It’s common to assume that fill weight and fill power are the same thing – here’s the difference. Fill weight is a measurement of how much material, in terms of ounces, is put in the bag’s shell. Fill power is a measure of the quality and cubic inches, so the higher the fill power, the higher the quality and the larger the down cluster.
So, does that mean the higher the fill power, the heavier the bag will be? It can actually mean the opposite! Often times, a higher fill power means a softer, lighter down.