Nothing keeps you warmer than goose down. Well, until that down gets wet and flattens like hair in a storm. The North Face—spurred on by extreme mountain-climbing athletes begging for lighter-weight warmth—did the goose one better, creating ThermoBall, a new synthetic insulation in miniscule—think .15-inch diameter—balls that cluster and loft akin to down, but with water-repellent properties. The result: The North Face’s lightest (11 ounces), most compressible cold-weather coat, which lets you worry about water no more.
Joe Vernachio, The North Face VP, says the California-based company developed an entirely new manufacturing process to get those tiny polyester balls to layer evenly, giving the comfort and flexibility of down in the best warmth-to-weight ratio of any synthetic coat—and nearly on a par with actual down.
A simple test of the ThermoBall in mid-20-degree temperatures with a wind chill howling to single digits can leave you skeptical of the lightweight nature of the coat. But the performance impresses, moving this technology safely away from the gimmick label.
ThermoBall matches the properties of 600-fill down by clustering together within the material and creating dead air. As heat leaves the body in what are essentially minivortexes, ThermoBall disrupts those vortexes, creating “chaos inside the jacket so there is no line of sight through to the other side,” in the impressively dramatic words of Vernachio. That action bounces the heat back inside.
Surprisingly, despite all that chaos, ThemoBall settles, er, down and compresses easily and peacefully into its own zippered pocket.
Tim Newcomb covers stadiums, design and gear for Sports Illustrated. Follow him on Twitter at @tdnewcomb.