What Is Down Fill Energy (2026): Fill Weight, Synthetics

Up to date February 2026: We have added a brand new part on caring for down and a few notes on Out of doors Very important’s Zero Sew material.

What Does Down Fill Energy Inform You?

The upper the fill energy, the larger the loft. Down puffer jackets and sleeping luggage preserve you heat by trapping the heat coming off your physique, retaining it in air pockets between the down. A better down fill energy means the down has extra loft, which implies there are extra air pockets, which implies that extra warmth is retained. If every little thing else is equal, that implies that the next fill energy garment shall be hotter than one with a decrease fill energy.

Sadly, every little thing else isn’t equal. Fill energy alone shouldn’t be sufficient info to know the way heat one thing shall be. There isn’t any direct correspondence between fill energy and the way heat a product will preserve you, as a result of there are various different elements to contemplate, like how a lot of that fill is within the product, how effectively it may possibly develop throughout the baffles or down chambers, how effectively does the material cease the wind, and so forth.

To know the way heat a down jacket, sleeping bag, or comforter shall be, it’s essential to know at the very least one different quantity: the fill weight.

What Is Down Fill Weight?

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Down fill weight is an easy quantity. It’s the quantity of down within the product, normally measured in ounces or grams. Utilizing down fill weight and down fill energy collectively may give you approach to evaluate two gadgets. For instance, the relative capacity of a puffer jacket to retain warmth may be estimated by multiplying the fill energy by the fill weight. Which means a 900 fill energy jacket with 2 ounces of fill weight will be capable to lure about the identical quantity of warmth as a 600 fill energy jacket with 3 ounces of fill weight. The large distinction between them, and the rationale they’re priced in another way, is the burden of every and the packed dimension.

In jackets, the burden distinction isn’t enormous. Because of this a few of our favourite puffer jackets are 600 fill energy. In the case of sleeping luggage, although, issues are completely different. Since there’s much more down in a sleeping bag, the burden distinction between equal quantities of fill energy is extra important. Except your finances is limitless, you’ll wish to take note of the warmth-to-weight ratio. How a lot heat do you want, and the way a lot weight do you thoughts carrying?

The one draw back to down fill weight is that some producers do not record this. It sounds nice to say your puffer jacket as 900 fill energy down, however when it’s a must to record that it solely has 2 ounces of it, it sounds much less spectacular. Much less respected corporations usually do not promote the fill weight. We record fill weight of all of the jackets we check.

Different Components to Contemplate

Courtesy of REI

Whereas down fill energy and down fill weight collectively give us a approach to evaluate gadgets, there are different issues to contemplate to get an thought of general heat. The third main issue is the baffles, the compartments which can be constructed into the product. When you simply sewed up a single piece of nylon as a shell and shoved some down inside, gravity and motion would push all of it down close to the hem in a matter of minutes. To keep away from this, garment makers add baffles to maintain the down in place. Baffle kind and form play an enormous half in how heat your jacket, sleeping bag, or comforter finally ends up being.