Down vs Synthetic Sleeping Bags: Which to Buy?

The insulation inside your bag changes how it performs in the real world. Here is how down and synthetic stack up where it matters.

At a glance

When down wins

Down is the choice when weight and pack size matter most. For a given warmth rating, a down bag is lighter and stuffs smaller — a real advantage for backpackers counting grams. In cold, dry conditions it is unbeatable, and a quality bag lasts for years.

Browse warmth ratings and picks in our best sleeping bags and pads guide.

When synthetic wins

Synthetic insulation keeps you warm even when it gets damp, and it dries quickly — ideal for wet climates, canoe trips, or humid nights. It also costs less and shrugs off rough handling, which makes it a smart pick for kids and casual campers.

What about hydrophobic down?

Treated, water-resistant down narrows the gap by resisting moisture and drying faster than untreated down. It is a genuine improvement, but it still costs more than synthetic and is not a substitute for keeping your bag dry.

The verdict

Backpackers in dry, cold country who want the lightest kit should choose down. Campers on a budget, in wet weather, or buying for kids are better served by synthetic. Either way, store the bag loosely to protect its loft.

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Frequently asked questions

Is down or synthetic warmer?

Per pound, down is warmer. For the same temperature rating, a down bag is lighter and packs smaller than a synthetic one.

Which is better in wet weather?

Synthetic. It insulates even when damp and dries quickly, while untreated down clumps and loses loft when wet.

How should I store a sleeping bag?

Loosely, in a large cotton or mesh sack — never compressed long-term. This protects the loft of both down and synthetic bags.