What Is Fill Power In A Down Comforter?

Fill power is the most frequently used measure of down quality. Fill power is a measure of the space or fluffiness of the down clusters in a comforter and is expressed in cubic inches per ounce. That is, how many cubic inches per ounce do the down clusters occupy?

Fill power ratings range from:

■400–500 for medium quality down,

■500–550 for good quality down,

■550–750 for very good quality down and

■greater than 750 rated down is considered excellent.

In summary, the higher the fill power, the better the insulating ability, warmth and quality that a down comforter will have.