Our 6 x 8 has a few gaps - - the weatherstripping isn't designed to come all the way up for some reason -- so there is a gap on each side of the door - and a couple gaps at the bottom of the door also. Cold air leaks around the left side (we are going to get that stick on type of sealant for that - but wondering what others have discovered works well?
Right now I have an egg crate foam mattress hanging there -- but there is still air leaking in.