Yea, you need to make the room smaller. Another option would be to build a walk in enclosure out of 2x2 lumber and 1/4" plywood, you could line it with foam lining. Or you could use a small sauna and put a space heater in it, you can get them on Craig's List for practically free. The smaller the enclosure the less electricity it would take to heat it. My snake room in my basement is only 200 square feet, small enough to heat with a space heater but big enough for several racks of snakes and rodents. My snakes don't seem to mind the rodents being in the same room. None of my snakes are aggressive, well they used to be and I've tamed them all down LOL.