What Is Down Fill Power (2026): Fill Weight, Synthetics
WIRED explains how [[down]] fill power measures the loft of an ounce of insulating [[down]]—the lab test reports how many cubic inches one ounce produces after being compressed—so higher numbers generally mean larger clusters, more loft, and better warmth-to-weight. The article explains that fill power is a quality metric and must be read alongside fill weight to estimate warmth, and it covers how [[baffles]] design, garment construction, and available loft space affect real-world performance. It compares goose and duck [[down]], discusses ethical labeling like the [[Responsible Down Standard]], and notes innovations such as [[Outdoor Vitals]]'s [[Zero Stitch fabric]] that improve wind resistance. Practical care tips include storing uncompressed, using dedicated detergents like [[Granger’s Down Wash]], and slow drying with dryer balls. It urges checking fill weight and tradeoffs for backpacking.