely separate operation for domestic hot water and heating, and both designed for and fit for the purpose, or a separate small mod/con for the floors and a separate -- possibly tankless, if you flows are in the range they can handle -- for the domestic hot water.

hot_rod

You don’t want to combine heating water with potable water". So two tankless?
Perhaps he was suggesting a combi which can safely do heating and DHW.