the room can be as low as 65 in the winter. It is a 65 watt RHP the guy I talked to seemed to be pretty knowledgeable about this stuff. he said with a thermostat it should be fine in a room 65 degrees or above with that size cage. The problem is animal plastics is mounting the RHP on the right side of the cage so if i put a divider in i feel like one side is going to be much hotter than the other. Also the guy from pro products said since its radient heat it should heat all the objects in the cage with no need for belly heat from heat tape or anything like that.