Joe
i did pretty much the same thing when i lived in So Calif but with corrugated panels, you are so correct it is pretty much a long wasted space.
i used the polycarbonate but the first winter storm tore them up, so i went to the fiberglass which is a little more expensive but much stronger.
mine was on the south side and got pretty warm so summer was with the door open. i used it mostly for seedlings and a potting shed
http://www.strever.com/FV/FV_0...
