I hate to be a downer for sure. I just wanted you to be aware. Mine did great while I had the AC on holding temps steady. When I tried hatching with the AC off and the windows open (and the house temps fluctuating, but still comfy) I had miserable hatch rates. I think with the AC and heat on the house temps only fluctuate by a couple of degrees. The change without the AC and heat was maybe 5-6 degrees. It made a real difference.
Can you run some tests with your thermometer? I know mine shows lowest and highest temps. Can you place yours somewhere for 24 hours and see what happens to the temperatures? Using wood heat I would worry about it at night when the fire was banked.