I'm looking at the possibility of doing a 40' x 70' pole building home in the next five to six years and am sold on the idea of radiant floor (in the slab) but the question is what to feed it with. A friend of mine simply uses a tankless propane water heater to power his, and his home is very well insulated (R-30 walls, etc...), but I'd love to primarily utilize wood and solar and really only rely on the propane for when we're away for extended periods, etc... Obviously storage is key to this proposition, but how complex does the system have to be (electronics, controllers, etc...) in order to be relatively "hands off?" Ideally I'd like to only think about it in terms of firing the boiler every couple of days or so during the heating season in order to top up the storage. Obviously the solar will be dumping heat into the storage whenever the sun is shining and the propane will be there for whenever the storage is not adequate to heat the house and/or the DHW. Does anyone have any good links to schematics of a system that utilizes all three? I realize that there's a lot more to it in terms of sizing, etc... I'm just trying to get a handle on how to get each heat source to work in harmony at this point.