I had a balmy 1 above this morning in southern Indiana. I checked the thermostat and the geothermal was still pumping away, no back up heat needed. They're calling for a big warmup after today. I had a beagle drop a litter of puppies on Monday, so I've had the woodstove blazing in the barn ever since. It was down to 32 in the barn this morning before I stoked it up. Even with the fire going I can only get it up to about 45-50 in there. 32x40x12 is a big space to heat up, and it's not well insulated at all. I've got a heat lamp on the puppies though, so they're staying warm enough.