garage heating

there is nothing wrong with the proper propane heater at all . If you get the type that bolt up to your roof and vent outside through b-vent and use a heat exchanger. Same as a natural gas heater,,just uses propane (different orfice size). Reznor makes a perfect little 0 clearence 50,000 btu heater that would be perfect for ya,,,,about 550.00 canadain not installed