Wow, I guess I'm lucky. I've been monitoring the daily usage on my AL power app and my bill hadn't gone up much at all. I am in AL though. But we've had quiet a few nights in the low 50s with upper 40s coming next week.(can't wait). But my settings are very conservative. I've been primarily using economy mode.(In aug it would actually rise a few degrees with no heater running) And my thermostat is set to 99. I've been running it 100 the last few weeks though. Also I'm only running 4 one hour filter cycles per day. Even at nights when it dips down into the 50s, I leave the heater off. I check it the next morning and my hot tub is still where I left it.