What Do Different Down Jacket Down Fills Mean?

down jacket down fills

Gaining confidence that you can successfully beat the cold is part mental exercise and part gear. The mental aspects are individual and up to you, whereas the gear parts are dependent upon the clothing or equipment at hand. It can be hard to comprehend what the different down jacket down fills really mean when you’re looking at the various winter jackets on the market. Does down fill equate to heat? Puffiness? Density? This quick guide is should help you answer those questions and point you in the right direction.

Goose down jackets aren’t the only warm winter coats out there. Many synthetics exist, and we’re even starting to see space-age technology like aerogel make its way into men’s and women’s jackets (read our Oros interview for some insight there). But for most people looking for winter coats, a goose down jacket is likely the first place they’ll look. And boy, can that landscape look confusing.

Answering the question “what do different down jacket down fills mean?” isn’t totally simple, but the general gist is pretty basic. Essentially, a down jacket’s fill power is an indicator of its insulation per ounce. So, if you see a down parka or sleeping bag with a high fill power, it’s potentially just as warm as a down jacket with lower-quality down, but it will deliver that heat with less weight and a bit more puffiness. The higher the fill power, the lighter the jacket and the more compressible it is.

That compression attribute is often called loftiness. Goose down has a natural loft or “fluff” to it that’s largely responsible for the down’s ability to trap air. Where the air is trapped, it acts as an insulation barrier to retain heat. So, the more loft a down jacket has the more air it traps, which in turn means the more it can insulate you from those cold winter temperatures. (There’s a laboratory process used to evaluate fill ratings that you can read about here.) Although a down jacket with a lower down fill rating can technically keep you just as warm as a jacket with a higher down fill, that lower-fill jacket will require more material to achieve that, which can lead to excess weight.

If you’re out hiking in the cold or even camping, that weight makes a big difference. Down jackets or sleeping bags with a fill rating of 750 or higher offer great warmth with the least possible weight. Down jacket down fills between 600 and 700 offer very good warmth, down fills between 500 and 600 are good, and down jackets or sleeping bags with down fills of 400-500 are generally considered medium quality. Again, that’s not to say that they’re not warm, they just don’t offer the same insulation per ounce as higher down fill items.

For context, a sleeping bag with a 750 fill power is about 15 percent lighter than a 650-fill sleeping bag with the same temperature rating, and a sleeping bag with a 850 down fill power can be up to 42 percent lighter than one with a 550 fill power. If you’re car camping that might not be a big deal. If you’re backpacking into your campsite, that weight can take its toll on your back and legs. In my opinion, it’s always best not to feel like a total pack mule.

So if all things are equal, why doesn’t everyone just buy the highest possible down fill jacket? Because the cost of that down is not equal. Down fill ratings above 700 can be very expensive, because that higher-quality down comes from geese that have been allowed to reach their full age and are bred specifically for their down. Translation: it costs more to raise them, and the “turnaround time” for gathering that down is slower. Much like organic gardening, that can lead to extra costs.

As a result, most of the down jacket down fills you see in stores have fill ratings in the 400 to 550 range, because that down comes from geese that have been raised for food. The down those geese provide is simply a “bonus” to the meat they provide, and because they’re younger, the turnaround time between harvests is lower. Larger supply and shorter harvest cycles mean lower costs. According to outdoor company Denali, some costs can be attributed to the source of the down as well: “Duck down tends to be lower quality than goose down, with the exception of the down from the arctic eider duck, which is very high quality.”

Higher down fills generally mean more puffiness, but that puffiness can mean more insulation and therefore a warmer coat or sleeping bag. It also tends to mean a higher price. If you’re in the market for a down jacket, or are exploring what different down jacket down fills mean, a good rule of thumb is to buy the highest down fill you can afford. You’ll also want to balance that with how long you plan to own it. No need to spend a ton of money for a kick-around jacket, right? But if you’re at all like me and like to invest in things that will give you years of use, buy what you can afford, and you’ll be rewarded — and warmer — for it.

Jonas Allen

Jonas spent 17 years covering travel, technology and entertainment for regional and international media. He now writes about gear, clothes and tips to stay warm. He hopes his lessons will help other people who get cold (re)discover the great outdoors.

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