I almost said "it goes without saying" but really nothing on this forum "goes without saying" since there are so many people reading/learning about an issue/subject/question, not just the one person who posted it.
From my experiences camping, it's a good idea to bring along warm winter socks to sleep in. Paired with a proper cold weather sleeping bag and a hat with ear flaps, they can make sleeping very comfy even when the weather gets really chilly. Even if you don't need the hat/socks very often, they don't take up that much space, and they are the difference between surviving comfortably and misery. Frozen ears and toes aren't something anyone wants to go through. I've woken up to iced over cups in my cupholders before and been quite comfortable all night, despite the cold.
This won't replace a heater of some kind, but it takes the stress out of going to sleep when it's snowing outside, knowing you'll be fine no matter how cold it gets.
Another possible option I'd say would probably not work for everyone, but I'll mention it just the same in case it helps someone. I used to have an auto start on my car. My ex and I originally had it installed in Vegas, and they installed it incorrectly so instead of starting the car and the heater/AC it would start the car and the radio. The idea is that you can get your car cooled down or heated up before you get into it. By the time my now-ex and I noticed it was incorrectly installed, we were back in ID, so we just lived with it.
The cool thing about it was that I read the instructions manual that came with the remote starter and figured out how to program it to start every 3 hours. This came in really handy once I had moved back to MN. In the dead of winter I didn't have to wake up in the middle of the night to go start the car, let it run for a while, then shut it off again. When it's too cold you really have to do that to warm up the engine if you don't have a block heater otherwise you just won't be able to start your car in the morning.
Where this comes in here is I could program the remote starter to start every 2, 3, 4, or 5 hours, and stay on for a chosen duration. If it was wired properly it would have warmed up the vehicle every 2, 3, 4, or 5 hours. I personally wouldn't sleep with my vehicle running (any duration) unless I had a carbon monoxide detector. Even if it only started it once in the middle of the night it might take the edge off in places where the temp is hovering close to -35°.
~angie
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