Down vs Synthetic Insulation

Down is warmer per ounce, packs smaller, and lasts longer. Synthetic keeps insulating when wet and costs less. Almost every real decision comes down to how confident you are about keeping the bag dry.

1. 1

   Warmth to weight: down, decisively

   Down's loft per ounce is roughly twice that of synthetic fill at equivalent warmth. A 20°F down bag might weigh 1lb 8oz where a synthetic equivalent is 2lb 12oz. Over a multi-day trip that difference compounds with the pack volume it also saves.

2. 2

   Wet performance: synthetic, decisively

   Wet down clumps and stops insulating almost entirely, and it takes days to dry in the field. Synthetic retains a meaningful share of its insulation when wet and dries far faster. In persistently damp conditions this is a safety consideration rather than a comfort one.

3. 3

   Understand what treated down changes

   Hydrophobic down is treated to resist moisture and dries faster than untreated down. It genuinely helps in damp conditions and it does not make down behave like synthetic. Treat it as buying margin, not immunity.

4. 4

   Lifespan: down, by a wide margin

   Well-cared-for down retains loft for 10-15 years or more. Synthetic fills compress permanently and typically lose meaningful loft within 3-5 seasons of regular use. Amortised over that lifespan, down's higher purchase price often works out cheaper.

   Washing and storageHow to get fifteen years out of down

   Read Guide →
5. 5

   Decide by climate and confidence

   In dry or cold-dry climates, or if you use a good pack liner and a shelter you trust, down is the better buy. In persistently wet climates, for boat or canoe trips, or for beginners still learning to keep gear dry, synthetic is the safer choice.

Head to Head