By the Numbers: Compression Resistance of PrimaLoft Gold vs. Climashield Apex (Part 4)

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Home Forums Campfire Editor’s Roundtable By the Numbers: Compression Resistance of PrimaLoft Gold vs. Climashield Apex (Part 4)

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    Stephen Seeber
    BPL Member


    Companion forum thread to: By the Numbers: Compression Resistance of PrimaLoft Gold vs. Climashield Apex (Part 4)

    PrimaLoft Gold outperforms Climashield Apex as the more resilient (durable) insulation, capable of retaining more of its original warmth and loft in response to repeated compression.

    Jeff McWilliams
    BPL Member


    Locale: Midwest

    That’s super interesting.  The traditional wisdom was that Apex degraded less than PrimaLoft.

    My speculation is that PrimaLoft has done their homework and over time changed the formulation of their insulation so that it resists loss in loft due to repeated compression.

    Cool stuff!

    Stephen Seeber
    BPL Member


    Hi Jeff:  Thanks for reading.  I agree with this.  ln their original patent they described the fiber diameter mix that provided “durability” as well as excellent warmth for synthetics of the time.  Since that time, they have  changed the fiber mix to reduce proportion of thinner fibers while increasing the diameter of the largest fibers.  My guess is that PrimaLoft is not as warm as the original formulation but is now far more durable.

    Erik Norseman
    BPL Member


    Locale: Okanagan

    Hi Stephen! Thanks for this. Amazing work, as always. The obvious question you mention at the end still keeps my wondering, namely, how synthetics these days compare to down. Certainly an interesting topic. Down loses loft, too, as it gets dirty etc., but can maintenance prevent that? Synthetics are “warm when wet,” but we know that nothing is comfortable or really warm when wet… boxwall vs. sewn through for down, synthetics have fewer seams… the options are endless!

    For your results, how do we make real world conclusions from it? How significant would the perceived loss in warmth be from, say, 0.8 decrease in R-value or a 0.8″ decrease in loft? Does anyone have some experience to chime in here? My sense is that 0.8″ loft is significant and noticeable, whereas ~0.4″ perhaps not so much. It would be interesting to identify the “just noticeable difference” in loss of loft/r-value to get some context.

    Great read as always.

    Also a note–figure 6 is repeated and figure 7 appears to be missing.


    BPL Member


    Nice writeup Steven!

    As noted above, this runs counter to the lay wisdom that Apex was not as warm as Gold but more durable. This seems to show the opposite – warmer but less durable. That begs the question of the degree to which Apex and/or Primaloft has changed — or whether the lay wisdom was ever correct to begin with!

    If nothing else, it gives me comfort that I hung onto some Gold-insulated jackets. They’re of relatively recent vintage so hopefully they have the more durable variety of Gold shown here.

    Eric Blumensaadt
    BPL Member


    Locale: Mojave Desert

    Call me surprised. In past years Climashield was better at retaining loft after compression than Primaloft products but this test shows the newer Primaloft GOLD is superior. No wonder LL Bean uses it in their garments. Bean tests materials well before putting them on the market because they have a good reputation to maintain.

    Brian E
    BPL Member


    Hi Stephen, I am super interested in a chat with you regarding your methodology for the test data. Please reach out to me at [email protected].




    Locale: Cascadia

    Here’s a major wrench to toss into the works…

    Apex has a very large production variation in quality control in regards to both the distribution of fibers over an even area, and the stiffness of those fibers.

    I have ordered quite a few sheets of Apex in various weights. Sometimes the fibers can be extra course or fine on some cuts of Apex. This is obvious in the surface feel. Some can have a rough surface feel, while others are soft. I’m not entirely certain to what is causing the variation, but it is 100% without any doubt very discernible just with handling them.

    Tests like this probably need to be conducted in aggregate over a larger random sample size, eh? Quality control variation could have an impact when looking at deltas between numbers that already pretty close to within the margin of error.

    I think that uncertainty can put a lot of question into tests done with limited sample size. This exact same testing issue happens often with camera lenses. Lens Rentals has amazing articles on sample variation and testing protocols with camera lenses, that also applies to most manufacturing of consumer goods.

    Jerry Adams
    BPL Member


    Locale: Oregon and Washington

    it seems like thinner apex, like 2.5 oz/yd2, has more variation.

    I have to select areas that don’t have voids

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