I'm glad you pointed that out. I'm in central Indiana and have the whole cold winter ahead of us yet. I have my tubs set up currently as simple, individual tubs with UTH for each, on a shelf. THey're in a small spare bedroom (about 11ft x 13 ft) and I keep the door shut and run a Lasco electric space heater to keep the ambient temps about 76-77. I am hopeful that an enclosed rack in that same spare room will add some heating efficiency over what I have now. I only have a couple snakes, and don't intend to get into any large scale racks (else, I'll have to fill the tubs!). So I'm investigating which kind of enclosed rack design (back heat, belly heat) will be the best bet for cold climate where I have to use supplemental heat for ambient temps as it is.