I Tested Sleeping in a Car, Truck Bed & Tent at 10°F — A Clear Winner!

📖 I've camped for more than fifty years, and I put all of it in one book: https://ivansoutdoors.com Ask a hundred people at a trailhead where they would sleep on a ten degree night. A car, an open truck bed, or a small tent. Most of them pick the car without blinking. It has steel, glass and doors that lock. The car is the warmest looking shelter of the three, and it is also the one that kills people in their sleep almost every winter. So nobody gets me wrong, here is how I ran it. Same man, same sleeping bag, same pad, same cheap thermometer, three nights cold enough that the snot froze in my mustache on the walk from the fire. I had a ranking in my head for years from deer camp, ski trailheads and ice fishing weekends. Car first, truck bed second, tent dead last. That ranking did not survive the week. The engine stayed off in the car. Once it is off, that cabin is a metal and glass box sliding toward the outside air all night long. It keeps the wind off you. It does not keep you warm. Your sleeping bag does that. In December of 2008, three young women were found dead in their car in a parking lot near the Squaw Valley ski resort in California. They had been sleeping in it overnight. A storm came through, snow built up around the tailpipe, and carbon monoxide found its way into the cabin. The sheriff's office warned afterward that a pipe that is clear at bedtime can be drifted shut by two in the morning. What we go through: Why a car with the engine off drifts down toward the outside temperature The Squaw Valley case and the 1996 CDC report on snow-blocked tailpipes What idling really costs in fuel, and the states that restrict it The Mr. Heater Buddy, and the warning in capital letters inside its own manual Indoor-safe against sleep-safe, and why a battery CO alarm belongs in every shelter Frost on the windshield, ice down your neck, and why you crack a window for moisture The open truck bed, wind on top and a steel heat sink underneath Why a sealed and insulated truck cap is a different animal The small tent on packed snow, and the frost that falls on you by morning R-value, the ASTM F3340 standard, and why your bag rating assumes a pad of about R5 Stacking a thirty dollar closed-cell foam pad under your inflatable Comfort, limit and extreme ratings under ISO 23537, and which one is a survival number Keeping your breath out of your bag The final ranking, and the one decision with the key that changes everything Said plainly on safety: engine off while you sleep. Not mostly off. Off. No combustion heater running while you sleep, whatever the box says, because the manual says otherwise. A cracked window is for condensation, not carbon monoxide. Put a battery-powered CO alarm in there with you, and check where you are allowed to sleep in a vehicle before you park. The walls mostly decide two things, wind and safety. Warmth comes from what is under you. A thirty dollar piece of foam made more difference to how I slept than the thousands of dollars between the three shelters. If money is short this winter, do not start with a shelter upgrade. Start with the pad. Then a bag you have read the tag on. Then a little CO alarm. Then worry about where you sleep. Tell me in the comments where you spent your coldest night. Car, truck, tent, a hunting blind, the floor of a cabin with a dead stove. And tell me this: what did you learn the hard way? #WinterCamping #ColdWeatherCamping #CarCamping #TruckCamping #TentCamping #CarbonMonoxide #CampingSafety #SleepingPad #RValue #SleepingBag #MrHeaterBuddy #WinterSurvival #CampingTips #Overlanding #Outdoors