I put one in last Fall (a 40,000 BTU Mr. Heater Big Maxx) and it was a lifesaver over this past Winter. Mine is in a 2 1/2 car (440 sqft) detached garage. I live in the same area as you and this Winter was brutal, wasn't it? If you have Natural Gas available, make use of it. I had a 17,000 BTU Fahrenheat electric heater in the garage before and the cost per therm to operate is much cheaper with the Mr. Heater. On the other hand the advantage of electric was 1) no venting, 2) easy installation, and 3) 100% efficiency. It was also cheaper to buy but Boy it does make the electric meter spin! Good luck with your decision. I'm very happy with the decision to switch to NG. In ether case make sure you're well insulated before buying any heater.