I had just got it and turned it on for the first time. I read when you first start one up, open up the door... do it outside...etc. The door will be closed from now on when I need to run it. I'm hoping if I can keep the temp about 50-60, to be comfortable to work. There is an automatic switch off when it reaches a desired temp... and will turn back on when it drops.I've never understood those - if it's cold enough for heat, it's too cold to have the door open, which means I couldn't use one of those.