Actually something that small you could heat with a Coleman lantern. Get it warmed up, turn it off, vent it out (Insulated walls, floor & ceiling retain heat), get in your bag and you'll be fine until morning.

Hey NSAQAM, Larry is very "IN", LOL
You also dishonor the 28th division by using the unit patch as an insult.
As for the liar, welcher Bricktop, his day is fast approaching.
Coward trolls won't accept PMs.
How's the phantom "campfire" coming ?