I think often people think the only way to be warm is with artificial heat. But actually I prefer to sleep without heat – only my own body heat under the covers.

I never heat or insulate my truck cap – I’ve camped down to about ten degrees. Likewise when I winter tent – including during the coldest time of the year, Martin Luther King Day in the Adirondacks , I only use the heater before bed and when I awake in the morning, not while I’m sleeping.

The key is insulation and blocking drafts. Now they sell fancy below zero sleeping bags but they are unnecessary if you have enough layers. I use multiple, old sleeping bags. Many are ripped and old. I haul them back in the woods on a plastic sled in garbage bags. I wear long johns, wool socks and several layers of clothes to bed. They sell fancy winter tents and maybe they’re good for heavy snow expected to fall but unnecessary for ordinary a few inches of snow. Remember body heat will tend to melt a lot of snow from the roof of a tent. My winter tent is just an ordinary Kmart end of season special I got for $30 about a decade and a half old.

Staying warm in the woods is actually quite simple. Wear multiple insulating layers. Block drafts from your body. Stay dry or if you get wet quickly change into dry clothes. Wool stays drier then cotton. Use a heavy duty tarp for a ground cloth. Exposure to wind is much quicker to cool then exposure to cold – wind pull heat from the body. Focus most importantly on  insulating your toes and fingers first – they’ll get cold first. Hand lotion is essential – you’ll have cracked and bloody hands otherwise. Doesn’t have to be expensive girly stuff, just the big bottle from Wally World I’ve used for decades. 

You don’t need much if any heat to be warm except for your body, although I will be the first to admit being able to warm my hands and legs on the Big Buddy Heater first thing in the morning when I get up is nice – and makes winter camping all the more bearable.