Does anybody use an indirect water heater?

[btuser]

You're not losing the heat when it flows into another tank. That's how indirect tanks work in the first place, by moving heat through a heat exchanger. 70-90% of the standby losses come from a.) the boiler and near boiler piping. b.) When someone turns on the hot water and re-heats the piping to the emitter, generating a loss as that water returns to ambient temp. My indirect loses about 1/2 degree per hour, which comes out to about 170 btu/hr, which is squat. My boiler loses about 500-700 btu/hr, and that's considered really, really good for a high mass system. It still cuts down my system efficiency from around 90% to a more sobering 60-70%, so for the Summer months a tankless would win-if I had nat gas. For the 4 months/year when my outdoor temp is above my ambient temp this is a waste, otherwise it goes into heating my house and I'm figuring about 80% for hot water.

Tankless heaters are better than a standard, open flue gas water heater but I have my doubts about their longevity and real efficiency, especially in hard water areas.

 

[begreen]

Is solar a possibility for supplementing your setup?

 

[btuser]

I'm going to try a drain water heat recovery first. If that plus my constant bitching about the hot water can drop the overall usage to 100 gallons/day, I'll be in the market for a solar setup. I'm already looking for the tank. I I can score a large 80 gallon + dual coil indirect, or a 100 gallon single coil I'm going to take it and figure out what to do with it later. I'd favor a single large tank with dual coils simply because I don't have the room, but its looking more and more I'm going to use a single coil tank connected to solar as a pre-heater to the main tank that will remain connected to the boiler. The problem I see with this would be the necessity of the boiler still firing unless the solar tank was in the 140f and up range. I'm thinking of digging a hole/box against my basement, placing the tank there and insulating with foam board to keep out moisture. I really don't have any room where my boiler is now. Right now hot water cost me about $2.50/day, so its a hard sell to the right side of my brain when the proper solar setup would run me $7,000.