Nick You might "open windows" with a thermostat and an exhaust fan...

If I'm right about that 800 ft^2 of glass, and if 400 ft^2 of it is
passing
sunlight, then he's getting 332k BTU on those February days you
quoted. While the sun is up, he'll lose 50k BTU through the windows.
Assuming he loses a good chunk elsewhere and has no significant
thermal storage he'll need to vent over 1000 cfm at 80F (from outside
55F). Not exactly an 8" NuTone bathroom fan.

Nick My advice: forswear thy fossil fuels and improve the solar
Nick performance. It's easy, with high-school physics and simple
Nick arithmetic.

....and many, many tons of water.