My brother in Dickinson North Dakota asked me who lives in eastern Washington State about finding him a gas or Oil space heating unit for his 1200sq foot 10' high ceiling garage that he just built. He has R32 insutlation in the walls and ceiling.
Since we do not have -45deg.weather here, Im not sure what I can get him.
I suggest a direct vent wall heater (he might need 2 for a large space). Many gas, some kerosene, few #2 oil.
Check out Rianni, Monitor and Toyotomi(they have the only #2 oil direct vent wall unit I'm aware of)
Check out Hot Dawg heaters on the web. Nice little unit!