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

Source: https://peakpinegear.com/guides/down-vs-synthetic-insulation
Published: 2026-07-27
Author: Peak Pine Gear Editorial Team

Warmth-to-weight, wet performance, price and longevity — an honest head-to-head, plus the one question that settles the debate for most hikers.

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.

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*See our favorite insulating layers on the [base layers & fleece page](https://peakpinegear.com/gear?category=base-layers), and keep the whole system dry with a shell from our [rain jacket tests](https://peakpinegear.com/guides/best-rain-jackets-2026).*