Down vs. Synthetic Insulation: Which Jacket Should You Buy?

Every fall the same question floods our inbox: down or synthetic? After a decade of wearing both in everything from dry Colorado cold snaps to sodden Cascade sleet, here's the honest answer.

The 60-second verdict

Buy down if you mostly camp in dry cold, count ounces, or want a jacket that lasts a decade. Buy synthetic if you expect to get wet, hike hard while wearing it, or want to spend under $200.

Where down wins

Warmth-to-weight. Nothing beats quality goose down. A 7-oz 850-fill jacket is as warm as a 14-oz synthetic — and packs to the size of a grapefruit. Longevity. Down keeps its loft for 10+ years with basic care. Synthetic insulation loses measurable warmth after 3–5 years of compression cycles. Packability. For the same warmth, down compresses to roughly half the volume.

Where synthetic wins

Wet performance. Modern synthetics (PrimaLoft Gold, Coreloft) retain most of their warmth when soaked; wet down collapses into cold clumps. In sustained drizzle, it's not close. On-the-move insulation. Synthetics breathe better under exertion — that's why active-insulation jackets exist. Price and care. Synthetic jackets run $100–250 vs $250–450 for quality down, and they tolerate regular machine washing.

What about hydrophobic down?

Down treated with a DWR (Nikwax, DownTek) resists moisture meaningfully better than untreated down — it buys you an hour or two in light precip. But it still doesn't match soaked-synthetic performance, and the treatment fades with washes.

Fill power, decoded

Fill power measures loft per ounce: 650-fill is solid value, 800+ is premium. A 900-fill jacket isn't 50% warmer than a 600-fill one — it's the same warmth for less weight. Prioritize total fill weight and construction over chasing numbers.

Frequently asked questions

Can you wear a down jacket in the rain?

Briefly, under a shell. Sustained rain without a hardshell will wet out even hydrophobic down. In wet climates, always pair insulation with a real shell.

How do you wash a down jacket?

Front-loading machine, down-specific soap, gentle cycle, then tumble dry low with dryer balls until fully lofted — often 2+ hours. Never dry clean.

Is synthetic insulation vegan?

Yes — and it's also why some buyers choose it. If you buy down, look for RDS (Responsible Down Standard) certification.

---

See our favorite insulating layers on the base layers & fleece page, and keep the whole system dry with a shell from our rain jacket tests.