It doesn't really matter how big the generator is, it could be a 50K, but if it doesn't have some kind of filter to clean up the power (i.e. surges and inconsistent amperage), then it won't power a proportional T-stat. If you don't trust me, that's fine, just have pops start up the generator and try to run your thermostats. If they work, great. All I am saying is that after Hurricane Katrina, I was out of power for 31 days, and I tried to run my snake room with a generator and none of my Helix's worked. It would run a fan and the AC's though. I am not trying to get into a debate about electricity, as I am not that versed in it, but pass on some experience that I have had.