During the winter months, you might notice that pigeons, sparrows, or whatever birds populate your city stand stationary with their feathers puffed up. This peculiar move has a very practical purpose: it traps more air than when the birds' feathers are flat and, hence, also traps more heat. The same principle is at work in NuDown's line of jackets that allow users to better regulate how much warmth their outerwear offers—with air.
To create the system, the company collaborated with two designers, Julie Ringler and Kimi Davies Rice, who have fifteen years of combined experience at Patagonia. The jackets are each fitted with a pump that you inflate when you need to—instead of throwing on more bulky layers, just add air. NuDown says 20 pumps will add enough insulation to keep out the chill on chilly days, 30 pumps will give wearers more warmth on blustery days, and 40 or more is supposedly enough for the harshest conditions (the company gives the example of waiting on a windy ski lift). If the coat gets too toasty, deflate it to cool down.
Each pump supposedly adds one degree Fahrenheit of comfort, but for temps dipping below 20 degrees Fahrenheit, NuDown recommends using its Argon Gas Upgrade kit. The add-on will inject your coat with argon, the same gas that's used in double-pane windows and dry suits, since argon is better at insulating than air.
If the engineering details don't give you enough warm, fuzzy feelings, how about this: The company argues that the pneumatics in its coats reduce the amount of down that's normally needed to stuff them—a more ethical way to do business.
Men's and women's outerwear starts at $400 at nudown.com.