05-06-2008, 11:55 AM
I'm in NC, which has hot summers and moderate winters. When I moved into my current house I found that I had the same problem you describe only worse; I had five single pane sliding glass doors and two skylights in the added room. My solution was to have the sliding glass doors replaced with partial wall with highly efficient windows and an all glass, double pane door. I added high reflective Gila film to the skylights. Since the room was mostly complete, it wasn't like adding an addition. It cost me $4000. It is still a nice sunny room but now it is useful year round.