How Insulation Works

Choosing the right insulation can be confounding. No other building material comes in so many forms—from ground-up newspapers to foam boards to translucent gel. Understanding how insulation works can help us find the right material for a particular project.

The word insulation comes from the Latin insula—an island. Insulation attempts to create a climate-controlled enclosure by slowing heat flow—quite a trick, since thermal energy will always keep moving until equilibrium is reached, and your “island” of conditioned air is tiny compared with the outdoors. It gets even trickier when you consider that heat moves in three different ways: through conduction, convection, and radiation.