Forget Down—Aerogel Is the Insulator of the Future

A Depression-era insulating material is becoming the hottest thing in outerwear

aerogel warmth cold weather gear cold weather apparel down jackets insulation winter insulation cold jackets insulation silica

A hockey puck-size sample of aerogel.     Photo: Inga Hendrickson

6:1

Ratio of down to aerogel needed to retain the same amount of warmth

You’re looking at the lightest and warmest material on the planet. Officially, it’s called silica aerogel, but it’s so lightweight it’s referred to as frozen smoke. The substance was developed in a lab 80 years ago, and that’s pretty much where it stayed until 2007, when NASA figured out how to use it to keep instruments warm on the Mars rover. Industrial manufacturers and gear geeks have been toying with it ever since. In 2010, apparel maker Champion put aerogel inside a jacket lining and sent mountaineer Jamie Clarke up Everest; he overheated. But designers kept tinkering, and this summer the material makes its debut in running shoes, sleeping pads, snow pants, and, yes, space suits.

WHAT IT IS: Aerogel is 90 percent air and 10 percent silica. The silica is extremely porous, but because the holes are 1/10,000th the diameter of a human hair, they block nearly all airflow, making it supremely effective as an insulator. It’s also shockingly light: the hockey-puck-size samples shown here—enough to outfit a pair of mountaineering boots—weigh just nine-tenths of an ounce each.

HOW IT’S MADE: Silica gel is poured onto mats of polyester, which are rolled up in tubes, placed inside 12-inch-thick steel chambers, and exposed to immense pressure, turning any liquid to gas and producing a very low-density solid that can be cut into almost any shape. The only problem: what’s left is incredibly brittle. Bend it and it turns to dust.

THE BREAKTHROUGH: Last March, German aerogel maker Cabot released thin sheets of silica packaged in polyester pouches. When the silica crumbles, the threads’ fibers hold it in place, retaining its structure.

WHAT’S NEXT: Aerogel essentially nullifies heat transfer, so it’s being used as insulation for windows, thermoses, even paint. But it’s also breathable, so gearmakers are experimenting with it as a lightweight alternative to down. Of course, it’s still outrageously expensive (five times the price of synthetics like Thinsulate), but that will change as production increases, giving cold-weather aficionados—and geese—something to cheer about.

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