How do igloos stay warm?

An igloo can be warmer than the air outside because snow contains trapped air that slows heat transfer. The walls also provide shelter from wind. Heat from the occupants warms an enclosed space instead of being carried away as quickly.

Why use snow instead of solid ice?

Snow is a structure of ice crystals with air between them. Those air spaces are important to its insulating behavior. A snow-block house is therefore different from a house made of solid, transparent ice.

The useful material must also hold together. Choosing suitable snow is part of the skill of building, not an interchangeable step that any loose powder can satisfy.

Where does the warmth come from?

Insulation reduces heat loss; it does not generate heat. People provide heat inside a shelter. How warm the interior becomes depends on the weather, snow, shelter size, ventilation and heat sources. There is no single temperature that describes every igloo.

What does the shape do?

A curved enclosure provides an enclosed living space without a timber roof frame. The shelter’s design, entry and interior arrangement work together with the material. Understanding the whole structure is more useful than treating snow as a miracle substance.

A shelter built from knowledge

Snow houses are associated with Inuit building traditions, but they should not stand in for every Inuit home or community. Homes also used materials such as sod, stone and whalebone. Local conditions and seasonal needs shaped different solutions.

The engineering story is about people reading a landscape: recognizing useful materials, judging conditions and applying knowledge passed between generations.

Explore the sources

• Government of the Northwest Territories: Hunter Education Student Manual — snow insulation and traditional shelters.
• The Shelter Characteristics of Traditional-styled Inuit Snow Houses — a research paper in Arctic.
• Library and Archives Canada: Inuit dwellings — materials and seasonal housing.

This is an explanation of history and physics, not a guide to constructing or occupying a snow shelter.