I read an article about a passive solar, earth berm house in NH - owners went away in dead of winter for two weeks and when they came back it was still 50 deg inside.
Passive solar design also takes into account summer heat gain - different solar angle, shaded windows, insulated roof, light colored roof.
I always figured the best use of solar panels was to run the AC in summer heatwaves.
Converting the heat to electricity is tricky. How would you do it?