Down jackets provide an excellent warmth-to-weight ratio and pack down small, making them popular for hiking, travel and cold-weather layering. They perform best in dry cold or when protected by a shell, because untreated down loses insulating efficiency when saturated.

Compare fill power, total down amount when listed, construction, outer fabric, weather resistance and intended activity. Higher fill power means more loft for a given weight, but it does not tell you the jacket’s total warmth by itself. Baffle design and the amount of insulation are also important.

Fill power measures the loft and efficiency of down, not a temperature rating. A 700-fill jacket can be warmer than an 800-fill jacket if it contains more down. Stitch-through construction saves weight, while box-wall baffles reduce cold spots but are usually heavier and more complex.