Well it also determines on whether or not you use plastic or glass. If you are using glass then you need to put a towel or something over the screen so that the himidity will stay high enough. And by doing so your "cool" side will stay much warmer. And if your snakes are kept in a room by themselves, then you can put a space heater in there to keep the room a little warmer, just make sure you keep the door closed. I got a space heater for $35 and it has a thermostat so it cuts itself on and off when needed to keep the room at 80 degree's.