I have a house that if my calculations are correct sits 40 degrees east of solar south. I know there is a lot of what ifs but as a general rule can I still gain some passive solar heat by adding some windows to the southern wall and tiles to a concrete slab floor ? Is the 30 degree max just for heat gain in the summer ? If that is the case then it seems to me that a over 30 degree to the east would be better then a house set westerly over the 30 degree recommendation. House is heated by a wood stove and I am wondering if passive solar would work in the shoulder season and those 50 degree winter days ?