I have a King ceiling hung heater. I think it is 7500W. Gas will for sure be cheaper to operate over the long term, but depending on where gas line is, initial install costs could be pretty high with a gas unit. You also have to run a vent (chimney) exhaust out the roof for a gas unit. So you have that expense as well with gas. My electric bill goes up about $75 - $125 per month in the winter months when the electric heater is active. Dont forget my garage is insulated almost as well as the rest of the house (walls and ceiling). I would not waste my time trying to heat an uninsulated garage.Steve - what electric heater do you have in your garage? Now that I have a 3 car garage I'd like to be able to work on my car during the winter months. I'm torn between getting an electric or gas based on the cost of operation.