well mine electric bill goes up about 100 bucks in the winter months, I running a space heater for the room to keep it as close as possible to the minuim temp levels ( about 82 degrees.) other wise of a night i bet the room would go to about 60 degrees. I also house 15 snakes in a single room with plans to possible get a 16 snake( been selling ratsto the local pet shop and he wants me ot purchase the tree boa from them ( the poor guy and the bps ) are in rought shape they can't get the snakes to eat but once every 3 weeks if lucky. these snakes should be weighting in about 900+ grams and I bet they only 500 grams if lucky.