For breathability, we employ the reputable sweat test
After The North Face’s retail launch of their new FutureLight fabric, I felt it was time for a test with some real science behind it. Afterall, there are dozens of gear review websites with testing laboratories that I can only assume are filled with all the latest and greatest gadgetry for non-biased results (BTW: does anyone know where I can calibrate my arm for flex testing skis?). Since the WildSnow DIY waterproof tester is still a pile of PVC pipe and bailing wire in Lou’s garage, I contacted a third party lab to do some truly unbiased testing.
But after receiving the lab’s astronomical price quote, I decided to leave that to the professionals and go back to testing gear the only way I know how: put the jacket on, thank The North Face for their on-going support of WildSnow, and run through the mountains while carefully and systematically documenting the way the gear makes me feel.
Beginning in November 2018, I’ve logged an entire season in FutureLight. From standing on the top of Colorado’s windiest fourteeners, to baking on the flanks of spring Pacific Northwest volcanoes, and even getting poured on for several aborted ski missions, FutureLight kept me dry. The most significant observable feature through a season of testing was how little I thought about whether the jacket was on or off. But how would it hold up in warmer temps, when breathability was at its most crucial?
Test design
All hope of “science” was not necessarily lost — I devised a test that could give the reader some real insight into the uniqueness of this new garment. After a season spent skiing in the new FutureLight jacket, I figured a summer running test was in order to prove the actual breathability. The test track would be up the infamous Red Hill, whose rust-colored bulk can always be seen looming behind the town of Carbondale. I planned and conceptualized the study at the beginning of the summer, thinking it would be simple to slide this test into my intended summer running regimen in preparation for the ski season. However, I awoke a recent morning to snow in the mountains and a calendar date that had mysteriously slipped to the middle of October, and I realized that it was high time for my first fall training mission.
The actual Test
For the Red Hill running study to be completely objective, I would leave no stone unturned in my quest for data. For a control, I decided on an older model Gore-Tex Pro Shell. Long the industry standard, the backing fabric and brand name have been left anonymous for fear of legal repercussions. For the test piece I chose the Summit L5 LT FutureLight jacket.
I also took into account every variable to ensure 100% consistency — or at least document the differences for the ever-discerning WildSnow reader. I watched the weather like a hawk for the conditions to line up just right on two subsequent days. Finally, I saw my weather window. The time had come to wheeze while running uphill wearing a shell.
Variables kept 100% consistent
Testing Track: 2.5 miles, 850 vertical feet
Control Wardrobe: Shoes: Dynafit Feline UP trail runners, Shorts: Technical elite Ultimate Frisbee brand, Base Layer: Grey Dynafit 100% cotton t-shirt for maximum sweat ring visibility
Poles: Carbon Fischer Transalp, slightly bent on left pole
Variables up for some interpretation
Pre-hydration
FutureLight: 1 liter of coffee, 0 liters of water
Control: 1.3 liters of coffee, 0 liters of water
Pre-dehydration
FutureLight: .8 liters of wine the night before
Control: 1 liter of Eddy Line Brand IPA the night before
Temperature
FutureLight: 66 Degrees
Control: 58 degrees
Humidity
FutureLight: 28%
Control: 22%
Test Garment Color
FutureLight: very light gray
Control: black
Results Time (minutes)
FutureLight: 19.02
Control: 18.45
Ok, if you have made it this far into the article, you know that this is not the most “objective” or “lab tested” review of FutureLight on the web. This is just one out-of-shape reviewer’s take on a garment while he reflects with bewilderment on where a summer went. There were times I had even considered bringing a spray bottle to make it a full an obvious joke at the top. But, in the end, there was at least some merit to the test.

Testing FutureLight breathability on the Red Hill escalator.
The results
During the FutureLight testing, I delighted in not actually feeling the jacket while running (but maybe I was distracted by the effort to breathe and maintain uphill momentum). When taking the jacket off, I had light but visible sweat stains in the armpits, shoulders and back of my t-shirt.
However, when pulling off my jacket on the day of control testing, I was blown away (and my photographer disgusted) at the noticeable difference in sweat. It showed up in dark dense pools on the grey cotton t-shirt. The sweat shown in these photos is 100% real even if the measurements of hydration and actual ascent time are significantly exaggerated.
Conclusion (and reality check)
When all scientific measurements and calculations have been stripped away, we merely have our own opinions, emotions, and personal taste for making, what is, all joking aside, a critical decision about layering in the mountains. In the touchy feeling portion of the this review the literal observation made for both touching and feeling are noticeable. FutureLight is soft enough to run in without feeling it scratch on my bare arms, while being stretchy and silent enough that you don’t think about it. When suffering uphill on my first trail run of the off season and my first time running with poles since high school, it certainly removed the distracting level of discomfort experienced while running uphill in the control jacket.
Referring back to the months of winter testing, it is important to note that this is an active piece. When starting a tour thousands of feet below a summit in warmer temps, a base layer would be all I needed to start the day off moving. As I approached windier ridgelines and summits, the FutureLight shell came on once and then I would not so much as adjust a zipper for the rest of the climb. Although I never needed a burlier jacket while moving fast in high places against agonizing winds, the external air permeability is noticeable. This would not be my number one shell choice for hunkering down in a gusty wet storm for the long shiver bivy. There are some beefier FutureLight jackets that could work better in these conditions at the cost of a bit of extra weight. In spite of my personal fitness level jokes, I consider efficiency in the mountains to be the most important feature of every piece of gear.
For those crafty consumers that notice this was a sweat test and not a waterproof test, I can promise a very sad looking timelapse video of me getting poured on as soon as it rains in Colorado again. Until that time, as the nights get colder and as the time for cross training ticks away, the L5 LT FutureLight continues to offer amazing breathability and temperature control for the aspiring fast and light mountain athlete.
18 comments
It’s scholarly pieces like this that keep me coming back. Good show, DS…
Curious if anybody else in the outdoor world is using similar fabric from the FutureLight factory…I had a big-wig from another brand claiming they were using “the same fabric as Future Light” in one of their garments. What?! This would be a scandal if it were true. Put that professional on-staff writer over there on the case.
Curious about this stuff, maybe I’ll five-finger one of Mikey’s pieces this fall….stay tuned. Keep training, dude, hope to see you this winter!
Rob. Not possible that another brand is using our fabrics. Thanks. SM
Scott! I assumed as much, call it “textile envy.” Ha! Sounds like you guys are getting the goods over there….it’s been snowing up high on/off for two weeks here…cracks are filling in…..hope to see you here in spring! RC
Indeed. Would love to connect in Cham this Spring. Cheers. SM
I’ve been hearing a lot of good things about these jackets! Two questions:
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What are the dry weights of the jackets you tested? Breathability is only one part of the equation when it comes to how sweaty your shirt gets. If the Gore-tex jacket was made of a heavier fabric, that could have contributed to more heat retention (and, thus, sweating).
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Did either jacket have pit zips? How was the breathability compared to a jacket with open pit zips?
How is the durability (waterproofness) doing if you have used it for a full year? I suppose it depends a lot on your actual time and type of usage though…
Polartec Neo was/is a fantastic fabric in terms of waterproofness, breathability, comfort… (many characteristics are similar to how Futurelite is being described) but after about a year of very hard use my jacket drastically failed at high wear points. Goretex is much more durable, but depending on the variant, has certain issues (e.g., sweat/oils affecting the uncoated Gore Pro). Futurelite is another membrane (with a different type of construction). It certainly seems to perform great – but how does it hold up?
DWR is, of course, another story. All companies have been struggling with the environmentally-motivated change to a poorer DWR. It sounds like Futurelite is a membrane laminated to a face fabric. So, I assume it will have the same problems with DWR after a bunch of washes/use. Is that correct? It would be very neat if the membrane removed that problem.
Would be great to see a Futurelight comparison to the more breathable shells out there that it actually competes with, as opposed to a Gore-Tex Pro shell that pretty much isn’t breathable at all in comparison. Neoshell, Gore Tex C Knit/Active, E-Vent, etc, would all be better comparisons.
What’s the durability been like on these garments?
The scientific method is alive and well! If only all gear reviews provided dehydration data
I would also appreciate a comparable test with Dynafits own Dynashell properties. So far my favorite was and is Gore Windstopper in terms of breathability as soon as I accepted a membrane for the given application. And I would never ever trade in ventings for weight saving
Wouldn’t the garment color (almost white vs. blank) invalidate the comparison during a sunny day at altitude?
yo, another idea: repeat the test but weigh yourself after. this is a pretty good gauge of fluid loss.
also—is the future light stuff air permeable?
Here is the problem with this test. I have done testing of Neoshell, AscentShell and Futurelight. All are electrospun PU membranes. There are two test numbers that matter for each: Hydrostatic head measures water resistance. MVTR measures vapor transmission. Here is what each does, respectively for HH and MVTR: Neoshell-16170, 2940; AscentShell-16170, 3060; FutureLight-16416, 2780. All of these fabrics are very similar in performance. Now, consider Gore Pro and Gore Pro Shell. Gore Pro-30000+, 2869, Gore Pro Shell-30000+, 1800. If you had done your test in any of the electrospun fabrics, you base layer would have been about equally wet. If you did you test in Gore Pro, you would be equally wet. If you do the test in Gore Pro Shell, you will get the results that you recorded. Gore Pro Shell is pretty crappy. Gore Pro is a big improvement. Where Gore shines is in its water resistance. If you sit in a puddle with the the microspun garments, you may get a wet ass. If you do the same with Gore Pro, you won’t. I enjoyed Neoshell for many years. However, I had a lot of problems with leakage in my pants from sliding on snow. Now my pants are Gore Pro.
Here is the answer to Rob’s question. Air permeability is measured in CFM/Ft2. Here are the numbers for the 3 electrospun membranes: Neoshell-1.06; AscentShell-1.23; Futurelight-1.1. Gore Pro: <.43. The standard for this is equivalent to a 32 MPH wind. As they claim, the 3 electrospun membranes have more permeability than most WPB membranes. However, to get any air coming through the garment, you will need to wear it in a class V hurricane.
Hi Stephen. That’s great information–thanks! Two question: 1) Does the air temperature or relative humidity influence these results? If so, does one of another membrane perform better in cold dry conditions, or warm and wet conditions, and so on. 2) Is there anything about the way these membranes are integrated with face fabrics or backing that significantly alters these results? For example (just to take the new kid on the block) does NF do anything with Futurelight that is unique in this regard to clothing from other companies? Thanks again. Bruno.
Temperature and humidity influence vapor transmission for all WPB membranes for a couple of reasons. 1) Vapor is driven across the membrane by vapor pressure differential. Vapor pressure pressure differential is a function of temperature and humidity on both sides of the membrane. Most MVTR test standards will test to a specific vapor pressure differential. The differential is generally not specified but results from the specified test conditions. 2) Hydrophillic polyurethane membranes increase vapor transfer as humidity concentration on the inside of the membrane increases. These membranes reduce vapor transfer as temperature decreases. Examples of this type membrane are bicomponent membranes such as Gore Pro Shell or PU coatings such as Sympatex. The second part of your question is more complicated. Each membrane type will have trade-offs. Concerning your second question: I think the magic is primarily in the membrane, but the face and inner fabric will have their own vapor transmission resistance as well. NF makes several different variations of Futurelight garments with different fabric deniers. I have only tested one, so I can’t say if the others have significant performance differences. Based on my tests of similar products from three different manufacturers that produced similar results, I suspect not. However, NF does claim they can alter the membrane characteristics to achieve different performance characteristics.
I shelved my build of a breath-ability test rig. Robotic solutions are no match for Doug’s metabolism! Lou
If you need a jacket for hiking in dry heat, it’s great! Just don’t wear it in the rain or expect it to be durable!
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