I too bought a CB 5036 to heat a house about the size of yours. I started out wanting the Shaver, but am glad I went with a local guy. I looked long and hard at the
Proctor and Maine (spelling ?). I really liked the set up on it but the $ were too much. I have radiant heat in the basement and love it, got it set at 70 and it's a very comfortable heat. The up stairs has baseboard, and the dom h/w is off an indirect hot water heater. Using the electric h/w heater would be cheaper for you since you have an alternate solar heater for the summer. My under ground pipe is 135 feet, I had to snake around a tree and patio. I spent almost 2 G on the pipe and loose almost no heat and the return is usually quite hot coming back to the boiler. Like they all say, spend it now or spend it later. Do your homework and buy quality material, you'll find a set up that will work for you.