Ok, I've been reading the heater talk...here's one that really puts out the
heat.

I have a US army surplus multifuel heater that is about a 12" cube, runs on
24 volts, has a wall mount thermostat, and runs on gas, diesel, kerosene etc.

I mounted one in my tugboat, but it could work outside with a piece of dryer
duct for fast portable heat for campers....15,000 btu! (could also mount
inside for mobile heat, but it is kind of noisy!)

Ed