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Synthetic vs. Down: Which is Best for Your Thru-Hike?

The two most popular insulators are made from synthetic fibers or down. When preparing for your thru-hike or backpacking trip, you should know which type of insulation is best for your needs.

Paul Bodnar       Educational       7/26/2021
Paul Bodnar
Educational
7/26/2021

Insulation

Insulation is essentially air captured in the material clusters. A jacket or sleeping bag that more effectively captures and retains heat generated from the body has better insulation.

fibers under microscope

Fleece Fibers (Synthetic)

Fleece is made from polyester fibers which are synthetic. Fleece is a comfortable but tough durable fiber that allows moisture to evaporate. The image shows the thick fleece fiber up close. Fleece is made by weaving these thick fibers and the brushing them into a fluffy thick fabric.

Fleece fibers are shown at about 25x magnification. One white square is 5 mm by 5mm (about 0.2 inches by 0.2 inches).

Large Fleece Jacket Weight: 586 grams (20.7 ounces)

Fleece Blanket (70 x 54 inches) Weight: 1559 grams (55 ounces)

Pros

  • Affordable and durable

Cons

  • Heavy, poor insulation, and doesn’t compact well
fibers under microscope

Thin Synthetic Fibers

The image shows the thin fibers extracted from a synthetic puffy jacket. The thin synthetic fibers take up a lot of volume and fill up a lot of space. These thin synthetic fibers provide much more warmth than fleece.

Synthetic fibers from a puffy jacket are shown at about 25x magnification. One white square is 5 mm by 5mm (about 0.2 inches by 0.2 inches).

Large Synthetic Puffy Jacket Weight: 454 grams (16.0 ounces)

15°F Synthetic filled sleeping bag Weight: 1446 grams (51 ounces)

Pros

  • Affordable and compact

Cons

  • Heavier and less insulation than down
fibers being examined

Down Insulation

The image shows down (800-fill-power) extracted from a down jacket. Down creates thousands of small air pockets that trap warm air. Down is not only a great insulator but also compacts to a very small size.

Down is shown at about 25x magnification. One white square is 5mm by 5mm (about 0.2 inches by 0.2 inches).

Large Down Puffy Jacket Weight: 378 grams (13.3 ounces)

15°F Down Sleeping Bag Weight: 936 grams (33 ounces)

Pros

  • Best insulation, easily compacts, and lightweight

Cons

  • More expensive and poor insulation when wet

Summary

Out of all the insulating materials down still remains the best. Down has a warmth-to-weight ratio about two times that of synthetic insulation. Down is also lighter and compacts better than the synthetic materials. However, down is much more expensive than synthetic insulation.

Most long-distance backpackers and thru-hikers select down as their insulating material. The best insulation for your hike will depend on your personal hiking needs.


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Photo courtesy of the Tahoe Rim Trail Association

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About the Author
A man wearing an Arizona Trail baseball cap stands in a field in front of a mountain.

Paul Bodnar

Paul has always liked hiking and thru-hiked the Pacific Crest Trail in 1997 after college. After years of working in chemistry, he wanted to create a career involving the outdoors, so he hiked the Pacific Crest Trail again in 2010 to do research for his guide book Pocket PCT. He realized that creating a smartphone app for navigating the outdoors would make it easier to keep the data current and provide a better way to navigate. While hiking with Ryan (aka Guthook) in 2010, they decided to work together to create the first comprehensive smartphone guide for the Pacific Crest Trail. Now with the help of a team of great people they have created over 50 guides for trails around the world.