Windshirt Question

[Scott Hayden]

I had not listed that in my original findings as the price was a bit higher than I wanted to pay. Most of the stuff that I was looking at was clearance. The 140 price was twice the Houdini, which should be arriving Wed from BackCountry, and the houdini was twice the price of the montane. I am hoping the Houdini will fill my needs. I may not be a strict on my requirements that others. Nor do I have the experience with all the fabrics and tests. Nice thing about this place, lots of experience here.

[Brendan Swihart]

I've been using a Squamish after losing my Houdini last spring. I found it on clearance and price was on par with other similar windshirts. Fit is great (although it could be slightly longer), DWR is excellent, breathability seems to be better than the Houdini. Overall I like it quite a bit.

[David Chenault]

I agree with Paul. The cutting edge of windshirts is trying to make something as light and almost as weather resistant as Quantum (for example), but breathes better. It's easy to make a calendered SUL fabric which looks good on paper but breathes like crap (Tachyon, Ghost Wisperer, Quantum GL all fit here). Personally, I'm willing to carry 6-7 oz v. 3-4 if I can bust brush and not worry about snags.

[Justin Baker]

"Personally, I'm willing to carry 6-7 oz v. 3-4 if I can bust brush and not worry about snags."

+1
I've found a few thrift store windshirts that were a bit heavier, but the fabric was pretty rugged and it breathed well.

[Paul Hatfield]

Well if I am going to carry something that weighs 5 ounces and blocks the wind, but isn't ultra-breathable, then I'm probably going to carry my O2 Rainwear rainjacket, which blocks the wind, is waterproof in sustained rain, and is quite comfortable next to the skin. It's not stylish and not for bushwacking, but for rainwear, it "breathes" quite well.

[hwc 1954]

Quote:

Well if I am going to carry something that weighs 5 ounces and blocks the wind, but isn't ultra-breathable, then I'm probably going to carry my O2 Rainwear rainjacket, which blocks the wind, is waterproof in sustained rain, and is quite comfortable next to the skin.

I carry both. A 6 ounce Marmot Essence rain jacket — ultralight waterproof "breathable" and a 5 ounce Trail Wind Hoody. Nobody would seriously compare the breathability of the two. I think it's an exaggeration to say that any unlined/unlaminated 5 ounce wind jacket will be as wind proof or non-breathable as a PU laminated ultralight rain jacket. I would certainly never put on the rain jacket instead of the wind hoody unless it were raining/snowing and/or I were freezing cold and trying desperately to warm up. The laminated rainjackets are ultra-nonbreathable.

[James holden]

i own and use the trail wind …

IMO it is not very breathable at all … it needs those perforated holes below the armpits to keep it breathing barely adequately

there plenty of other shirts that are more breathable … a simple breath test will tell you that very quickly

;)

[Paul Hatfield]

"The MEC RD Windshell Jacket has a CFM rating of 7.
MEC does not carry any high rated CFM jackets."

– MEC Service Centre

[hwc 1954]

I'm just having a hard time comprehending the big deal. I mean, I understand how miserable it is to have to wear a rain jacket zipped up because it's raining. But, we aren't talking about rain jackets. We are talking about a very thin wind jacket. I only put mine on because I feel too cold without it (from some combination of wind and temperature). The only reason I put it on is because I want to be warmer — specifically because I want the wind to stop cooling me down as much.

If I then get too hot, I either unzip it or push the sleeves up. Or, take it off.

I have other shirts that are nearly 100% breathable. For example, virtually any long sleeve tech shirt will provide a little additional warmth with virtually no wind protection. Many of my long sleeve shirts have large mesh panels with terrific breathability.

I don't think you want a wind jacket with 0 CFM air flow, but the zipper is a wonderful thing!

But, there's any easy solution. Just run any of these jackets through the wash a couple dozen times to get rid of the DWR finish. I suspect that will make them quite porous.

[Richard Nisley]

hwc,

To understand how to use a wind shirt properly you either need a lot of experience or an understanding of the related physiology and physics concepts. I can't help with the experience option but, I can with the other option.

"We are talking about a very thin wind jacket"

-Thinness is related to weight but, it has NO correlation with the primary functions of a windshirt. The primary function is to maintain an optimal micro-climate for a broad range of conditions.

"I only put mine on because I want to be warmer"

-In the typical UL backpacking environments the optimal micro-climate for comfort can change quickly and frequently. For example: in the shade; out of the shade; sheltered from wind; not sheltered from wind; walking on flat ground at 3 MET; going up a hill at 7 MET; sun behind clouds; sun unobstructed; ground hard; ground sandy; ground covered in sun cupped snow; radiation from a rock out cropping, no radiation from rocks, etc..; and etc.

"If I then get too hot, I either unzip it or push the sleeves up. Or, take it off."

-You have defined your way, the most inefficient, to deal with the micro-climate variability. The problems with that approach are twofold. First, taking a jacket on and off to regulate temperature, while carrying a backpack, is the most time and energy inefficient scenario possible. Second, the scholarly research has shown aperture ventilation (unzip, zip, push up sleeves, open pit zips, etc.) achieves less reduction in moisture transport resistance than an appropriately air permeable fabric.

"I have other shirts that are nearly 100% breathable. For example, virtually any long sleeve tech shirt will provide a little additional warmth with virtually no wind protection. Many of my long sleeve shirts have large mesh panels with terrific breathability."

-100% breathability is also known as the garment air permeability required to never become an impediment to sustained physical activity. That value is 400 CFM; it is typically only found in a loose weave T-shirt. Most conventionally woven technical shirts have an air permeability of approximately 100 – 150 CFM.

The scholarly research shows that for a base layer plus windshirt ensemble, as the air permeability goes up, the water vapor moisture transport also goes up approximately linearly to about 35 CFM. After that, the ensemble's moisture resistance elements found in the base layer, the base/windshirt air gap, and the windshirts’ boundary layer predominate. Further increases in the windshirt's fabric air permeability have a negligible benefit in the ensemble's system performance. Since a more breathable windshirt allows more forced convection (wind) in, most people intuitively believe they are improving their moisture expulsion rate; they are not.

"… there's any easy solution. Just run any of these jackets through the wash a couple dozen times to get rid of the DWR finish. I suspect that will make them quite porous"

-Any commercial DWR finish, applied according to the manufactures directions, has zero effect on the breathability of a garment. Washing doesn't change the weave and so the air permeability stays the same.

-UL backpacking is the only common sport that produces 7 MET activity and its attendant heat on a sustainable basis. It is the case in which most windshirt manufactures don't specifically target. Those that do, size the windshirt to create an optimal gap between it and the base layer of 3/8" – 1/2" adds .6 clo of warmth for free. They provide a weave that passes approximately 35 CFM because this the level that provides the most exports of body moisture with the least vulnerability to forced convection heat loss. Those windshirts optimize for UL backpacking also have either an EPIC thread coating for garment life time DWR or a fluorocarbon coating for moderate life DWR.

A windshirt designed for UL backpacking will best maintain a thermal neutral body temperature without requiring the wearer to constantly diddle with it. It will also yield a HH value in the range of .43 – .75 PSI (300 – 527 mm H2O HH).

In summary, a properly designed windshirt for UL backpacking adds warmth by the addition of .6 clo in the base-layer-to-windshirt air gap plus another .6 clo from the windshirt's boundary layer (this will vary with wind speed). When your body goes above its thermo-neutral point, you start producing sensible perspiration. If the air permeability allows the moisture to evaporate and pass through to the outside environment, the latent heat of evaporation cools your body back to the thermo-neutral point. If the air permeability is not sufficient to pass the amount of moisture being produced to the outside environment, the water stays on your body. Once approximately 20% of your body is wet, you have a feeling of discomfort. This is primarily sensed by the increased clothing friction. To put the difference in ability to pass moisture out in perspective, a Frog Togg or equivalent garment will pass .17 CFM and a pre-2013 Houdini will pass 35 CFM. Hence, a dramatic difference in the ability to automatically cool your body as required by different brief micro climates without any diddling.

[Woubeir (from Europe)]

Interesting. How long did you have that Houdini ?
Regarding the Squamish, currently it has a claimed CFM of ± 7 while Richard Nisley measured a CFM of ± 100 which was more or less confirmed by the Arc'teryx Customer Service as one of those Squamishes using their Gossamera-fabric while it was still uncoated. However, I got from them another answer namely that it always had a coating. So very conflicting info.

[Richard Nisley]

I tested a US distributed 2007 Black Acteryx Squamish Windshell (Gossamera without the air permeable PU coating) at 100.59 CFM. I noted the 2013 Arcteryx specification for Gossamera was 7 CFM. I exchanged emails with Arcteryx Customer Service and the following is a summary of that email exchange:

On May 27, 2013, at 2:20 PM, "ARC'TERYX SERVICE" wrote:

Hi Richard,

The PU coating to the Gossamera fabric was introduced in 2009. 2008 and before don't have the PU coating.

Best Regards,

Arc'teryx Service Team – Jerome
ARC'TERYX Equipment Inc.
http://www.arcteryx.com

---

Summary: Service Forms: ASKSPCL Customer No 169704
Subject:RE: Service Request: Ask a Specialist (RefNo. 1087978)
Name:Richard Nisley
Email:

Message:Jerome,

Thank you for your prompt reply. The specs for the current Gossamera fabric state that it has an air permeable PU coating. There is no air permeable PU coating on the 2007 Squamish that I own. What years was an air permeable PU coating not applied to the Gossamera fabric and what years was it applied?

Thank you,
Richard

[Woubeir (from Europe)]

I know Richard but here is what I got from them on 29/05/2013:

"Good morning Tom,

thanks for contacting us

Regarding the Squamish hoody, the Gossamera fabric has always had a PU coating and DWR finish. The only difference between the Gossamera and Luminara is the weight: Gossamera is 30D mechanical stretch nylon ripstop 52g/m2 and the Luminara is 20D mechanical stretch nylon ripstop 44g/m2.

We are sorry to not be able to provide the CFM values, as we do not have them available for the Luminara, but they are very similar and hard to notice their difference as individuals

Best Regards,

Xavier

Arc'teryx

arcteryx.com"

Why those conflicting answers ? Possibly because Arc'teryx only started stating in their tech manual from spring 2009 that Gossamera had/got a coating. Other specifications like e.g. weight were exactly the same. Now, does Arc'teryx only specify the weight of the raw fabric or including coating ?

[Dan @ Durston Gear]

"The MEC RD Windshell Jacket has a CFM rating of 7.
MEC does not carry any high rated CFM jackets."

From ample personal experience, the RD Windshell is highly breathable. It's nothing like the pseudo-plastic bag windshirts (ie. Montbell). Unless you're looking for a super DWR windshell to attempt to wear during light rains, the RD is great. Compared to the Houdini, the RD is easily more durable and breathable.

[hwc 1954]

All a very complicated way of saying that you get and sweat when carrying a backpack, especially uphill. I think that's something everyone who has hiked around here (White Mountains) has figured out pretty quickly.

When I'm hot and starting to sweat, the very simple solution is to NOT put on a wind jacket, but rather to stay in a lightweight wicking baselayer — either long sleeve or short sleeve depending on the temps I expect to encounter.

It seems that now that Houdini and Squamish have "ruined" their products, there is no wind jacket that passes such a stringent definition of acceptable air permeability. This is probably because a wind jacket with such permeability would no longer be very effective at its main design criteria: blocking the wind.

I have found that hybrid jackets can help — more wind resistant materials on the torso in conjunction with more breathable fabrics on the back, sides, and arms; however, most of these weigh more than 5 ounces.

[Woubeir (from Europe)]

Which Houdini ? The 2013-model or an earlier model ?

[Timothy Epp]

You could also look at the North Face Verto Jacket. I own that one and it does provide a measure of wind and rain resistance and only weighs 3oz. I got last year's on sale for 75.00

[Ryan Smith]

"From ample personal experience, the RD Windshell is highly breathable. It's nothing like the pseudo-plastic bag windshirts (ie. Montbell). Unless you're looking for a super DWR windshell to attempt to wear during light rains, the RD is great. Compared to the Houdini, the RD is easily more durable and breathable."

I think Richard tested the air permeability of the Montbell Tachyon and came to a 9 CFM rating. So the RD might be less breathable actually. I might be remembering incorrectly here so take this with a grain of salt.

I am thinking there are many, many factors that will affect how breathable we perceive a garment to be. Maybe that's why the tests and actual experience can differ so wildly on wind shirts and rain jackets. Fit of the garment, exertion levels, actual CFM rating, etc. Dunno. Interesting stuff.

Ryan

[James holden]

the RD windshells of my partners that ive tried and the ones ive played around with at MEC are quite breathable IMO

much more so that my trail wind

as the the MB … if its the same fabric as the EXL puffies … well that fabric isnt "breathable" at all …

as to the "high CFM" thing … i suspect that most "normal" people these days use their windshells as a semi-static layer or just walking around the park, so a less "breathable" windshell makes sense from a marketing perspective

god forbid you get reviews on backcountry, REI or amazon saying "this $$$$ windbreaker SUCKS, it doesnt block the wind !!!"

and to be quite honest, even among people who use it for higher exertion, most dont think that sweating is such a big deal anyways … you can always walk into a warm building to dry off

if you want "guaranteed" breathability get a thin non-membrane softshell … theyll be more durable (and heavier) to boot

;)

[Dale Wambaugh]

I haven't seen the Montane windshirts discussed much. They are more difficult to find in the US, but should be included.

I'm a little puzzled by the metric fabric specs: Pertex rates the air permeability of their Quantum GL and Microlight fabrics at 1.0cc max. The conversion calculators I found show 1cc/s = .002 cfm. It seems that I'm missing something terribly, the specs are wrong, or the fabric doesn't breathe much at all.

I got an older Patagonia Nine Trails jacket and have tried it on a few walks. It has a slimmer cut, especially in the arms and no hood. That aside, it has a large breathable back panel and the fabric is the same as the older Houdini from what I can tell. I would assume that the new Nine Trails uses the same less breathable fabric as the newer Houdini, but you still get the ventilation from that back panel. Perhaps this is a work around?

I was surprised to hear that opening a front zipper isn't a gain over 35cfm fabric. I guess that is due to air trapped in around the shoulders and back, particularly with a pack on? I can grasp that my base layer and shell work in concert to move excess moisture away from my skin, but it seems that opening the front zip should make up for a lot of fabric porosity. I'm using a 35cfm garment to start with.

My own technique to managing a windshirt (or rain jacket) is to start opening zippers and cuffs before taking it off. With the windshirt, I might even tuck some of the back fabric up behind my mid back. It's all in adjustment to terrain changes and exertion, forest cover, sun/wind /precipitation changes and additional warmth on rest stops. If I know I will be stopping for a break and I'll be getting the windshirt back out, it seems easier to vent some vs stopping and swapping everything around.

Perhaps a mini wind poncho design would be good for hiking, where you could wear your pack straps under and flip a zippered front panel back over your head and pack when you don't need the extra layer?

[Paul Hatfield]

Richard wrote in a different thread: "I have not tested a Montbell Tachyon but, I have tested the SAME APPARENT Montbell 7 denier ballistic rip stop used in their EX Light. It tested 9.72 CFM."

[James holden]

opening the main zipper makes a huge difference IMO

the problem is that you cant always do that … it defeats the purpose of a windshirt, which of course is to reduce the chilling effects of the wind

also it doesnt help the arms which, for me, tend to sweat quite a bit

theres no such thing as a free lunch … for climbing a less "breathable" windshirt can be useful as technical climbing (not easy slogs) are a stop and go activities with belays … youll feed the wind through very breathable material … on the other hand with the approach to the climb you may well sweat like a pig if you wear a less breathable windshirt

the way around it i find is to wear very little under the windshirt/softshell (or not wear it at all) when slogging uphill .. and put on a light fleece under (or light synth over it) when doing technical climbing

for hiking one can do something similar with a light fleece vest on descents or flat ground if its chilly

unless you are in constant motion and basically never stopping for more than a few minutes … its quite hard to find a single layering setup that fits all scenarios …

runners and cyclist can do it … but they cant stop for too long or they get cold fast

;)

[Richard Nisley]

Dale,

Divide their cm3/s/cm2 value by 0.508 for the CFM conversion.

[hwc 1954]

My strategy, although I am not always successful in implementing it, is to dress lightly enough to be comfortable on the uphill climb, then immediately throwing on a layer when I hit tree line or the summit exposed to the wind. In the summer, that's often a wind shirt. In the winter, it's probably a lightweight down hoody or a softshell. Then, I will usually leave an extra layer on for the hike back downhill, which is nowhere near the same level of exertion.

I'm realizing that on really cold days (20F and below), I might have to wear an extra layer (like a wind shirt) for the first 15 to 30) minutes while I'm getting warmed up, then stop and take it off for the bulk of the climb. Otherwise, I've got to start out in something that is going to feel very cold at the same time I'm trying to get properly warmed up from an exercise standpoint.

[St. Effen]

"It's easy to make a calendered SUL fabric which looks good on paper but breathes like crap (Tachyon, Ghost Wisperer, Quantum GL all fit here). Personally, I'm willing to carry 6-7 oz v. 3-4 if I can bust brush and not worry about snags."

+1

The search for a windshirt which ticks all my boxes (decent fit, hooded, full-zip, not too flimsy, <7 oz. (200 g), decent breathability, straightforward DWR renewal, reasonable price) took me quite some time. While the first five criteria were easily met by the Arc'teryx Squamish the last ones were a bit harder to meet.

Yes, I wanted something similar to the Squamish – but made of another fabric (and a bit less expensive). I remembered my favourite shirt in terms of breathability and maintenance: an old 1990 berghaus windsmock made of a polyester microfiber fabric (a tad too burly and color design by a color-blind brit) – no calendering, no coatings, no-fuss. So this would be it – a cheapo Squamish made of Poly.

I found a decent compromise (at least for my needs) and it was a real bargain at 65 Euro (would be around $75 today, not sure if you can find it in the US): Norrona Bitihorn Aero 60 Jacket. OK, not perfect (hood without volume adjustment, shapeless brim, crappy cord locks, fraying edges inside the stowaway pocket), but well worth a look.

Just my $0.02.

Cheers,
Steffen

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