How Do Igloos Keep People Warm?

Many people can’t imagine living​​ in the Arctic, where the lowest temperatures reach extremes of -65 °F. However, the Inuit, the Indigenous peoples of the Arctic and subarctic regions, have mastered the art of surviving in these circumstances by building igloos for shelter. But how can a cold material like snow provide warmth? Allow us to explain.

To learn the science behind igloos, you must first understand how heat moves. According to LabXchange, heat can be transferred through convection (the movement of gas or fluid), conduction (direct contact with something else), and radiation (electromagnetic waves). 

When body heat is dispersed in an igloo, it warms up the air that’s already inside it, demonstrating convection. Warmer air then rises and cooler air sinks. Igloos often have tiers for this reason: the entranceway is low-ceilinged and below ground level, the main living space is at ground level, and a sleeping platform is raised a foot or so above the living area floor. The coldest air collects in the sunken area nearest the entrance, while the warmest air rises to the level of the sleeping platform. Staying in the middle and top tiers allows people to keep warm despite their frigid surroundings.

That doesn’t explain why all igloos have a catenoid or dome shape. Igloos are built from dense snow blocks without any fastenings or interior supports, so stability is top of mind. The dome shape distributes weight and pressure evenly and strengthens the igloo. 

Additionally, igloos are built to capture lost body heat within their walls. Snow is made from up to 95 percent trapped air thanks to the tiny air pockets cushioned between its ice crystals. This constricted air provides excellent insulation against bone-chilling temperatures because it slows the transfer of heat to the outside world. 

With the proper building techniques, an igloo can be ​​40 to 60 degrees warmer than its surrounding environment, depending on the weather, the body heat of the people inside, and the thickness of the snow-brick walls.

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