Our house has a hydronic heat system, Warmboard subfloors, double exterior walls, R-60 ceiling, etc... We are installing 6 vacuum-tube solar panels, a small electric boiler, but want to use an outdoor wood boiler for the majority of the heating needs during winter.

There are so many options out there and all claim to be the best, most have efficiency ratings in the high 80's. We would like to heat a 500 Gallon + tank then use closed loop systems (passive in the tank) to heat multiple buildings.

Any suggestions?

thanks,

Sam