I think I would want to heat it the room slowly before I started it up, then check the exhaust was maintaining the correct working temperature in the space.
Thats the plan. I have a concern though. Original plan was to use my propane heater. Usually more effective than electric space heaters for example. I dont see why but would the propane fumes cause harm to the machine? My other option is the space heaters. I HIGHLY doubt they will even put a dent in the temperature though. Keep in mind the heater is only for INITIAL startup. A heater will NOT be on upon machine boot.
I'd be nervous about running it on fumes, though in truth it would probably be ok.
Can't you just put it in a cooler with warm air to start up, and use the exhaust to warm the space? Or even redirect part into the the cooler?