I have a 150,000 BTU torpedo heater that will have you working comfortably in your T shirt in just a few minutes. I have a thermostat inline on the power cord to make it versatile. I err on the side of caution, to avoid drawing in any combustible fumes I prop the overhead door open about 24" and put it just outside, blowing hot air in. The downside is that it will burn the entire 10 gallon tank in a day, and the price of kerosene is ridiculous. The manufacturer plainly states not to burn diesel fuel in it.