I have a 10x20 shed. It has a chipboard floor, and below that is about 8" of open space, which wind will blow through. If needed, I can close it off - but I cannot insulate it. My main concern is not with heating the room, although that would be a nice benefit. By far, my concern is with cooling it. I can add an A/C, but I am using R11 insulation on the walls. I can put R11 on the ceiling also, but again - I cannot insulate the floor. With all of that considered, and considering that heat rises, and R11 is such a low value - would I be better off to *not* use an A/C, and to leave the ceiling without insulation? And any other tips or tricks are appreciated. Thanks!