I turned ours on mid-October. My husband would leave it off forever if I let him. The outside overnight temps were around zero and our inside temps were mid-50’s when I put my foot down and turned it on. That storm passed and we have warmed up a bit, so we’ve had stretches where it was turned off, but when the house temp gets to the low 60’s I’m turning it on. I love to bundle up, but there are limits!