I thought that a heater putting out 17,000 BTUs would heat a two car garage in no time. Apparently, I was wrong. I set it on the highest temp and I couldn't even feel the blower standing 3 feet away from it. Still, I gave it some time just to see if it would heat up the garage since the temp. in my garage started out around 30 degrees. I let it run for around 6 hours and I expected it to be around 70 degrees but it may have gone up 10 degrees, maybe. If it has to run even 2 hours before getting warm, it's worthless to me. (I have a insulated/dry-walled garage). Not a good heater, at least for people up north.