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Down vs. Synthetic Insulation: What’s the difference?

Author: Outdoor Research

October 31, 2017

Not all insulation is created equal, and deciding to kit yourself out for a specific adventure with down or synthetic insulation is a question we each ask ourselves over and over again. The answer largely depends on what environment you’re venturing into and what activities you’ll be undertaking. Whether you’re on a snowy belay ledge, thigh-mastering up a wet and windy peak, or layering up for an afternoon breaking trail with your favorite cross country skis, knowing when and where each type of insulation performs best will help you decide between these two types of insulation. 

Down Insulation
You might not believe us, but down is not made from feathers. Down insulation is made from goose or duck plumage – the lofty, fluffy stuff underneath the feathers. It is an undercoating, or a natural midlayer. Nature’s best insulation, down creates high-loft clusters that trap air and body heat. In addition to its ability to efficiently trap heat, down is also incredibly breathable, allowing it to wick unwanted moisture away from your body to evaporate.

Because of its supreme warmth-to-weight ratio and incredible compressibility—which makes it  very easy to pack—down is considered the crème de la crème of insulators. It remains lightweight and compressible while holding you in a cocoon of warmth, definitely something to consider when debating what to take on your trek and what to leave in the closet.

RELATED: Demystifying Down Fill Power

Down can be broken into a spectrum of effectiveness. We measure this effectiveness—“fill power”—by how many cubic inches one ounce of down can fill. The typical range is around 450 to 900, with 900 being the warmest and lightest… but also the priciest.

The warmest, lightest down comes at a premium price because it’s sourced from mature geese. This is the best insulator because the high-loft goose down has a very fine construction. Duck down is less fine than goose down and thus is less expensive, but also maintains slightly less loft.

Natural down is also incredibly resilient and—if properly cared for—can be used for many years. However, down has a few *ahem* downfalls: First, down is incapable of efficiently repelling moisture. In fact, it loses many of its insulating properties when it gets wet and is often slow to dry.

RELATED: How To Care For A Down Jacket

With all that in mind, if you’re faced with cold, dry conditions or if you don’t expect to encounter wet weather, then down insulation is your ticket. Plus—now you can shop with confidence, because OR stands behind the Responsible Down Standard.

Or—if you REALLY want the warmth of down regardless of the weather—you could consider the beefcake of down jackets, the Outdoor Research Floodlight II Down Jacket™ – a fully waterproof, down-insulated jacket made to take on the most insufferable conditions. We overcome the problems down creates in wet environments by stuffing 650 fill down insulation into a waterproof Pertex® Shield + fabric with seam ttaping, creating a truly waterproof down-insulated jacket.

Not waterproof, but water-resistant, the jackets in the Transcendent Down Series are lightweight down jackets filled with 650-fill down insulation sandwiched inside of lightweight 20D ripstop. Whether you're headed on a fall climbing trip or to the office, the Transcendent jackets are the classic option.

For the most packable warmth for the weight, the Illuminate Down Jakets and Hoodies are the lightest, warmest, easiest-to-grab midlayer pieces that pack 800-fill responsibly sourced down insulation into their own left-hand pocket. The perfect emergency layer to keep in your pack, the Illuminate series combines a sturdy nylon shell and lining provide with light weather resistance to make sure you don't wind up chilled at the top of that route that took you longer than you thought it would.

The next level of warmth, compressibility and durability can be found in the Alpine Down Jacket. With 800-fill down in a Pertex® Y Fuse body with Pertex® Quantum Pro sleeves, this is the burly layer to pack for high camp.

Synthetic Insulation
So now we know down is warm but doesn’t do well in wet or humid conditions. Enter synthetic insulation. Synthetic insulation is designed to replicate the qualities of down, but retain them even when wet. It’s made with polyester fibers that are arranged in different sized filaments and intertwined, mimicking down’s lofty clusters. These ultrafine fibers trap warmth in air pockets, providing great warmth… though not quite as good as down. In addition, synthetic insulation has a slightly higher weight-to-warmth ratio than down, meaning it needs to be heavier to achieve the same warmth as down. The upside to synthetic insulation is that it is much more resistant to moisture, and when it does get wet it dries faster; synthetic insulation can often dry within a day—maybe even hours—if put in the sun or on a windy day. And now, new fabric technologies like VerticalX™ and VerticalX Air™ offer increased breathability and moisture transfer, designed to be worn while you're on the move. Synthetic insulation also tends to be friendly on the wallet and is naturally hypoallergenic.

Tthe high-loft VerticalX™ insulation in our Refuge Jackets keeps you warm, dry, and comfortable even when wet. Water and wind resistant, with movement-mirroring stretch, these lightweight jackets are treated with Thermo-regulating ActiveTemp™, making them the perfect jackets to wear both wheen you're moving and when you stop.

Even lighter, more breathable, and quicker to drop excess heat than the original Refuge Collection, the Refuge Air is the layer you'll choose when you have fewer rest stops and a faster pace planned for a ski tour, snowshoe or winter hike. Supreme moisture management and breathability makes it the perfect choice for high-exertion activities.

Polartec Alpha is the fuzzy, superlight insulation in the Ascendant Series that makes these jackets the perfect mid-layer for leaving on despite your activity level, even lighter than the Refuge or Refuge Air lines. That same soft insulation wicks moisture away from your skin, keeping you from the cold, clammy mid-mountain break.

Our hybrid jackets—like the Vigor Hybrid Hooded Jacket, the Refuge Hybrid Hooded Jacket and the Women's Melody Hybrid Jacket—provide extra flexibility, combining hybrid-mapped synthetic insulation with lighter movement-enhancing construction for two-in-one performance and comfort.

If you're looking for an insulated ski jacket, the Fortress Jacket combines VerticalX™ insulation echnology with a 100% waterproof Pertex Shield shell. Designed for the coldest of ski tours, this jacket is waterproof, windproof, breathable and fully seam-taped, so you'll be ready for the gnarlist weather.

Outdoor Research

Outdoor Research® is dedicated to inspiring the journey ahead with award-winning technical apparel and accessories. Based in Seattle since 1981, we are committed to improving our customer’s experience through innovative materials, purpose-driven features, and versatile products that are backed by our Infinite Guarantee®. We rely on the real-world testing of our athlete ambassadors, mountain guides, and local adventurers involved in our core sports: alpinism, rock and ice climbing, hiking, backpacking, paddling, trail running, and backcountry skiing and snowboarding. We’re here for the fun, adventure, excitement, and For the Journey Ahead™. Get to know us at www.outdoorresearch.com or follow along on the journey via Facebook, Instagram, Twitter, and YouTube.