Indeed - both heaters (torpedo and whatever the jeep had) blew hot air "around" and were not integrated into the vents. I think the jeep unit just drew from the gas can - not sure about the torpedo heater, but they were very economical for the amount of heat they produced.

-40 (air temperature - not windchill) is nothing to mess with. The instant heat from a battery pack is great if you're always close to charging, but there's absolutely no way I'd head into the wilderness in winter with just an EV.