For years I have been arguing that modern waterproof/breathable fabrics — including every version of Gore-Tex and eVent, plus proprietary fabrics like Patagonia’s H2No, Marmot’s NanoPro, Mountain Hardwear’s Dry.Q, and dozens of others — are technologically flawed. (Read this, this, maybe this, and The Ultimate Hiker’s Gear Guide.)
Relative to the marketing hype, these fabrics earn a giant FAIL in their real-world performance. In my experience, which is extensive and which includes long-term wear (in contrast to most “reviews”), waterproof/breathable shells have failed to keep me dry from precip (outside), perspiration (inside), or both.
Why? Three causes:
1. Ambient humidity
If humidity inside the garment is greater than outside, moisture from inside the fabric will pass through to the outside, where it can evaporate. But ambient humidity is often very high during heavy precip, especially in the East. As a result, the moisture inside the garment does not get “pulled” towards the outside, and perspiration builds up. The result: You’re wet from the inside.
2. Not breathable enough
Technically, WP/B fabrics are breathable, i.e. moisture can pass through the fabric. But the level of breathability is inadequate to keep up with moderate- or high-aerobic activity, even when ambient humidity is very low. I’m surprised that fabric manufacturers have never been sued for false marketing claims, given how they describe the fabrics as “extremely breathable” and post photos of a runner in a WP/B shell.
3. Durable water repellent (DWR) failure
When new, the DWR treatment causes water to “bead” on the face fabric. Unfortunately, it quickly degrades due to abrasion, dirt, body oils, and other contaminants, and after short-term use the exterior fabric begins to “wet out,” or become saturated with water. At this point, humidity “outside” the fabric is 100 percent, and moisture will begin to move through the fabric to the inside — the reverse direction that is desired. The result: You’re wet from the outside.
The next generation of WP/B fabrics
I think we’re about to see a new generation of WP/B fabrics. With existing fabrics, a membrane made of expanded polytetrafluoroethylene (aka e-PTFE, or Teflon) is sandwiched between an exterior face fabric treated with DWR and typically some type of interior mesh or other surface, or nothing. Fabrics are often described as 3-layer, 2.5-layer, or 2-layer.
Columbia was the first to market with a new generation of WP/B fabric, launching OutDry Extreme earlier this year. Yesterday I read in Gear Junkie that a new version of Gore-Tex Active has been released, currently only available in one jacket from The North Face. This release sounds very unconventional (a 12-week product cycle, versus the normal 18 or 24 months) and I can’t help but wonder if Gore panicked when it learned of Outdry Extreme. And I suspect these new fabrics are about to become more widespread, since I’ve seen several unbranded fabric swatches floating around the Sierra Designs office.
With these new fabrics, the DWR-treated face fabric has been eliminated and the membrane is now on the outside; some type of interior liner remains. The fabrics look and feel rubbery, like the rain slicker that you might have worn as a kid.
Are these fabrics revolutionary?
Without long-term first-hand experience, I cannot yet personally say whether these next-gen fabrics are a true improvement over existing products. Hey, Columbia and Gore-Tex: I’d love to get a jacket to test!
I also have not seen any extensive long-term reviews. Gear Junkie and Indefinitely Wild were seeded with early product, but results of more rigorous testing has not yet been released.
Certainly, the elimination of the DWR face fabric is an improvement, since this is the Achilles heel of modern WP/B fabrics, especially for long-term use. But it remains to be seen whether these fabrics maintain a “permanently beading” surface, or whether the exterior membrane somehow begins to fail.
If the former, then absolutely these fabrics represent a step forward. If the latter, there will be no change to real-world performance, but it will be repackaged in new fabric construction and in a new marketing campaign.
I’m less concerned with fabric breathability — it’s not the primary problem. Early indications are that the fabrics are more breathable, but not a worthy substitute for, say, a wind shirt or fleece.