the chamber is actual heated by the MH's mostly. But at night I have one of those flat reptile pad heaters that is on a single stage Ranco controller. It turns it on when the tank get to 78 and turns off when it gets to 84. +/- a few degrees. during the day the lights heat it well enough to where I don't do anything. And depending on the ambient temp of my garage (where the chamber is) during the day the temps are like 90-95