Down Vs. Synthetic Insulation: Not All Insulation Is Created Equal

When you’re bundling up for the cold, the right fill counts. Should you go for the pillowy warmth of down or the weatherproof protection of synthetics? Our experts break down the difference.

Down Insulation

Down insulation comes from the soft, fluffy undercoatings of ducks and geese called “plumage.”

It is supremely warm and lightweight. It’s also easy to compress, or pack, without comprising the shape of your garment. This material naturally produces high-loft clusters that retain your body heat while maintaining breathability. It also wicks away moisture to keep you comfortable as you move. Simply put, down is Mother Nature’s best insulator.

In addition to all this, down is resilient: A down-stuffed jacket will likely deliver warmth for years if cared for properly.

THE TRADEOFF?
Down can’t get wet. If you’re trekking in dry conditions, down’s great—but get stuck in an unexpected rain storm?  Down loses its insulating power as soon as it’s exposed to moisture.

Synthetic Insulation

High-performance synthetic materials can mimic the qualities of down insulation without its susceptibility to water.

Synthetic insulation is often composed of polyester fibers, designed to replicate the effects of down. Most synthetic insulations are either water-resistant or waterproof, and some may even repel moisture. Synthetics also tend to be hypoallergenic, though you should always consult product information for details on individual products.

Plus, if your synthetic-filled sleeping bag or jacket gets dirty you can toss it in a washing machine for easy cleaning.

THE TRADEOFF?
Synthetic insulation can be bulky and heavy. It warms less efficiently, so it requires more weight to regulate body temperature. No man-made product can completely replicate the impressive warmth-to-weight ratio of natural down.

The lifespan of synthetic insulation tends to be shorter than that of down, though this can vary by product. Synthetic is also less compressible than down, and your garment may not hold its shape when it’s packed into your backpack or duffle.

TIP: Down jackets are labeled with a “fill rating,” generally between 500 and 900. The higher the rating, the warmer the coat. Some quilted jackets may be insulated with a combination of both down and synthetic fill.