I have a ~750 square feet garage, insulated walls and ceilings, part concrete / part dirt floor, with two garage doors. A Modine HotDawg or similar gas heater would be ideal, but I'm getting quotes of $3200 and up for an install. Wondering if anyone has used an electric heater, like any of these units? Dr. Heater 10000w Dr. Heater 7500w Farenheat 7500w I live in MA, so winters get cold, and the shoulder seasons can be chilly, too. I wouldn't be using this to keep my shop at a certain temp, except when I know I'll be out there and working. Thoughts?