For more than a week last winter, daytime temperatures hovered around 20° Fahrenheit. It wasn’t the first deep freeze we’ve lived through here in New England, but it was unusual for its length and record lows. Everything froze. Coast Guard icebreakers had to chug up the Connecticut River, but the ice grew so thick they made slow progress. It was a long time before the ships reached even the East Haddam Swing Bridge.
What shocked many people was the lack of rain or moisture. This was a dry cold, but that’s common in extreme temperatures. Consider the polar deserts; the central plateau in Antarctica sees maybe two inches a year because precipitation fails to form in the extreme cold. Cold and dry conditions anywhere make down jackets a necessity.
People always ask me: what’s the warmest jacket. As a rule of thumb, you achieve consistent warmth and comfort by combining baselayers, insulated midlayers, and shells, not from a single jacket. But I almost always recommend a down puffy for warmth and insulation.
explorers have ruled.
For its weight, down is typically the warmest and most compressible insulating material available to the apparel industry, so it appears in a wide selection of casual and technical jackets. Like all insulation, down creates dead space to trap heat as it leaves the body. These tiny plumules provide more efficient warmth than most other materials known to man. “Warmth,” is entirely subjective, but centuries of brave homesteaders, mountaineers, and arctic explorers have ruled. Down rules.
But not all down is created equal. It’s easy to get lost in the hazy jargon and technical calculations that describe down jackets and parkas, but they’re what really distinguish quality down insulation from the rest.
Consider fill power. Although a jacket’s warmth is entirely subjective, we can gain a rough estimate of its expected warmth from two qualitative measurements: the weight of the jacket and the down’s fill power. Fill power measures the down’s loft, its ability to fill space following controlled compression, in cubic inches per ounce. Heavier and higher fill power jackets will keep you warmer than lightweight, lower fill power jackets. Similarly, heavier jacket with a lower fill power will even out when compared to a lighter jacket with a higher fill power.
Unless you’re wearing it under a waterproof outer layer, down insulation isn’t always ideal in wet or humid environments. Unlike synthetics it loses loft (and heat) quickly if the face fabric soaks through, but the benefits of down well outweigh this risk. So when you’re buying a gift for someone perpetually cold, down’s definitely the way to go.