Well, the doors that houses have to garages are the same as doors to the direct outside, so, frankly, I don't see a big deal about it! For example, I mean, there aren't garages that are attached to my sliding glass doors that go to our backyard in or basement, neither is there a garage attached to my front door and so on. I guess just closing the garage door isn't something he's worried about. OR maybe he's just trying to air it out. A garage is the same as a carport, except there's a garage door and an additional wall or two. I'm sure it could help SOMEWHAT with the cold to close it, but I don't think it is a big enough difference...