Eddie Bauer is releasing a 1,000-fill puffy in October, and the North Face will debut a collection of Advanced Mountain Kit jackets and insulating pants warmed by 1,000-fill down next spring.

A jacket with 650-fill down takes up less volume than one with 1,000-fill down, so it’s denser and has less space for warm air. But when it comes to warmth, what really matters is how much of ...

Have you run across the term “down fill power” while shopping for sleeping bags, puffer jackets, or a duvet?These numbers range from 450 to 900, and sometimes above. Generally—but not always ...