Ever wondered what that fluffy stuff is that keeps you warm at night? Are you down to learn? Down has been keeping campers, hikers, and outdoor enthusiasts warm for longer than we can remember. It’s many hiker’s insulation of choice because of its unmatched warmth-to-weight ratio and ability to compress into a small footprint.
Fill Power (FP)
There are a few important things to understand about down, which will help you better enjoy your time in the great outdoors. The first thing that comes to mind is Fill Power (FP). Fill power is a term used to describe the quality of down.
It is universally understood that the higher the FP number, the better the quality. While this basic reasoning is true, there are a few things to keep in mind. The technical meaning of “fill power” is how many cubic inches one ounce of down takes up. This is tested by filling a large cylinder with one ounce of down, then adding a weighted plate on top of the down for one minute. The volume is then measured to determine the fill power rating.
Can you guess how many cubic inches 850 FP down takes up? If you guessed 850 cubic inches you are right!
The higher the fill power, the more volume the down takes up. This means that one ounce of 900 FP down will create more loft than 850 FP. A good point of reference is to check out some of the quilt manufacturers’ specs. You will notice that as the FP rating increases, it requires less down fill to achieve the same temperature rating. For example, a regular 20 degree quilt has the below specs.
850 FP - 19.35 oz of down fill
900 FP - 18.60 oz of down fill
While they are providing the same warmth, the one made with 900 FP weighs less because it requires less down to achieve the same temperature rating.This variation in fill power ratings allows quilt manufacturers to push the limits in creating uber light quilts that are also uber warm — ultralighters rejoice!
If you are in the market for a quilt, sleeping bag or jacket, we recommend that you do not get anything lower than 850 FP. We believe that anything less than 850 FP is not going to offer you the consistent fluffy warmth that you rely on in the backcountry. Once you go below 850 FP you start to see more quills and broken feathers in the down fill. These are not conducive to keeping you warm.
850 FP is a great option for those who are looking to get the most “bang for your buck”. It is tried and true, affordable, great quality, and performs very well.
900 FP is the next step up in quality. Although it is more expensive, it is worth the investment if you are looking to lower your pack weight without sacrificing warmth at night. 900 FP has a more premium feel, it lofts very nicely and creates beautifully plump, warm quilts and sleeping bags.
1000 FP is the down you want if you are a hardcore ultralighter. The person who wants a quilt with 1000 FP down definitely has the mindset of, “money is no object, I just need to lower my base weight!” (Yes, we are guilty of this too!)
The difference in quality is astonishing when comparing 1000 FP to any other fill power. There is truly nothing that compares to 1000 FP down … just know it's freaking amazing.
Pictured below is a 1000FP quilt from Trailheadz Hammocks. To our knowledge these are the only 1000FP quilts on the market, and they are incredible!
Please note that the FP rating does not determine how warm the quilt will be. The warmth is determined by how much loft the product has and how much down is in the product. These two go hand in hand.
More Down = More Loft
More Loft = More Warmth.
This is why a 10 degree quilt is far heavier than a 40 degree quilt. The 10 degree quilt requires more down (about 9 or 10 oz more) creating more loft to trap more warmth around the user.
Treated vs Untreated Down
Down can also be treated. Meaning, it is coated with a hydrophobic treatment, which increases its natural water-repellent characteristics. In our opinion, there is no reason to use untreated down in outdoor gear. Choosing a treated down gives the user a “one up” on the environment — it plans for the unexpected, even if you don't.
Treatment allows water to repel off of down more efficiently and it will also dry out quicker than untreated down. Choosing a quilt with treated down is an especially good idea for AT thru-hikers because they will endure a ton of rainy days and be forced to set up camp in humid conditions very often.
Color — Grey vs White Down
Down is naturally grey and white. Grey is the more common and more affordable choice, while white is a little more expensive and harder to come by. These colors are not an indicator of the down quality.
Manufacturers will typically choose a white down if, and only if, the shell of the material (quilt fabric) is a light/ transparent color. If the quilt is yellow, white, or a light blue, for example, you will be able to see the down clusters in the sunlight. This is when it is preferred to use white down as opposed to grey.
Goose vs Duck Down
Another common question is whether there is a difference between goose and duck down. There is no difference in the performance of the product, as long as the fill power ratings are the same. However, the higher fill powers are only attainable with goose down since the clusters are larger. The larger clusters also make the product more robust, and will commonly outperform their stated fill power rating range. For example, a 900 FP rating with goose down may be closer to 925 FP, while the duck down may struggle to reach the 900 FP rating.
Thank you for getting down with us. As always, let us know if you have any questions, we love to help!
Hi, we’re Nick DeWald and Nathan Schutte. As DIY / MYOG enthusiasts, we noticed the biggest downfall of making your own gear can often be the daunting costs of materials. This is exactly why we started Loose Goose. To empower DIY enthusiasts to explore their full potential by offering high-quality down at an affordable price. Learn more and check us out >>> https://www.loosegoosedownsupply.com/
4 comments
Vick R Hines
Down inflation
Long time makers of backpacking gear will have noticed that the claimed volume of down available today is much greater than the best down available previously. There are legitimate technical reasons why down today has higher volume. One is that the method for separating the plumes of down from the fluffy feathers that still have quills has improved, but the second is that the method for measuring the volume of down has changed. Sometime in the late 1980s or early 1990s the manufacturers ganged up on the feds to get the method of measuring down volume changed. Previously it had been measured using a clear graduated cylinder with 1 ounce disc that just fit the inside of the cylinder. One ounce of down would be placed in the cylinder and the weight was pressed down until the down was compressed. The official volume of the down was the recovery volume, the volume one ounce of down could reach while pushing a one ounce weight. The outfitting industry was using the volume of down and their products as a measure of quality and as usual they wanted to improve the sound of their products. So claiming that your sleeping bag had 800 cubic inch down was better than 750. And 900 in.³ was a whole lot better than anything else out there. The industry got the test changed. Instead of measuring the recovery volume, the new test measured the compressive volume, the volume that remained after the weight had been placed on the uncompressed down for one minute. The quality of down available in the United States suddenly jumped by about 150 in.³ per ounce. What this means for the maker is that if you calculate your down requirement based on having 900 in.³ down your quilt will not fill out. The volumetric capacity of the lower weight of down will not be sufficient to lift the weight of the shell. Theoretically that amount of down, if left alone, could fill 900 in.³ but if you press it and then release it, it will fill only 750 or 800 in.³ In other words the maker would do well to take something off the manufacturers’ claim. Generally, I take 150 off any down claimed to be 900 in.³ In the case of Ripstop by the Role I take off only 100 because I think that’s more accurate. They only claim 850 cubic inches. I don’t think anyone is providing down that has higher fill than 800 according to the old standard.
TJ
Not a word about how geese and ducks are treated when removing their down. Typical.
Jason
Nice article. One point of contention is the industry moving toward treated down. Last time I checked, down (duck or goose) is naturally hydrophobic therefore it begs the question why bother unless this is another attempt, similar to ethical down, to charge more money. In fact, Western Mountaineering does not apply DWR to their bags based on the aforementioned fact.
Eric B.
I agree that DWR treated down is better – even IF the DWR will wear off after 8 or so washings. How many of us own down garments we’ve washed 8 times? Right, damn few. TheJapanese TORAY company has a down DWR treatment that has been “shake tested” to be the best DWR so far. (Down & Feather Institute test).
As for jackets and parkas that will not often be packed in a stuff sack and carried in a pack I think 850nor 800 fill is fine because it is LESS compressible by such things as packs and body movement and will thus keep its loft better than pricey 900 and 1,000 fill down.