I'm not sure if I'm the only one, but I have a PennPlax ThermaFlow PC (100 W) Heater. Whenever I unplug it, I have a re-adjust the temperature so that it just starts to maintain the temperature again. Even if I don't unplug the heater, it sometimes automatically adjust to a higher temperature without me knowing (raising the temp. all the way to 86F, which happened overnight) or even not turning on and resulting in a low temperature (to the point that it went all the way down to 64F, again, happening overnight). I have added a Elite 50W heater so that it wouldn't cause the temperature to swing at all (now it's constant at 79F)