Here you go (this is a write up on another thread; I hope it's ok to post the link. If it's not, then delete it and forgive me mods): http://www.cornsnakes.com/forums/sho...light=rheostat

But yeah, a thermostat is wayyyyyy better. But if rheostat is all you can do, then it can work, just try to keep temps in your house as steady as possible.