Down is one of the lightest, most compressible, and most versatile insulations. It has been around for ages and has stood the test of time. There are many different types of down, but we stick to using high end hyper-allergenic down that will make your quilt one of the lightest around. Down is measure using a system called fill power (fp). Fill-Power (fp) is a way of measuring how much space a given down type can fill. For example, 850fp down will loft up to fill 850 cubic inches with 1 ounce of down, whereas 950fp can fill 950 cubic inches per ounce. Since insulation works by trapping microscopic air pockets, a higher fill power can trap more air pockets per ounce. For use in a quilt, this means that fewer ounces of down can be used to provide the same insulation by moving to a higher fill-power. A 20°F rating is always 20°F, but by moving to 850, 900, or 950, less down (by weight, not volume) is used to achieve that insulation rating. Enlightened Equipment uses Gray Duck Down (GDD) for our 850fp options, and Gray Goose Down (GGD) for our 900 and 950fp options.
All our down also uses the RDS certified, zero PFC DownTek water repellant treatment on all our downs. DownTek™ is a water-repellent coating that is added to goose or duck down. It helps the down resist moisture longer, and dry out more quickly if it does get wet. It is not fully water-proof, so normal precautions should be taken to keep your gear dry (such as a trash compactor bag for use as a pack liner, and/or the included waterproof stuff sack), but as an added layer of protection DownTek can give you more time to react to bad weather, pack or shelter failures, etc. You can read about one test of DownTek's water repellency here. All of our down is sourced from Europe. It is a side-product from the meat industry, and third-party audits verify that none of the down in the supply chain is acquired through live plucking, force-feeding, etc.
Loft is a big part of down and how it insulates. Loft is measured by measuring from the floor to the top of your quilt. The taller your quilt, the more down has been used and therefore the warmer your quilt is. We use the following loft measurements for our temperature ratings:
50° - 1"
40° - 1 1/2"
30° - 2"
20° - 2 1/2"
10° - 3"
0° - 3 1/2"
Synthetic insulation has some tradeoffs with down that may or may not make it more suitable for you. While it's less compressible and somewhat heavier when used for larger items like quilts, its excellent all-weather performance, faster drying, easier cleaning, and overall lower cost can make it a great choice for many issues, especially for warm-weather quilts. The synthetic material we use is called Climashield Apex synthetic insulation, which is one of the lightest and most versatile synthetic insulations on the market today.
In using Climashield Apex for quilts, we use the following weights of insulation per temperature rating:
50°F - 2.1 oz/sqyd
40°F - 4 oz/sqyd
30°F - 6 oz/sqyd
20°F - 8 oz/sqyd
Synthetic material weights may vary +/- 5% due to production variances.