Recently an acquaintance asked me to help him find a suitable down jacket for backpacking when nighttime temperatures could dip down to 20° F (6.7° C). He wanted a 900 or higher fill power garment because, “The higher the fill power, the warmer the garment.”

But is this true? All things being equal, not really. The most important factor is the thickness of the insulation, not fill power.

In this post I will explain fill power, insulation thickness, and the difficulty of shopping for suitable equipment because the equipment manufacturers (clothing, sleeping bags, and quilts) try to confuse us with worthless marketing instead of useful facts.

Continue reading Down Fill Power Explained — Is it an Important Measurement? →