what about over loading a circuit. i know in my 2 car garage if i am running 2 heaters i pop the breaker. wood works great, thats how we heat my buddys dads body shop, start with soft woods to build the heat quick and then throw in some hardwood to maintain that temp. how much is a cord of wood? initial investment of the heater whichever you get, and what the yearly cost gonna run you to operate them. i would care more about the yearly than the cost of the unit.