I got the Monitor 30 vented kero heater going today in "The Silver Factory", after < 2 hours the thermostat turned off the burner:
Top temp is inside the TekFoil insulated 20x24 portion of the garage. Bottom temp is the other 20x30 portion of garage.
I was working on the bike in shirtsleeves - and snowmobile boots (the floor is cold on the feet).
This stuff works!
Mel Gibson, Andy Warhol, Dr Evil & Mini Me would all be comfy, too.