How to keep warm - a lesson from the Chukchi's

This guy sleeps in a Chukchi dwelling. He says it reached -60 at night. At the beginning of the clip he stands in what looks very similar to a Mongolian ger. Then there's a tent made of reindeer skins inside the ger. He says it's -30 outside and close to -30 inside. Inside the inner tent there is no blanket or sleeping bag, but only a candle and his body heat. How could he "stay warm as toast"? A dwelling inside a dwelling and body heat. In the previous minutes (in part 10) he was in another Chukchi ger with a fire where they were cooking. Even though he sleep well, they admitted it was a "difficult life" there reindeer herding.


So what can we learn? He slept comfortably through -60 in a tent inside a tent and nothing more except 2 candles and body heat. When he first entered, the ger was cold, about as cold as outside. The inner tent wasn't big, but it wasn't small. Air locks? Insulation and a little thermal mass and sunlight should go a long way in an earthship.