None, as long as your hot side is the correct temp. Your ball will just not go to the cool side if it does not want to be cool. That's why a temp gradient is desired. They can move back and forth as needed. I have never used a ceramic heater, but I do use radiant heat panels. From what I understand, ceramic heaters do the same thing. They heat the ambient temp, as opposed to just heating a small spot on the bottom of the cage. Make sure that you use a thermostat though, because they can get very hot.