New Zpacks hooded windshirt

I don't think RedBeard was sponsored. He just really liked the jacket, his version was grey, and he wore it a lot with his patagonia hoodie. Said it was toasty warm while hiking. But not everyone has the same metabolism. I run hot so rarely need a mid layer or wind layer but I have had to use my Houdini once in a while.
Anyhow, wearing a windshirt is subject to how it fits into your kit and systems. My Houdini has saved my butt a few times in unexpected situations at home where I used it with my umbrella in some unexpected, nasty hail storms at 9,000 feet, where I had to keep moving to stay warm. It's an older Houdini.
But on a long trail like the PCT I take a more substantial rain coat and leave the Houdini home, it's redundant to carry two tops like that. For me personally.
So it's a matter of what conditions you anticipate and if the windshirt fits into your kit and do you need it/like it enough to carry one?

" It is a dangerous path to add heavier options …"
That's relative. What are you with something lighter, if it doesn't make you feel comfortable ? That doesn't mean that weight is not taken into account, just that there are other factors that can be as important. :-)

Bringing a windshirt when not needed ? Again relative. I remember at least one hike where it started to rain heavily, I had my windshirt on, I took my rainjacket to put it on, took it back off, and got soaking wet in my windshirt as it was then still way more comfortable for just wearing my windshirt and getting soaking wet then to wear my rainjacket and stay reasonably dry.

I'm certainly no expert on vapor transfer stats or how they work. Is it different when a layer is pressed up tight against a thin wool base under a slim-fit fleece? Perhaps I'm buying into marketing hype, but, in my imagination at least, my sweat is evaporating somewhere between the windshirt and fleece. I don't sweat vapor after all.

Yes, it's not as warm in this arrangement, but that's missing the point. The point isn't to get maximum warmth/weight at all times; it is to get the right amount of warmth at the right time. I'm trying to *manage* warmth to stay comfortably cool. I'm already carrying base, windshirt, fleece, and rain protection anyway, so it all weighs the same regardless of how I arrange it. Wearing windshirt under fleece is pretty freaking warm and works for me while hiking in the 20-35F range, basically eliminating the bitter wind chill effect I would get with fleece alone. Above that I take off the fleece. Below that or when I stop I throw my baggy rainshell over the whole thing. I agree that without rainshell I'd probably get more warmth from the windshell over fleece. But with all 4 layers (which I'm carrying anyway) I think I get maximum warmth, when I need it, from base/windshirt/fleece/rainshell arrangement. [Edit: Looking into my crystal ball, I see that this "4-layer sandwich" system has become dogmatic received wisdom at BPL in 5 years. I feel totally vindicated. ;) ]

I can't take credit for any ideas here. Joe describes this arrangement and, while it seemed odd to me at first, I thought it worth trying. Hence, I'm testing it out on the conditions I happen to have now, which are fast day hikes in the 20-40F, ~80%ish humidity range. This is all in anticipation of spring/summer backpacking. My thought now is that it adds a whole lot of warmth and versatility for 1.9 oz.

Vapor barrier clothing is used to keep sweat from migrating into lofted insulation and freezing there. That only happens in very cold temperatures.

If you are wearinga base layer and wind shell and put a fleece on top, you will be warmer, but not as warm as wearing the fleece under, especially in cold wind.

Think of a windshirt as a shirt rather than a jacket. I wear it to aid my base layer when it is windy, cold and/or sporadic LIGHT precip. If it doesn't breathe well, it is just a big plastic bag and useless for active walking.

IMHO, the marketing of these SUL wind garments with little or no breathabilty is a scam. It is simply making something light for lightness' sake, with no regard for the actual use and perforance and the epitome of "stupid light".

A Supplex style fabric at three or four times the weight would be more useful. In fact we had such garments decades ago and they worked well— other than the weight. If you are only wearing a shell for use in camp or rest stops, your rain shell would be just as effective.

Furthermore, the question repeatedly comes up regarding the stubstution of a windshirt as a rain shell. Thee answer is categorically NO, and doing so is risking hypothermia or at least a very cold, wet and unpleasant hike.

My $0.02

The easiest way to look at using a wind shirt is in a simple manner. A wind shirt is used for moving and an insulation layer is used for stopping. Therefore, a wind shirt must be breathable enough to allow the moisture that your body accumulates via hiking (i.e. sweat) to be moved away from your core but at the same time block sufficient wind to prevent body heat loss via convection. That sweet spot means having a fabric with somewhere around 5 – 7 CFM because it will allow some breathability, some wind blocking, and some water resistance. I only use my wind shirt at high altitudes so take that with a grain of salt. I can't think that 0.75 CFM would be good. Just my perspective, however.

As I said above, I may be suffering from market hype and placebo effect (which is always proportional to $$ spent of course). However, my question above hasn't been addressed. Basically, should I believe that "wicking" is pure BS and CFM the *only* factor I should consider for sweat management?

I'm new to windshirts so – even if I don't believe something now – it's possible that real info might sink in after I've had time and experience with it. As to rainshells, I've become quite convinced that CFM is a small factor compared to ventilation. Hence, my rainshell is baggy with extra openings while my windshirt is slim for on base layer fit. I never ever considered that this 1.9 oz thing would substitute for rain protection. However, the converse works though: my rainshell adds sufficient wind protection when my 1.9 oz windshirt isn't up to the task.

Charlie,

You said, " Basically, should I believe that "wicking" is pure BS and CFM the *only* factor I should consider for sweat management?"

Wicking is pure BS for DWR coated shells, but it is how cool to cold weather, tight fitting base layers optimally function (hydrophilic surface). CFM is the function to measure how much water vapor can move through a DWR micro-porous wind shirt or hard shell (hydrophobic surface).

If you want more detail:

Source: http://alcheme.tamu.edu/?page_id=6780

Thanks for the link.

Hence, DWR should make it a poor wicker even when worn "as a base layer". Well, maybe it'll get better with wear then… ;)

Reading about Camp brand proprietary Araneum fabric is appreciated.
http://www.golightgofast.com/2012/05/wiki-araneum-fabric.html

If I didn't already have a wind shirt, I would like try it.

But reading still results in risking $100 or more to find out.

Here is some practical and useful information: http://youtu.be/a553JHrxSRA

I have the Mountain Hardwear Ghost Whisperer Anorakwind shirt.

My experience is like his experience.

Wicking is a contact thing— think of a lamp wick. The idea is to get the moisture away from your skin and continue to move it out through your BREATHABLE shell. That's where a little airflow is a good thing.

You may perspire a lot without having wet skin, remaining vaporous in your layering system and condensing wherever it gets cool enough.

Richard Nisely once posted that ~35cfm [edited for my error] gives a good balance, where a greater cfm doesn't move more moisture, but there is more heat loss. The pre-2013 Houdini was about 35CFM. See http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/95378/index.html?skip_to_post=809818#809818 for more.

Weight is the game here. There are lots of nylon athletic shells in the 10oz range with good breathability, vents, pockets, cuff adjusters, etc. You can wear a Supplex button front shirt (REI, OR, Columbia, Mountain Hardwear, Ex Officio) and get LOTS of airflow. They are up there in the 10-12oz range. The "Darth Vader" test works well for me to get a rough measure of breathability.

Connie,

CAMP wind shirt = Mountain Hardwear Ghost Whisper Anorakwind shirt = ZPacks wind shirt

The above will all pass water vapor at about the same rate as a quality rain jacket; they will not keep you any warmer than a quality rain jacket; they all will add extra weight to your pack if carried in addition to a quality rain jacket; and, none of them will protect you from the rain.

SIGH

"CFM is the function to measure how much water vapor can move through a DWR micro-porous wind shirt or hard shell (hydrophobic surface)."
So what is MVTR? Genuine question.

William,

MVTR is the term primarily used to describe how much moisture you can move through a solid membrane via Brownian Molecular Movement. There are at least six different tests that don't correlate. Each vendor uses the test that gives it the largest number and frequently don't tell you which test they used. Furthermore, the pressure on each side of the membrane can be varied over a test tolerance range by changing the air gap, temperature, or relative humidity.

The MVTR test that most closely correlates with the real world is the DPMC. The membranes that provide the highest DPMC numbers are the ones that are the most air permeable.

In order to be rainproof, the CFM number will typically be .5 CFM or lower. Rain gear membranes have lots of uniform small sized pores. Fabrics typically have fewer large sized pores. As a result, for the same CFM number the rain gear membranes will have a much higher hydrostatic head.

"Are these light weight options that useless?"

Pretty much. Seems like most of the ~2oz rain shirts are not very breathable. The MB Tachyon may be the most breathable of the bunch, I would check there. You could also check with Luke's UL. I think he makes an Argon wind shirt which will be pretty breathable and silly light. Argon does well on the Darth Vader breath test.

Ryan

"I think there is a way to use a wind jacket and a way not to. Most don't use them correctly. If I want less wind I wear my rain jacket.

This jacket seems like the worst of all worlds. Not breathable enough to be a highly effective wind jacket and not water resistant to be a highly effective rain jacket.

I wonder if RedBeard is a sponsored hiker?

To each their own, I guess."

Dave U

You said it!

…but also don't forget that RedBeard said it was good, so it is so!…. All hail RedBeard! All hail ZPacks!…

KJ

Conditions and the user can make some differences in the effectiveness of these less-than-breathable windshirts. A hike on near level ground in cold dry conditions is a different thing than miles of steep switchbacks in 40F weather with 90% humidity. The user's metabolism/conditioning is another factor. At my age and condition in the terrain

With that in mind, I've had the opportunity to try a number of wind shells in cool humid conditions and I would use a rain shell with good ventilation features before sinking $100+ in a garment for active use with little or no breathability.

Don't fell left out as a hiker: the wind shell options in the cycling world are just as bad and there is *always* a breeze on a bike with lots of activity. Runners and cross-country skiers have the same challenges.

I think it illustrates the issues with good applications of the physics of clothing systems and user physiology for active outdoor pursuits. IMHO, it is the same blinders-on approach that fills packs full of heavy and unneeded equipment. The way out of the traditional hiking box is looking at gear empirically, without emotion, sentiment, or status (aka "fashion"). In this case the pendulum has swung to a "only lightest is right" mindset that leads to poor choices in product design— which is the "stupid light category. We all want the lightest load, but the items we choose need to work! Given the choice of a 2oz product with questionable performance vs a 4oz version that works well, my spreadsheet (and my back) can handle the difference.

^^ Right on!

"they all will add extra weight to your pack if carried in addition to a quality rain jacket; and, none of them will protect you from the rain."

+1 Which leads to the question: Why bother to carry a wind shirt when you can achieve the same purpose with a UL WPB? which then becomes multipurpose gear. I haven't used a wind shirt in years for that very reason. I know, some will protest that a WPB doesn't breathe well enough when on the move, but I have seldom encountered conditions when I wasn't putting off enough heat while moving that I felt the need for a wind shirt. On the few when I did, I put on my WPB, Montane Minimus in my case, and slowed down enough to offset its decreased breathability. It has a very deep chest zipper, which greatly aids in venting and heat buildup. YMMV, as always.

Who's Redbeard? Do I need to know? And probably more useful to me, what is the Darth Vader test?

Thanks Richard! I find your comments to be the most useful and persuasive. Well, logic tells me that the added heat-retention I do feel from this thing (when used with rain shell) is entirely from vapor barrier. But if I want that then perhaps I should bring a Glad Bag instead. I'll probably have to experiment more before reality seeps fully into my brain.

I think people forget that repeatably using a rain jacket kills it's effectiveness. Using a rain jacket instead of a windshirt kills its DWR faster and even the best rain jacket is still less breathable than a windshirt. I tried using a zpacks rain jacket (more breathable white version) instead of a windshirt, and even the new Houdini trumped it in breathability. Plus for a couple more ounces I have something that will stand up to more wear and tear and add to my layering system.

DWR is renewable. It's wet enough here that I'll always pack a rain jacket.

I've always thought the windshirt was an excellent complement to a poncho(-tarp) system.

I suppose you could argue that you're wearing a full-fledged, multi-layered rain jacket, a windshirt is going to largely duplicate functionality. But it's going to keep you from getting chilly if you're wearing airy, open poncho for rain protection. Of course, a poncho usually is airy and open given it's water proof nature.

" what is the Darth Vader test?"

Trapping a section of fabric against your mouth and attempting to breathe through it. It's a great way to test fabric breathability in the store, however odd it looks.

I like Red Beards description.

I like the pre-2011 Houdini 25 cfm description.

I like a wind shirt. I especially like a UL windshirt because it is lightweight and low volume in my backpack or in my pocket for windy conditions worn over my first layer after underwear.

I have rain wear for real rain.

"I think people forget that repeatably using a rain jacket kills it's effectiveness. Using a rain jacket instead of a windshirt kills its DWR faster and even the best rain jacket is still less breathable than a windshirt."

For some of us it's not a matter of forgetting. It's simply analyzing the requirements for the area(s) we hike in and selecting gear accordingly. In my case, I hike mostly 3 seasons in the Sierra, where it rarely rains long enough for me to have to hike with a pack on, and I have no need to hike with a wind shirt, for reasons I explained above. This has led me to conclude that I can get away with one less piece of gear, a wind shirt. So far, so good in the field. I used my Minimus for 2 seasons before having to re-apply DWR, which is not too bad for such a lightweight jacket. Works for me, may not for others.

For hiking in the Cascades, I use an Integral Designs WPB instead of the Minimus because it will see much more use, often in areas where a Minimus would not hold up to the abuse. Different application, different gear. In neither case have I felt the need for a wind shirt. YMMV, as always.