Back in the early 1980's during my hippy phase, I built a passive (thermal mass) solar heated house on my parents farm. Did everything myself except the masonry (which I did the grunt work for lifting blocks and mixing mortar) and the central electrical box wiring. 10 patio door windows faced south, one electric baseboard heater in the laundry room, and a great wood stove kept me warm. It was built into a hillside up to the loft level in the back. 20x30 footprint, 12x30 second floor loft. I even made my own beams, cutting down trees on the farm and using a chainsaw jig to square them up. Good times, but I got bored after a few years and went back to school.