That's great advice. About insurance and all. I haven't built an oil heater, yet, so I need to look into it. I am sure if I had a waste oil heater my insurance company would want to know. But maybe they don't need to know. Maybe! I live in Southern Illinois, close to Marion Illinois, or around 35 miles from Carbondale Il, where SIU is, southern IL University. I would be glad to get some waste oil , just to try out and see how it works. I would use wood, and that is an option, but I don't cut wood anymore, and wood takes an enormous amount to heat with, and wood isn't cheap. So that is why I am thinking of waste oil heat. Of course I am not in the garage all the time. What about a pellet stove. Would that provide enough heat. I have a 20 by 36 ft garage, and I know pellets don't put out the heat a wood stove would and rely mostly on radiant heat. Not a real big garage, but that is why I went a little small, because of economy.