Ive only used a CHE over a tank for quarantine & it was a bad experience. It was on a dimmer and I notice the fluctuation of room temp changed it drastically. I decided to run 2 UTH's on a herostat 2 instead. One side of the enclosure 80 and the other 90. The ambient temp doesn't really bother me when the entire floor of enclosure is heated.. If the room temp was very Cold then that would be another story.