I have an open rack. I think it works just the same. A closed rack may offer a little bit of insulation, but it's nothing drastic. The only thing that an enclosed rack truly offers is a sense of security. If you don't want to bother with hides, then an enclosed rack is best. Since mine is open, I offer all my snakes hides in both the back and front. They seem to do well. My temps and humidity stay pretty constant.