1, goose down is bigger than duck down, indicating that goose down pants can hold more air and form a better warm layer. Air is a good insulator, which can prevent the loss of heat, so goose down pants have an advantage in keeping warm.

2. Fluffy is an important index to measure the thermal performance of down, which indicates the volume of down per unit weight in natural state. The fluffy degree of goose down is higher than that of duck down, which means that goose down pants can provide better warmth and are lighter and softer. So goose down pants keep warm.