I just pick up one of these a couple of days ago, works good for knocking the cold off. I have one of the parabolic dish that I let run most of the night and use the Heater Buddy to compensate in between. As with any thing with a open flame you need a little ventilation.The Heater Buddy states on the box safe for indoor use, instructions say to crack a window. If this helps my garage is 20x20 with 12' ceiling and I'm in a t shirt @ 28* outside