I have gotten dozens of people asking me about which one they should buy, if there are any real-world differences between the fabrics – both for breathability and water resistance – and all those type of questions.
From a usage perspective the only one of these wind jackets that I have personally used is the Montbell Tachyon – something I have extensively used, put to the test, and reviewed.
For help with this article I have contacted a fellow by the name of Richard Nisley who is widely known and very well respected within the BPL community. He has the tools and resources to test fabrics at a level few of us have. I have often cited his research in my whitepapers and publications.
I asked him the following questions:
Which fabric, of these three jackets, will block the most wind, if breathability is not a factor?
The key part of that question was “if breathability is not a factor” – in other words, which of these three fabrics is the ‘most wind resistant‘.
His response was, from best to worst:
ZPacks Wind Shell, Patagonia Houdini, Montbell Tachyon.
It is important to remember that wind jackets are typically, as I have tended to find by reading what others talk about in regards to how they approach using wind jackets, divided into two groups:
The first group are those people who use a wind jacket for nothing more than blocking the wind. These are folks that use a diverse layering system to counter other factors such as (a) thermoregulation of core and peripheral body temperature, and (b) rain/snow.
The second group are those people who use a wind jacket as an active layer of their base layering system. To them, a wind jacket is factored into helping them control thermoregulation and to provide an initial layer of light rain/snow protection.
I think this first question that I asked Richard is a key question to look at, because it addresses both the issue of those who approach their wind jacket as only wind protection, and those who use their wind jacket for something beyond just a wind jacket.
Because, as most of us know, breathability is a key aspect in all of this. If a garment does not breathe, that forces a person to counter how to deal with the build up of body heat and body condensation.
So based on Richards testing, if you are after a wind jacket that will give the maximum about of wind protection AND cause the maximum about of body heat and body condensation, the ZPacks Wind Shell is going to be your best option.
Ok, so what if you want a wind jacket that is going to breathe and not cause you to build up body heat and perspire as fast as the ZPacks Wind Jacket will?
Well, I went on to ask him:
If you were to pick one that was a “happy medium between wind and breathability” which would it be?
He responded: The Montbell Tachyon.
Richard has often written about how well the Patagonia Houdini fabric performs so from a purely numbers perspective, I was not expecting that response. The difference here, as I am to take it, is much like the issue with the ZPacks Wind Jacket: a fabric can be really good at one thing, yet perform not so good at another thing. In the case of the Patagonia Houdini, it seems that it is really good at being able to breathe, but its ability to block wind leaves it lower side of that scale. Just opposite of the ZPacks Wind Jacket.
He was kind enough to share with me the following information, based on his testing of fabrics over the last few years. I realize it uses some technical jargon, but hopefully it gives some further insights into these different fabrics.
John, I have measured most of the fabrics you asked about:
.53 CFM — ZPacks Pertex GL (my test results)
.53 CFM — ZPacks Ventum (not measured by me but ZPacks claims it is equivalent to the Pertex GL)
3.73 CFM — Patagonia Houdini (my test results)
9.72 CFM — Montbell 7 denier Ballistic Airlight (my test results)
Considering that the most air permeable true rain garment is .5 CFM, all windshirts are equal to or better than the best rain gear for air permeability. Air permeability is generally inversely proportional to the hydrostatic head. In addition, all fabric weaves have a small amount of big pores rather than a large amount of small pores found in air permeable rain gear. No windshirt is adequate for true rain (1,500 mm H2O min required).
Air flow in the 35+ CFM is optimal for the balance between dumping moisture from sustained aerobic activity (7 MET which is the average person’s maximum sustained rate), good wind resistance, and medium precipitation protection.
Air flow in the 70+ CFM is optimal for the balance between dumping moisture from sustained aerobic activity (>7 MET which is an adventure racer’s maximum sustained rate), helpful wind resistance, light precipitation protection. Conventional summer shirt weaves are typically also in the 50 – 70 CFM range.
So I guess in closing here, based on the data that Richard has been able to test and compile:
“Montbell Tachyon” == the best middle-of-the-options for both wind protection and breathability, yet this means some wind penetration and some body core temp increase.
“Patagonia Houdini” == the best option for breathability, yet some airflow getting through, which could result in a body cool down due to super cold wind penetration.
“ZPacks Wind Shell” == the best option for blocking the most wind, yet not breathing so expect body core temp increase and thus sweating more.
Interesting, Inov-8, a company well known for award winning running shoes, has introduced their first shell, called the “Inov-8 Race Ultra Shell HZ” and I cannot lie… I want one of these! It is a 4-way stretch, 2.5 layer, waterproof shell that should excel at breathability, rain resistance, and wind resistance – and is only 125 grams (4.4 ounces). So while it is significantly heavier than these three other jackets talked about, it has the potential to be both a full-on rain shell and a wind jacket. Of course, its going to take folks getting real-world use out of it, and somebody like Richard getting his hands on the fabric to put it to the test, before we can really determine its worthiness, but the idea of a sub 5 ounce shell that can be a master of both wind and rain, that peaks my interest.