I have about 500 Sq Ft of space to heat. 15' X 35'. Was thinking of a garage heater (5000 Watt 240V). Basicly a room with windows and a door on one wall. The other 3 walls are shared walls. Can't make any holes to vent thru ceiling. Do I have any other options or electric the only way to go?
Also, no AC or Heating unit of any kind is installed.