Igloos

Igloos can retain a temperature of 60°F on the inside during -50° weather. Ice is a bad conductor of heat. Any heat generated from inside the igloo, usually from body heat or a small fire, stays inside. A fire inside an ice structure? Won’t that melt the igloo? The warmth inside the igloo does melt the inner layer of snow and ice, but the air outside–often much colder than the air inside–freezes it back. The result is an additional sheet of ice on the interior walls, which adds to the insulation.