If you are using an enclosure with straight enough sides you can easily "wrap" or mount sized cardboard or styro sheets on the sides to act as an insulator and ensure you are not using an open-topped solution (like a wire-screen top). If you are mod, it using the duct-tape or contac paper. Best approach in the screen situation is to cover the inside (bottom) so you can also mask that surface this helps prevent your snake from getting rub wounds on the nose (we've all seen them straining upward and testing that surface with thier noses and they often have to make contact to help balance or stabilize themselves).