Shell vs. Insulation

Now you know a bit about the technologies involved in outerwear production. The next step is to dive a bit into basic outerwear construction. One of the most common questions is whether to go for a shell, or an insulated piece. These designations are pretty simple, so I’ll keep this brief.

Shells – Versatility

The good: Shells are extremely versatile and can be made with the most technical constructions. A good shell can be worn in absolutely any weather scenario. It has the flexibility to perform well on a hot day in the pouring rain, or in blizzard conditions well below freezing. The only thing you need to modify is your layering.

Burton Hover Jacket.

The 3L Burton Hover Jacket, a shell.


The bad: Shells offer little to no inherent insulation. They are not warm and require insulating layers to be warm.

Insulation – Warmth

The good: Insulated outerwear has insulation integrated into the garment’s construction. These pieces can be extremely warm on their own.  You don’t have to deal with layer incompatibilities (i.e. a “grabby” fabric versus a “slippery” fabric).  It can also be cheaper in the long run, considering that good layering can cost a decent amount of money on its own.

Orage B Dog jacket.

The Orage B-Dog, insulated jacket.

The bad: Insulated outerwear is much less versatile then a shell. Too much insulation can cause you to overheat easily, even in cold temperatures. This happens for two reasons. The obvious reason is that the jacket has insulation that can not be removed. Less obviously, the breathability of an insulated jacket is also limited by the breathability of the insulation, regardless of fabric technology. Bottom line, if you need a really warm jacket and are willing to buy multiple jackets for multiple weather conditions, insulated may be for you.

2L vs. 3L Shells

Here is an important question when purchasing a shell: 2 Layer or 3 Layer? And does it really matter?

2L – The Original

2L garments are constructed with two layers; a nylon face fabric (generally with a DWR) that is bonded to a WP/BR laminate. 2L garments are always lined with some sort of lining fabric. These linings are generally made of thin nylon or mesh, and serve two purposes. First, the lining keeps the laminate from direct contact with the skin. This is important because the laminate generally has a plastic feel to it and can be quite uncomfortable.

The lining’s main purpose, however, is to protect the laminate. Even though the laminates are engineered to be resistant to fouling, without further protection of the laminate, its durability can suffer greatly. 2L garments are generally constructed with some amount of seam taping. Seam taping keeps water and wind out at the seams, but does not breathe.

2L outerwear dominates the market for many reasons. 2L construction lends itself quite well to making insulating garments, which dominate the consumer market. (People want their coats to be warm. Who knew?) 2L construction is also less expensive because the technology has been around much longer. The construction of the garments is easier because the lining allows many sewing options with less need for seam taping, and the design is easier because of the ability to work with a lining.

3L – Or, Why does this jacket cost $600???

3L garments are constructed with 3 layers: (1) a nylon face fabric (with a DWR) that is bonded to (2) a WP/BR laminate, which is bonded to (3) a tricot layer on the inside.

3L construction: blue = nylon face, yellow = WP/BR laminate, orange = tricot liner

3L construction: Blue = nylon face; Yellow = WP/BR laminate; Orange = tricot liner.

3L garments are not constructed with a lining and are therefore often shells. 3L pieces generally use the most advanced (and therefore expensive) fabrics and laminates. These fabrics make up some of the most technical pieces of outerwear available. Construction of 3L garments is difficult. Every seam has to be taped or welded, and every cut greatly modifies the look of the garment. Given that both seam taping and the fabric are extremely expensive, and construction is difficult, 3L garments can be costly pieces of outerwear.

So why bother to make (or buy) a 3L jacket, when you could just produce or purchase a 2L jacket?

There are a few reasons why 3L construction has gained a lot of momentum in the industry lately. First is performance: the addition of the bonded tricot liner increases the breathability of the garment. The tricot is hydrophilic and, as you sweat, the tricot preferentially absorbs your sweat and transports it to the laminate so it can diffuse out. Contrast this with a 2L garment, where the water vapor has to randomly bump into the laminate while navigating between your skin and the lining to diffuse out.

The next advantage is weight. 3L garments can be made without a lining, and therefore, save a substantial amount of weight when compared to their 2L counterparts.

The final advantage is the durability of 3L construction. The addition of the tricot liner adds a significant amount of support and protection for the laminate that is not present in a 2L garment. In short, a 3L garment will have better performance, with less weight, and be more durable than a comparable 2L design—albeit at about twice the cost.

2.5L – Or, What in the hell is a half a layer?

This is not a very common construction in the world of winter outerwear, but it is a common source of confusion, so we’ll briefly touch on it.

A 2.5L fabric is made up of two and half layers—sort of. It has a nylon face fabric (with a DWR), a WP/BR laminate, and then a printed lining. This printed lining is present for the sake of protecting the laminate, but does little to eliminate the clammy, plastic feeling of the laminate directly on the skin; hence the designation of a half of a layer. 2.5L fabrics are used on active rainwear because they are easier to produce and end up being lighter than 3L garments, though less comfortable.

What does it all mean?

Hopefully you’re now in a better position to make an informed decision when purchasing your next piece of outerwear. The most general take away is: Beware of performance ratings, and find a good DWR.

Beyond that, let personal preference (and your wallet) be your guide to picking out your next piece of outerwear.

Buying outerwear is a process. It almost always sucks, at least until you are standing in the backcountry or on top of your local hill, in a white out, completely comfortable.


  1. Amazing article. Thanks so much. So enlightening.

    Keep bringing it!


  2. Freaking killer articles. All of them. Even as a seasoned gear shop employee and tech junkie, can always count on Blister to deliver the goods on beta, science, and the layman’s terms to tell the whole story.

    Keep up the really really ridiculously awesome work.


  3. Thanks for the kind words fellas!

  4. genius. i’ll never look at gore-tex the same way again. nice work man.

  5. Such an interesting perspective on technical outwear, and an entertaining read!

    Thanks for the great article!

  6. Amazing article. Can’t believe I missed this when it came out. Blister FTW.

  7. Wow. Technical yet totally accessible article. Great, great read for anyone looking to buy waterproof, breathable gear. I learned a lot & will try to spread the word about this article. Thanks!

  8. Really in depth article, but really useful even for the non technical out there. You covered some great points. Time to go shopping for the right balance of tech in my new jacket! I’ve shared this on our Facebook, will be really useful to our followers.

  9. Finally, an article that doesn’t reduce a complex issue to a couple of bullet points. Thanks!

  10. Terrific article! Might I suggest for Outerwear 102 and article about actually dressing for skiing/boarding? How are the various layers supposed to be used? What do you guys wear for different conditions? Two layers? Three layers? How should you layer under a shell? Think would be a useful companion. Keep up the great work!

  11. Great Article!
    Was just about to buy 3L Gore pants… Questioned my choice (and the price)… Found your article… Read the whole thing… And just ordered the pants!
    It confirmed my decision — also answered my long wonder about how the 20k/20g (etc) ratings compared to others and if they really could be trusted. Answer = no more board shop employees trying to sell me over priced claimed “technical” wear.

    • Hey Dan, glad I could help out!

  12. This is a fantastic article. Where does Dermizax fall? I keep seeing the material in very high end Kjus ski jackets; is it simply a PU laminate? If so, I can’t imagine the performance would warrant the $1500 price. They claim incredibly high breath ability scores, but thanks to your article I now know to ignore them :) There also appears to be several versions of Dermizax. Is this material any good?

  13. Most helpful article. Thank you Sam for the time and effort you invested to write this!

  14. Great article, nice to see one of these that doesn’t spew the misinformation of water drop vs vapor molecules through holes stuff.
    The one thing you didn’t stress was the effect of shell and liner fabrics on breathability of the total laminate.

  15. stupendous and layman friendly article! it took me a few minutes to fully absorb (he he) all this ‘dry as a bone’ information to great effect. no ‘watered down’ or fishy patent references to get wallowed down in either! wish there were more ‘commercial’ PR folks who had the smarts to actually divulge facts, rather than foist their marketing jargon upon so many naive buyers!

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