wrote in message
...
wrote:

I am building a new home in SE Virginia...

...a good climate for solar heating with a sunspace. NREL says 1080
Btu/ft^2
of sun falls on a Norfolk south wall on an average 39.1 F January day with
a 47.3 daily max, so the average daytime temp is about 43. A single layer
of
polycarbonate plastic sunspace glazing would gain 0.9x1080 = 972 Btu/ft^2
and lose about 6h(80-43)1ft^2/R1 = 222, for a 750 Btu/ft^2 per day net
gain.

Nick

So do you recommend gas or oil along with the solar?