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

Summary

The presenter tested sleeping at 10°F in a car, an open pickup bed, and a tent, using the same sleeping bag, pad, and thermometer. His main takeaway: the sleep system—especially the pad—matters more to warmth than the shelter itself.

Shelter ranking

1. Car — best overall, with strict safety precautions

   • With the engine off, the car’s cabin gradually cools toward the outdoor temperature. Its main advantages are blocking wind and keeping snow off you.
   • Breath moisture can frost the windows and dampen gear. Cracking the windows can reduce condensation, but an open window does not protect against carbon monoxide.
   • The presenter’s safety rules are to keep the engine off, never sleep with a combustion heater running, and keep a battery-powered carbon monoxide alarm inside.
   • The car is his preferred option only if these precautions are followed. Overnight vehicle-sleeping rules vary, so check local restrictions.

2. Tent — a respectable second

   • Choose a wind-sheltered site, pack down the snow, use a sturdy tent, and bring two sleeping pads.
   • A small tent can provide some wind protection, but frost may form inside and shake loose onto you. Venting helps limit moisture buildup.

3. Open truck bed — coldest and least comfortable

   • Wind can reach you over the bed rails, while the metal floor draws heat away from your body.
   • A sealed camper shell, closed drafts, and insulation beneath you can make a truck a much better winter shelter. The test’s low ranking applies to an open bed.

Cold-weather sleep tips

• Prioritize insulation beneath you. The presenter found that cold came up through his hips, shoulders, and back.
• Check a sleeping pad’s R-value, which indicates its resistance to heat loss into the surface below. For winter conditions, he cites a target of roughly R-5 to R-6.
• Pad R-values can be combined approximately. For example, an R-2 pad plus an R-3 pad gives about R-5. A closed-cell foam pad under an inflatable adds warmth and provides backup if the inflatable leaks.
• Read sleeping-bag temperature labels carefully:
  • Comfort is the more comfortable-use rating.
  • Limit is colder and assumes a more curled-up sleeping position.
  • Extreme is an emergency or survival rating, not a comfortable sleeping temperature.
• Keep your face out of the sleeping bag rather than breathing into it, which adds moisture to the insulation. Wear a warm hat and use the hood instead.

Heating and carbon monoxide cautions

• The presenter warns against idling a vehicle to stay warm: a blocked tailpipe can allow carbon monoxide into the cabin, and idling also consumes fuel and may violate local rules.
• He describes past carbon monoxide incidents involving snow-blocked exhaust pipes, including a fatal case near a California ski resort and poisonings reported after a 1996 winter storm in Philadelphia and New York City.
• He says the Mr. Heater Buddy manual warns against operating the heater while sleeping. He recommends using such a heater only while awake and attentive, with ventilation and according to its manual, then turning it off before sleeping.

Notable locations, products, and references

The presenter is from the Ivan The Veteran channel. Locations mentioned include Squaw Valley, California, Philadelphia, and New York City. Products and references include the Mr. Heater Buddy, closed-cell foam sleeping pads, REI winter-camping guidance, ASTM F3340 pad testing, and ISO 23537 sleeping-bag ratings.