Yeah, I agree. The losses via windows and sliding patio doors is massive at our house.
My Den has over 100 sq feet of glass.. And, it's on the north side of the house..
But, we are heating it this year. (Plus heating the whole house to 70).
I'm not sure, but I think if it really gets cold this year, we will be burning
about twice as many kW hours as last year..(When we didn't heat the Den much).
The whole idea of using outdoor solar hot-air collectors, in place of regular
windows for solar gain is excellent.
If we had it to do over again, our den would not have a big glass patio slider
and we would NOT have four big 48x48" Andersen sliding windows..
That design must have come from way down south..
I would love to replace that back slider with a regular entry door.
Plus replace at least two of the Andersens with insulated walls..
