That depends on how cold the room that the cage is in will be. Flexwatt (like all UTH's) does not change the air temperature in the cage. All they do is heat the cage floor. If the room stays at least 65 and 68 or above most of the time Flexwatt will be all that you need. If the room gets and stays too much colder than that a radiant heat panel will be a much better choice.