Harold,

I have only used the 120V heater so far. (our local has power, even at pit lane)
I tested it in the house at 70*F, I took the heater off at 220*F and it was still climbing. At the last race of the outdoor season it was 40*F and breezy. That day the best I got was 165*F. My experience is , once you are over a bout 140*F it has loosened up quite a bit. As stated, the saturation is the key factor.

Moto