Until recently, 1,000-fill down has been a rare commodity. Jackets that included it were听always few and far between. But this year, there will be more of it than normal, giving weight weenies new options for ultra-packable warmth. Don鈥檛 get too excited, though: quantities will be limited, and prices will be steep听relative to what we鈥檙e used to.听Mountain Hardwear, for example, initially only made听2,000 of its flagship听 ($375), whereas听you can likely snag its听bestselling , and for $50 less. Is听the extra fill power, and two-ounce weight savings, really worth the hunt?
Down Math
Calculating fill power is a helpful way to judge the weight-to-warmth factor of different down jackets. Fill power is a measurement of the quality of the down, and it鈥檚听the approximate听volume in cubic inches of one ounce of down.听So one ounce of 650-fill down takes up approximately 650 cubic inches of space, one ounce of 850-fill down works out to 850 cubic inches, etc. It鈥檚 important to note that fill power does not necessarily equate to warmth. Here鈥檚 what the numbers mean: Because 1,000-fill听down is high in volume, it鈥檚听not as听dense as other fills听and has more room to trap air within the plumage. A jacket with听650-fill down takes up less volume than one with 1,000-fill down,听so it鈥檚 denser and has less space for warm air. But when it comes to warmth, what really matters is听how much听of that down is stuffed into the jacket.
We鈥檒l use Mountain Hardwear鈥檚 Ghost Whisperer UL as an example. This听jacket features two ounces of 1,000-fill down (this important measurement is听frequently noted听alongside the overall weight of many jackets on the product page,听though not every brand lists it), which means the volume of the down is roughly 2,000 cubic inches. Keep in mind that warmth is tied to volume. So a jacket with 2,000 cubic inches of 800-fill down should be just about as warm as an otherwise identical jacket filled with 2,000 cubic inches of 1,000-fill down, like the Ghost Whisperer UL鈥攖he 1,000-fill version will just be lighter.
But how much lighter? Using a little high school algebra, we can work backwards, dividing听the Ghost UL鈥檚 2,000听cubic inches of down by 1,000 fill to determine that the down weighs two ounces. How does that compare to an 800-fill jacket? The same 2,000 cubic inches (meaning the jacket is exactly as warm)听divided by 800 fill yields 2.5 ounces. Even a 650-fill jacket of the same warmth weighs only three ounces. In smaller jackets, the weight difference from 1,000 fill to 850 might be minimal, though the difference could be larger in products like sleeping bags, which use tens of thousands of cubic inches of down.
So听while fill power definitely shaves ounces for those looking to slim down their kit, the weight听difference in many jackets is minor, and real听weight savings are听likely to come down to everything around the down. If manufacturers spend听big bucks filling their jackets with 1,000-fill down, it鈥檚 likely because they鈥檙e trying to make them superlight. That means they鈥檒l also try to keep the weight of the fabrics, zippers, and other features to a minimum. But if weight is less of a concern, they might boost durability and function and use cheaper down.
How I听Tested
I took these jackets听backpacking, ice climbing, and backcountry skiing across the West between the fall of 2019 and the summer of 2020.听Temperatures ranged from the low fifties听to bitter single digits below zero. Given the variety of jackets听and their differing warmths, each generally听fell into its own optimal activity听and temperature ranges. (The latter is a听subjective assessment based on my body, what I was听wearing with the jackets, and the activity of the day.)
Mountain Hardwear Ghost Whisperer UL ($375)
Best For: Nerds obsessed with ultralight tech
Weight: 6.7 ounces (men鈥檚 medium)
Down Weight:听2听ounces
Optimal Temperature Range:听50 to 35 degrees Fahrenheit
There may never have been a more fully featured down jacket at this weight鈥攐r听at least听I鈥檝e yet to see it. Largely thanks to the featherweight nylon face fabric (or outer layer)听that lends its name to the jacket, the Ghost Whisperer line has been able to claim that title for a while. But the brand鈥檚 newest iteration swaps out 800-fill down for the primo听1,000 fill and replaces ultralight ten-denier face fabrics with听a downright paper-light听five-denier version, bringing the 鈥檚 weight to that of a billiard ball.听
That听lightweight warmth was enough to take the chill off shoulder-season summits or while making breakfast on summer backpacking trips in Montana鈥檚 Beartooth Mountains, when听temperatures were in the low fifties. It makes for a toasty midlayer (it fits great under a ski shell) during the colder months, but it鈥檚 probably not going to be my only puffy on chilly ski tours (adding a parka would be nice for frigid transitions). And at this level of warmth, the difference between the UL and the 8.8-ounce 800-fill version is really only going to be noticed by picky ounce counters. Cost aside, the weight savings may or may not be worth the paranoia that comes from brushing this jacket against a branch. I babied mine and still saw a few small snags while bushwhacking.
听
Eddie Bauer Centennial Collection MicroTherm 1000 ($399)
Best For: Moving while bundled up
Weight: 9.6 ounces听(men鈥檚 medium)
Down Weight: 3.2 ounces
Optimal Temperature Range:听50 to 30听degrees Fahrenheit
The听 only features just over an ounce of additional down compared to听the Ghost UL, but Eddie Bauer听took few chances on the face fabric with a sturdy (for this category) 20-denier material. Plus, stretchy fleece panels under the arms boost flexibility and breathability.
This jacket听kept me slightly warmer than the Ghost Whisperer. I stayed听comfortable into temperatures in the high forties听without moving. The underarm panels didn鈥檛 seem to compromise warmth听but were a welcome feature while moving above the tree line during fall hikes up Bear Peak in Boulder, Colorado,听with early-morning temperatures in the high forties. The face fabric still deserves some caution around sharp objects, but I felt confident jamming it into my backpack or wearing it while walking over and around听blowdown.
Mont Bell Plasma 1000听($439)
Best For: Shoulder-season backpacking
Weight: 8.4 ounces (men鈥檚 medium)
Down Weight: 3.4 ounces
Optimal Temperature Range:听45 to 25听degrees Fahrenheit
While the down weight听of the Mont Bell is similar to that of the Eddie Bauer, the baffle design of the听 stacks the down a little thicker, making it noticeably puffier and warmer than the Mountain Hardwear听or Eddie Bauer听jackets. It was my go-to puffy for winter backpacking trips in the desert: I听took it down Little Death Hollow to the Escalante River in Utah, where morning temperatures听didn鈥檛 creep beyond the high thirties. It was also a comfortable jacket for ski transitions on days when the mercury dipped to the low thirties. The seven-denier face fabric feels a little crinkly听and lightweight and was just as delicate as the Ghost Whisperer鈥檚鈥擨 grazed the cuff over a coarse boulder while hiking along the Escalante and introduced a small tear鈥攂ut the warmth-to-weight ratio of the Plasma is nearly the best of the jackets I听tested. The whole thing packs down to slightly smaller than a 32-ounce Nalgene.
Rab Zero G ($550)
Best For: Super-cold adventures
Weight: 10 ounces (men鈥檚 medium)
Down Weight: 4.05 ounces
Optimal Temperature Range:听35 to 15 degrees Fahrenheit
Bigger puffies like Rab鈥檚 are where the value of 1,000-fill down becomes more apparent. With additional听down on the inside (it uses more than twice the down of the Ghost Whisperer), the weight difference between a similarly warm 800-fill jacket could be a lot more obvious. The Zero G was warm enough as an ice-climbing belay jacket or a puffy for full-on winter backpacking up Montana鈥檚 Hyalite Canyon. The trade-off, though, is that additional听1,000 fill makes this the most expensive jacket I听tested鈥攂y more than $110.
The Zero G quickly became my preferred winter puffy on days when the digits听dropped well below freezing.听Thanks to a ten-denier face fabric, it stayed surprisingly intact (I put one small nick in the body with an errant ice screw in my backpack), even though it saw more use than any of its competitors.