Choosing a Down Jacket

For outdoor adventurers braving winter weather, a down jacket is the ultimate layer of warmth.down jacket It's a versatile piece that can be worn as an ultralight insulation layer while backpacking or climbing, or as a windproof outer shell for a snowy day on the slopes. Down jackets offer remarkable warmth for their weight and compress down into a very small space in your pack, making them ideal for multi-day adventures or big trips. However, when it comes to choosing a down jacket, there are many factors to consider beyond just the warmth-to-weight ratio, such as fill power, fill weight, and shell fabric thickness (also known as denier).

A down jacket's warmth comes from the tiny feather clusters that make up the insulation.down jacket These clusters create millions of air pockets that trap warm body heat to keep you toasty. As the down clusters get warmer, they clump together more tightly and generate even more warmth. This is why down is able to generate more warmth than any synthetic insulator.

The quality of the down is also a factor in the warmth-to-weight ratio. This is measured by a rating called fill power, which indicates how much space one ounce of down occupies in a climate controlled test cylinder. The higher the fill power, the more lofty and better quality the down. This allows the jacket to be lighter because it requires less down to achieve the same level of warmth.

When choosing a down jacket, be sure to check the fill power and fill weight, as these are the most important factors in determining warmth-to-weight. A higher fill power number means that the down is more lofty and of a better quality, while a lower fill weight number simply means the jacket is lighter.

Another thing to consider is the waterproofing of your jacket. All down is technically waterproof, but most manufacturers treat their down with a durable water repellent (DWR) that makes it resist soaking in moisture for a longer period of time than untreated down. However, if your jacket is saturated by a prolonged downpour or wet snow, it will lose its loft and be very cold until it dries out.

Serious alpinists will want to consider the shell and lining fabrics of a down jacket as well. The more delicate, paper-thin shells used in ultralight jackets are more fragile than their thicker counterparts, but they can be extremely lightweight and super warm. Montbell, for example, offers a number of impressively light down jackets like the Plasma 1000, which features ultra-premium 1,000-fill power down and a paper-thin 7D shell. The more substantial 10D and 20D shells that are used in midweight and heavy-duty down jackets are considerably more durable but also add to the overall weight.