Insulation geekiness: specs, pros & cons, optimal uses || SD LIVE (September 8, 2015)

Live recording

SD Live: All Things Insulation from Sierra Designs on Vimeo.

Episode overview

In the September edition of SD LIVE, we focused on the insulation materials most commonly used in outdoor apparel and sleeping bags, specifically fleece, down, and synthetic fills. Frank Kvietok, who manages the Advanced Development Center at Exxel Outdoors and who was the mastermind behind DriDown, joined me and Sierra Designs Brand Manager Michael Glavin in order to provide another level of detail and insight.

While this video is packed with information, it’s typically not a geek-fest. We tried to stay focused on content that is both useful and relevant:

  • Sources
  • Specs
  • Pros & cons
  • Myths
  • Terminology
  • Optimal uses

Happy watching! If you have additional questions, leave a comment below. I’ll get to it.

Posted in on October 21, 2015
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  1. Tom on October 22, 2015 at 1:56 pm

    I had to skip ahead to 5 min, hope that saves someone else some clicks. Good info.

  2. Taylor on October 27, 2015 at 10:46 pm


    Not meaning to split hairs with this question, I’ve seen synthetic layers often used underneath hardshell jackets in inclement weather on mountaineering trips. I think there is perhaps a more delicate balance needed in layering system where high-output activities alone will not keep the body warm in extreme temperatures without a high-loft insulating layer, but a hardshell jacket would be needed on top to shield from precip. Would you say synthetic insulating layers hold no benefit over down in terms of thermoregulation in this instance? This would apply mostly to the “warm pee” reference where you talk about scenarios where you would have warm moisture and how it would affect down vs synthetic.

    • Andrew Skurka on October 28, 2015 at 10:41 am

      A few thoughts:

      1. If it’s so cold that you need to be wearing a high-loft insulated jacket or pants while moving, you probably don’t need a hardshell jacket. At those temps, the snow is really dry, and a less water-resistant shell (that is also more breathable) will work fine. This will reduce the amount of moisture trapped in your system.

      2. When I’ve worn a hard shell over a high-loft piece in really cold temperatures, the moisture seems to collect (at least most visibly) between the inside of the shell jacket and the outside of the puffy. You’ll see it as frost. This is what happened to Sam in this photo, though the frost is hard to see.

      3. In really cold temps, I transition into vapor barrier liners.

      • Taylor on November 1, 2015 at 1:58 pm


  3. John on November 1, 2015 at 7:37 pm

    Andrew, When you are sleeping at or below dew point what about reversing your down sleeping bag/quilt each night on multi-day trips to move moisture through the bag i the event you don’t have any dry moments for days on end?

    • Andrew Skurka on November 3, 2015 at 11:16 am

      If you didn’t compress the bag/quilt into a sack each day, this might help some. But with that compression, the moisture moves throughout the bag.

      • John on November 3, 2015 at 10:40 pm

        Great point. I had not considered the compression of the bag/quilt each day.

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