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what is fill power?

Fill Power describes the volume of a down sample (usually 1 oz) subject to a certain pressure at a certain temperature (USUALLY 20° Celsius) & hygrometry (Typically at 65%). Measurements are taken Before & after pressure is applied to the sample 

  • while fill power refers to the quality of down clusters, weight can be added as a measure of warmth when fill power is constant between 2 products- in other words, if the fill power is the same to two comforters/duvets then the higher weight product will be warmer. 

  • loft of the product is influenced by fill power as well with higher fill power down resulting in fluffier and loftier duvets and pillows

  • feather quality is typically gauged by the length and curl in the feather where smaller whole (not crushed/chopped) feathers have softer feel and yet are resilient marking higher quality

think of it another way...

another way to think of fill power is like popped vs unpopped corn where an ounce of corn kernels will still be an ounce whether they are popped or not but the popped corn occupies significantly more space​

measuring and testing fill power

digital machines measure the ability of down and feather to recover loft under certain conditions with the process including: 

  • desired pressure and length of time is entered

  • a weighted disc applies pressure and is removed

  • sample of down or feather is added to canister (typically 1 oz)

  • fill power is calculated based on recovery of weighted lid (measurements are taken after various times and humidity)

testing is conducted both in Keeco facility labs and at IDFL where both use established standards set by law and idfb

keeco, llc is a member of the American Down and Feather Council 

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