I agree with Dave. 70 degrees ain't that cold for a rhac. It regularly dips down into the 40's & 50's at night in N.C. If I was to go down and check the temps in my rhac cages right now they'd probably all be in the upper 60's. I don't provide any kind of supplimental heat at night. Never have, never will. Heck, my rhacs are lucky if it gets up to 75 in the DAY during this time of the year!