Patagonia Airshed Pullover Review

Jarred-thanks for the insight. I don’t own a wind shirt but I hear many people raving about the versatility, just trying to figure out where it would fit in.

Jarred- I’m using a Patagonia Level 4 windshirt for hunting- heavier denier/sturdier, not sure on cfm, but it’s encapsulated (vs a DWR) so pretty moisture resistant and stays that way

Mike

Mike,

Got it – thank you. Hard enough to find these in a medium that I gave up when looking for one last year.

Brad,

As a concrete point of data I used my Alpine Start on 1.5 hour run yesterday morning @ 9:15 minute miles. 36 degrees, before sunrise, 6mph wind, 48% humidity. Air felt noticeably nippy with a slight frost on the ground. I consider myself warm while moving. I wore nothing underneath the Alpine Start and was comfortable on the arms and torso – I did not need to vent at any point. With an Echo underneath I would have certainly needed to vent at some point.

Jarred-thanks. It’s starting to make sense. Your Alpine Start at 35cfm, would require less base layer than the Airshed-50-60cfm to perform equally.  In your scenario a thin synthetic t-shirt under the Airshed may have yielded similar results?

Naw, the Alpine Start is higher CFM than that. Perhaps ~60.

https://backpackinglight.com/forums/topic/107471/

There are other sources for that. A little digging will provide CFM values for various peices although as consumers we are still largely left in the dark. Experientially I can say with confidence (having used both a Squamish and an Airshed) that the Alpine Start has a higher CFM than the Squamish (~50 I’m close but not exact on that number) and is similar to the Airshed. That is why I was using it as a point of reference in this discussion.

CFM values (again from a consumer standpoint) are vague. You would do best to consider them in increments of 10. Thus a Squamish at ~50 is slightly less air permeable than an Airshed/Alpine Start but significantly higher than a Tachyon (~20) or a current Houdini (~5). However the difference between, for example, 30-35 is not particularly significant. I hope this is good information.

Edit: I also do not mean to be monolithic. Just trying to paint as clear as picture as I can. I’m sure others could take umbrage with personal appraisal and in that there is more that I could learn.

Jarred-thank you. Very helpful. It is appreciated.

@Ryan:

“Perhaps asking a wind shirt to perform the function of a rain jacket is asking too much.”

Sure, but a wind shirt can be better than a rain jacket in light rain.

I live on the East coast. Drizzle and humidity are facts of life here. I find most rain gear miserable for hiking until the temperatures are low. A few degrees lower and the rain turns to snow, where a wind shell again wins.

(Of course, in heavy rain, then the real rain gear comes out. Or around camp/town.)

Agreed that breathability is perhaps the most important factor for wind garments. A wind shirt does not have to block ALL wind; it only has to tone it down a little.

The key is in finding the right balance between breathability and perhaps a little bit of water resistance for a given use case. This is where BPL has done a better job than most other sources of describing that balance and in finding a few garments that do the job.

Please keep up the good work. Specifically, I’d like to know CFM, HH, and MVTR for all (good) wind and rain garments.

I’d like to know CFM, HH, and MVTR for all (good) wind and rain garments.

Ha~! Everybody would like to know these measurements. Problem is, manufacturers change their lineup so frequently, by the time the testing is done, the figures will be practically out of date. Not to mention that amount of work and money it would take to acquire samples and then test them all.

In an ideal world, the manufacturers would just publish all that information themselves.

I was referring to future reviews here on BPL.

Just suggesting that a part of the review could include sending the garment to one of the member-owned labs for CFM, HH, and MVTR testing.

(Assuming, of course, that the scientist involved is interested in such testing.)

Hi Bill:

You mean something like this:

I have not tested any windshirts since 2021, because I stopped using them and started concentrating on WPBs.  However, if someone is curious about a windshirt and wants to send it for testing, PM me.  Note that my air permeability and water resistance numbers will be consistent with the industry standards.  My MVTR is not.  You can convert my MVTR values, roughly, to JSI 1099, B1. the standard that is typically used by manufacturers with the following formula: Perm Kettle MVTR=(.0308*(JSI 1099 B1 MVTR))+941.61

hmm- here’s what Black Diamond said concerning the Alpine Start, this was from 2014, maybe they changed it????

I received this response from Black Diamond:

Thanks for getting in touch with us. The jacket is 40 CFM (cubic feet per minute) which is technically 40 CFM/M2 (cubic feet per minute per meter squared) but the industry simply refers to this as CFM. This is testing done by Schoeller and tested by BD. It is a stretch fabric and should increase the CFM slightly when stretched. 

The hydrostatic head is approx 500 mm. It is treated with Nanosphere but does not have any coating that is generally required to get higher hydrostatic performance.

Kim Hall | Black Diamond Equipment

@crashedagain: Yes, that’s exactly what I was suggesting. Awesome! (and thanks)

Just my $0.02: WPB’s are interesting and it was great when you jumped on the new Columbia Outdry Ex Mesh. But windshirts work better for me in more kinds of weather. Part of that could be due to East vs West climate differences. Your chart above covers most of the usual suspects, which is excellent.

@MikeM: Wow, great report from BD. Is Nanosphere permanent, rather than DWR?

@crashedagain: While we are reconciling numbers, your CFM measurement for the Houdini is almost an order of magnitude lower than other test reports in the past. Do you know whether that is due to yet another change in fabric? Or just differences in the way various labs do testing?

Who knows.  Somewhere, I have data on tests I did of several different years of Alpine Start jackets and they all had similar results, as I recall, but I don’t know where those results are hidden away. I did conclude that the fabric has been consistent over the years. It is possible, from the information in your post that they stretched it during testing air permeability testing.  This is not something I would have done.  As for the hydrostatic head, I tested well-used jackets sent to me by a BPL member.  They could easily have lower HH than a new, never used piece of fabric.

Mike,

I also wrote BD about the Alpine Start, twice, and got similar numbers from them. I would trust Stephen’s numbers. At one point, he verified his air permeability measurements against those from two independent labs and got good agreement. Company spec is one thing, lab tests of actual product another.

My experience (which is worth far less than lab results) would agree with Stephen’s 13.2 CFM figure. From my point of view, that’s a good thing. CFM above 15-20 lets in too much wind to keep one warm, especially in winter. I think relatively low CFM to protect from the wind, combined with high MVTR to allow water vapor to escape, is where it’s at with wind shirts. High HH is a bonus. Windshirts that have all three of these qualities are the bee’s knees, and the BD Alpine Start is one of the few that does.

I think there is a place for high-CFM windshirts, and I have a couple, but I don’t use them that much. I’ve tried using high-CFM as a bug shirt, which works great against bugs, but when the bugs are out it’s usually too warm even for 60 CFM. I prefer lower-CFM shirts, and if I need more ventilation, I open the zip.

I also think that using Polartec Alpha with low/moderate-CFM shirts works extremely well. The Alpha is so ridiculously permeable that you want to block all or most of the wind, but that permeability also allows for extremely effective venting (of moisture, or heat, or both) by opening a window (a zipper).

I have a 2017 Arcteryx Squamish, which Stephen tested to have about the same MVTR as an Alpine Start (~3500), but three times the air permeability (~40 vs ~13). I wear the Squamish quite a bit, as it’s my best-fitting windshirt, but if I’m going to be out all day or for multiple days, I never take it. I do not think it breathes better than the Alpine Start (despite its high air permeability), but it definitely lets far more wind through (due to its high air permeability).

Hi Bill:

You will see some variance, sometimes substantial, between some of my test results and some of the information previously published on BPL.  As a result, I paid to have 3rd party testing done to investigate these issues.  My results are in good agreement with all the independent testing I had done.  I had my 2018 Houdini, listed above, tested by Frazier Instruments.  They manufacture the most widely used air permeability test instruments.  They got .32 vs my .65.  .65 is about as low as I can go. Patagonia regards anything lower than 5 CFM as impermeable.  I would agree with that.  I have never succeeded in obtaining any old Houdini jackets for testing.  If you have any with the claimed higher permeability, I would like to test it. Also, I received and responded to your PM.

Bill, Nanosphere is a very durable DWR, but it’s not permanent, despite marketing language from Schoeller that might suggest it is. Abrasion is the bane of DWR, including Nanosphere. However,  I found Nanosphere to be the most effective DWR that I’ve tried, and possibly also the most durable.

I once did some shower testing comparing a brand new Alpine Start against two other wind shirts with slightly higher water-resistance (hydrostatic head, HH). The Alpine Start actually let a little mist through in the shower, but the fabric did not wet out. It was bone dry after allowing a little mist to explode through the pores in the fabric. The other two didn’t let water through, but wet out very quickly. This was an example of how water resistance and water repellency are not tightly correlated. The former is a function of the fabric itself (pore size, weave density, etc.) and the latter a function of the DWR chemical treatment and how it interacts with the surface of the fabric.

For a long time, I tried to make wind shirts with good DWR and high hydrostatic head work as raingear in light and medium rain. This can work, but the limiting factor is the DWR. I’ve never found a DWR that lasts long enough to prevent the fabric from wetting out. Brand new it can be pretty great. But once some abrasion from pack straps and brush have worked on the fabric some, it will start to wet out in those areas. Once wet out, water from the saturated fabric will start to infiltrate your inner layers. For done in a day activities, this can still be OK, but it sucks pretty bad if you’re spending the night outside in the cold.

BTW, Black Diamond stopped using Nanosphere a couple years ago. They now use a wax-based DWR called Ecorepel that is far less effective and durable. I suspect the reason for that is that Nanosphere in its most recent iterations was a fluorocarbon-based treatment. And those chemicals are in disfavor. The original Nanosphere was actually silicone-based. It worked well, but it did not repel oil, so body and plant oils could foul the surface treatment and render it useless. This is the same problem that Epic by Nextec, another silicone-based DWR, faced.

Stephen: OK, that’s all we can ask. Thank you. Sorry, I do not have an older Houdini. I do have a PCU L4 from Patagonia that I could send.

Stumphges: Right. When BD said, “treated… but not coated”, I envisioned something like EPIC encapsulation: A treatment that happens when the fabric is made.Thanks for clarifying.

Too bad about the Ecorepel.

It’s interesting how everyone reacts differently. I have always preferred wind shells in light rain, regardless of DWR. Somehow I find slightly-damp-from rain to be more acceptable than slightly-damp-from-sweat-that-cannot-escape-a-rain-jacket. If “wet is wet”, then maybe it’s more about cooling? In any case, the wind shell tends to dry faster than a rain shell when the rain stops.

“It’s interesting how everyone reacts differently. I have always preferred wind shells in light rain, regardless of DWR. Somehow I find slightly-damp-from rain to be more acceptable than slightly-damp-from-sweat-that-cannot-escape-a-rain-jacket. If “wet is wet”, then maybe it’s more about cooling? In any case, the wind shell tends to dry faster than a rain shell when the rain stops.”

Oh, I much prefer a windshell. That’s why I worked that strategy for five or six years. But it just doesn’t work unless the DWR is pristine and the windshell has top-10% HH. If damp from outside equals damp from inside, sure, that is the use case for windshell over rain shell in light or medium rain. But all it takes is for the rain to get a little heavier, or for your DWR to give it up during a long hike or trip, and the strategy fails. And when that happens, wet from cold rain is conspicuously, dangerously worse than damp from warm sweat.  And then you have to dry those layers, or put them on in morning. I still do it on day hikes, but would not rely on it for backpacking, and DWR fragility is the biggest reason.

I don’t see heavier rain as failure for a wind shell; I just see it as time to put on the poncho.

+1 for BB

I do have a PCU L4 from Patagonia that I could send.

I’d be interested to see that :)

Looking at all three components, it does seem the Alpine Start does pretty well comparatively :)

The windshirt/fleece/base layer can be worn in any combination and having the windshirt breathable extends the versatility of the whole package.

…

A few degrees lower and the rain turns to snow, where a wind shell again wins.

That is my approach for cross country skiing. While going up hill I sweat a lot. I ski in the Northwest, where temperatures are often right around freezing. Often fleece is enough, but it can get too damp. A windshirt helps quite a bit. As I gain altitude I usually get into colder, dryer temperature. The wind shirt may be soaked. Mainly it prevented the fleece from getting soaked (with either my sweat or the rain/snow mix). If I’m still skiing, I don’t need the wind shirt, and can set it aside (although it usually isn’t that wet). If I’m stopped, I put on my down jacket. Going downhill I just wear the down. It might rain on me at the bottom, but by then I’m close to the car. If I was camping, I would probably carry a rain jacket as well (to put over the down jacket when the temperatures drop, to protect it). Instead I just let the jacket dry out at home.

Hi Mike:

Thank you for the offer.  One is already on the way.  I will post the test results.

Hi Mike:

Thank you for the offer.  One is already on the way.  I will post the test results.

That’s great Stephen- thanks!

Regarding Patagonia Houdini–there was an in depth discussion about this windshirt some years back on this forum.  If I’m remembering correctly, the Houdini pre 2012 had a measured (by Nisley) CFM of around 30 to 35 which he considered the optimal CFM range for balancing moisture movement against wind protection whilst backpacking on hilly, up and down type terrain/trails.

Pre 2012, it also had an EPIC like, silicone based DWR.  Around 2012, both the weave and DWR were changed and the Houdini became much less air porous (“breathable”).  I haven’t looked for any links yet, but I’m sure if you did a search of 2012 Houdini Nisley or the like, something would eventually come up.

Btw, the way to refresh silicone DWR is a combo of the following: Hot water combined with plenty of agitation and most importantly, a high pH cleanser of some kind. This could be washing soda or the like.  The high pH (needs to be at least 10 pH) cleanser helps to emulsify and break up any surface oils that may be impairing its DWR function.

This, btw, is perfectly doable on a backpacking trip.  Make a fire, once cooled, put some of the ash in water, let it sit for awhile, strain off the clear water off the top. You now have a form of lye–a high pH cleanser that will emulsify oils/fats.  Obviously be careful with this and handling (depending on how concentrated you made it, it can chemically burn the skin or at the very least strip the oils from the skin).  If you have one of those collapsible, portable, relatively light kitchen sinks, you can heat up the water and throw the windshirt in there and swish it around, and then rinse it well with regular water.  It would be easier to do all this at home, but it can technically be done in backcountry if really needed.  I could only see this as necessary on a longer trip–particularly with a lot of bushwhacking.

The good thing about silicone coating DWR’s is that they tend to be much thicker than other DWR’s and for that reason primarily, tend to be much more durable and longer lasting. But over time with use, will need to be refreshed in the above manner.  Occasionally spraying with a silicone spray after a deep cleanse, can also be helpful after a lot of time. The silicone should readily bond with the silicone coating. It is different than spraying silicone on an uncoated fabric–in that case, the silicone DWR will come off quite fast and easily in comparison to spraying on an already silicone coated fabric.  The silicone spray will NOT increase the HH at all though.  It is just too thin of a coating.  You could do the old thinned silicone caulk trick to do that, but you would have to have the ratio of thinner/solvent to silicone down perfect to not overly impede air porosity.  Not likely without a lot of testing and trial and error.