If you have open racks you can get blue backed foam panels from home depot and cut them to close the rack in. It will hold the heat. I have freedom breeders wich ate open racks but i keep my snake rooms heated at 85 degrees so it stabilizes the heat. Another thing to remember when setting up any rack with cypress its gonna take about 48 to 72 hrs for the tubs to stabilize sincebthe cypress is dense and damp.