Down insulates by trapping air and is prized for being light, easy to compress, long-lasting and breathable. It’s the insulation of choice in cold, dry conditions, or whenever reducing weight and saving space are top priorities.
Down insulation type has typically been sourced from geese. However, many major manufacturers switched to duck down in recent years due to the cost of goose down. All testing and performance standards are the same for duck down and goose down, so either way, you can be assured you’re getting a high-quality product. However, you’ll find that goose down insulation type often is still used in the highest-end products because it can reach a higher fill-power rating than duck down.
Typically made of polyester, synthetic fill insulation type is quick-drying and insulates even if wet (something down struggles to do). It also tends to be less expensive than down insulation, and it’s durable and hypoallergenic.