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

[Stephen Seeber]

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]

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]

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]

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.

Cheers!

[Chris]

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]

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]

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].

thanks/Brian

[YoPrawn]

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]

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

I have to select areas that don’t have voids

[David D]

Stephen, hoping you can help clear something up.

The graph shows Apex bottoming at ~ R 2.3 (same as Primaloft Gold) but the table shows R2.1.

In the market for an Apex quilt for corner seasons and wondering how much warmth I’ll lose cramming it into a tight compression sack, to help choose the right temp rating.

[Stephen Seeber]

David: I have reviewed my spreadsheet for the article. It contains two tables containing the R-value and loft test results. All data in the two tables are identical except for the R-value for test 30.  In the second table, the average is 2.1 and in the first, 2.31.  The plot reflects the 1st table.  I can’t explain this discrepancy.

Depending on which table is used, the values are a little different for the 30th test, but the conclusions are not: Apex degrades in this test more than Primaloft.  Apex continues to degrade slowly with increased stuffing, but the rate of degradation, as seen in the average plot, becomes more stable as the stuffing accumulates.

Regarding what to expect with your “cramming,” that is not quantifiable since I have no idea how much force you plan on using.  My test suggests that the amount of force used for stuffing has limited bearing on the rate of degradation.  More critical is the number of stuffs.  The plot shows a loss of 28% of warmth (or a little less if you use the  R2.3 value).  If you stuff lightly with a larger stuff sack, I expect you would get less degradation.

[David D]

Hi Stephen, thanks for these results.  It’s great having these theories put to test

The R value stabilizes to a flat line best modelled with an exponential.   Sample variation may account for the differences in two test outcomes for Apex.

I created a model based on industry papers that I hope to publish some day.  I estimated the following equivalent bag temp rating changes with the R value degradation, except based on a similar degrade in sleeping pad R value (what the model tracks).  Not an exact equivalence but I think close to reality.

All in all, a lot better than I thought and the warmth difference between Apex and Primaloft Gold after many compression cycles is a wash.  Too bad no one makes UL quilts out of Primaloft Gold. 20deg rated Apex quilts are huge in the pack

R= 2.9 (Apex starting point): reference

R = 2.6 (Primaloft Gold start): ref+0.8F

R = 2.4 (Primaloft Gold end): ref+1.6F

R = 2.3 (Apex end in one test): ref+1.8F

R = 2.1 (Apex end in another test): ref+2.5F

 

[Jeff McWilliams]

Apex is made as a single sheet and makes it easy to build synthetic quilts out of it.  I’ve made several.

I believe Primaloft Gold requires quilting every 6″ at minimum, which probably decreases the ease of manufacture and cost advantage of using synthetic vs down.  (just a guess)

There was a company called Cedar Ridge Outdoors that made quilts out of a different loose synthetic insulation called “Up”.  CRO went out of business roughly 14 months ago.

You can still buy Up insulation from Dutchware Gear, and maybe others.

Primaloft Gold is also more expensive.

3.6oz Apex is 11.00/yd from Ripstop

3.0oz Primaloft Gold is 17.25/yd from Quest Outfitters.

Because Up is sold by the ounce and not by the yard for a given weight, it’s hard to compare the cost apples-to-apples.

 

 

[Stephen Seeber]

Hi David:  I suspect Jeff is correct.  It must cost far less for manufacturers to work with Apex compared to Primaloft.

In terms of curve fit, polynomial provides an excellent fit for Apex-R value and loft.  For Primaloft, Linear or Polynomial provide similar fits for the R-value.  Polynomial provides an excellent fit fot Primaloft loft changes, but, as I discussed in one of the articles, there something else going on with the loft.

I know what you are thinking:  how would these look with another 20 or 30 crushes? It is going to take someone else to figure that one out.

I look forward to what comes from the work you are doing with industry papers.

[David D]

Jeff, Stepehen, great info on Primaloft Gold, thanks for explaining the costs.

It’s a small market for performance synthetic sleep systems.  Fowl allergies make cold weather lightweight backpacking a challenge

Quilts are criticized for being drafty and cold below freezing but when your only option is synthetic, they start to make a lot of sense especially if a side sleeper.

Just as way of example, I have a Marmot Trestles 20 deg mummy bag (comfort ~ 32 deg) which at 2lb 6oz is as light as you’ll find for a synth 20 deg bag.  These synth mummy bags have much less insulation underneath but their dirty little secret is that the top half is ridiculously narrow.  The Marmot top is 33″wide so side sleeping causes the back to have a foot of very modest back insulation covering it, freezing below 40 deg.  No way around it.  Only back sleeping is warm into the upper 20s (with some fleece).  For comparison, an EE wide quilt is 58″.

The other dirty little secret of “lightweight” synth mummy bags like the Trestles is that they use 40D or worse nylon inside and act almost like a VBL to hold in the heat.

So they meet their temp ratings by forcing back sleep with little maneuverability and making it very clammy.

I almost bought one of CRO’s UP! quilts in ’23 but missed out.

I’ll try a 20 deg Revelation Apex this fall.  It’ll only save a modest amount of weight but should provide a much better sleep.

[Terran Terran]

I see an Eno quilt with Primaloft. Gold and black.
Material:
Insulation: Primaloft® Gold (100g) + Primaloft Black (80g)
Shell: 20D Ripstop Nylon
Lining: 30D Nylon Taffeta
Dimensions:
6’6” x 4’5” / 2 x 1.4 m
Packed Dimensions:
Storage Bag: 15″ x 11″ x 11″ / 38 x 28 x 28 cm Stuff Sack: 12″ x 7″ x 7″ / 30.5 x 18 x 18 cm
Packed Volume:
9.6 L
Weight:
28 oz / 801 g

[Jeff McWilliams]

Interesting about the Eno quilt!

David D – When it comes to draft management when using quilts, I’m intrigued by the idea of retrofitting at least one of my quilts with loops to match the Zenbivy Ultralight Sheet and using them together.  If it works well with a down quilt, why not a synthetic one?

You know what else we don’t see in the market?  Features like draft collars on synthetic quilts.  Enlightened Equipment doesn’t offer the option.  It looks like the Eno Vesta sorta has one in the drawstring footbox but I don’t see one around the neck.  I don’t know how to make draft collars personally but I’ve made three APEX quilts.  I wonder how difficult it would be to incorporate a draft collar filled with Up insulation around the top and something similar in the drawstring footbox.

If such a quilt were coupled with a Zenbivy sheet, would it feel significantly warmer than your average off-the-shelf synthetic quilt?

 

[Bill Budney]

Has anyone here looked into the G-Loft insulation used by Carinthia? They claim that it recovers better from compression and performs better than other synthetics when wet. G-Loft is an Austrian company.

I don’t know which variant Carinthia uses, and I don’t know how G-Loft stacks up against Primaloft or Apex. I mention it because of their claim about superior resistance to compression.

Carinthia has a good reputation for the quality and performance of their synthetic gear.

That’s about all I know.

[David D]

TT, thanks, that one was under my radar.  I’ll need to estimate the temp rating to double check their “30 to 50 comfort” claim

Jeff, I considered a pad sleeve (have a spreadsheet somewhere…) and found it makes the system quite heavy once factoring in the weight of synthetic insulation.  People love their Zenbivys so it makes a lot more sense for down.

If you add a collar, the Trestles design is worth copying, its small and well placed and just works.  The Forte’s is gigantic and impossible to disengage without covering up the face.

Here’s a weight breakdown of some synth options for < 50F nights suitable for side sleepers.  I’m currently using a 20 deg Trestles but don’t like it, and I think I’ll just bite the bullet and buy a 20deg Apex EE even though it only saves 3 oz.  My warm weather bag is the Forte and I love this thing, but I’ll probably pick up a 30 deg or 40 deg EE Apex (or that Eno) and drop a bunch of weight.

I got fooled into the Trestles by Marmot.  I asked their customer support if the bottom used as much insulation as top (I have bags like this) and they falsely said “yes”.  But reality is you can’t roll or side sleep in it, and its very clammy because of the 40D liner.

[Bill Budney]

Carinthia G-180, 25F comfort, 38.3oz, 5.8L, claims to be impervious to compression.

Shrug… if you really want to compress it hard and often, G-Loft appears to be worth a look.

[David D]

Bill, thanks for the suggestion.  Some open questions on the Carinthia:

– is the bottom well insulated for side sleeping?  Looks like no

– what is the breathability of polyamide fabric?

– does the internal reflective layer (Thermoflect) make it sweaty and clammy?  Looks like it would

I’d personally want to see these questions addressed before I took the risk for $500Can+shipping from Europe, especially since its no lighter than an Apex 20 wide @ $330 Can+domestic ship

[Bill Budney]

I would ask different questions: “What companies use G-Loft”, and “do any of them make ultralight gear?”

When I first read this article I did a web search on synthetic insulation and compression. I stumbled onto G-Loft, and the discussion I read sounded as though G-Loft might be superior in lifetime warmth: weight. I don’t recall the source, but it gave the history of G-Loft and it was fairly persuasive. I seem to recall fill power at the high end of the range for synthetics — almost as good as very inexpensive down.

I chalked it up as “interesting” then moved on (because I am not allergic to down).

I spent two minutes looking up an example on the Carinthia website because I recalled that they use G-Loft, and owners of Carinthia gear seem almost unanimously happy with the brand.

I’m not recommending a specific bag or manufacturer. Just pointing out that I would research G-Loft further if I WERE allergic to down.

A couple of other thoughts:

Nylon is a polyamide. Breathability ranges from excellent to not at all.

Reflective is not necessarily clammy. The reflective Tyvek (or whatever it is) in the SOL Escape Bivy does not appear to be. (However, Stephen points out that “visibly reflective” does not necessarily mean “IR radiant blocking”. )

If G-Loft is as good as claimed, then it might be roughly 25-30% better than Apex in lifetime warmth: weight. However, it is made in a distant land, so $: warmth or $: weight may be less appealing.

So I cannot answer all of your questions. This is a lead — not a specific product recommendation.

Perhaps one of our European readers may be able to fill in some of the missing pieces?

 

[David D]

I checked out the Eno at a local shop.  It looks well made and the Canadian price is great (I think they’re from up here).

The 30D liner wasn’t breathable in the mouth blow test but I was able to fully cinch the footbox.   It’s very light for synth.  It didn’t have pad straps but there were fabric loops to manually add something.  Not as turn key as an EE.  It didn’t come in a wide version so is better suited for back sleepers.

The shop hadn’t sold many yet so were still unopinionated, but it looks like a viable option for back sleepers above ~ 40F but that’s just a guess.  It would be great to see one get the ISO test

[Jeff McWilliams]

My guess:  the Eno quilt lacks pad straps and extra width because it’s meant for hammock users.  I don’t need straps when I’m hammock camping.  It’s easy to tuck the edges of my top quilt between  my body and the hammock fabric, which is pressed up against my sides and keeps everything in place.  Combined with an underquilt, there aren’t draft issues in a hammock when using a top quilt the same as when sleeping in a tent on a sleeping pad.

 

[David D]

That also makes me wonder about their comfort rating.  On-spec pad/quilt comfort ratings assume a R4.8ish pad (+/- there’s latitude in the spec) and a light base layer.   I have no idea what the equivalent underquilt in hammock “R-value” would be when they estimate the top quilt temp rating.

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