Arc';teryx Jacket

Picking the Perfect Arc’teryx Puffy:

A head-to-head comparison review of synthetic Arc’teryx Puffy Jackets. Specifically the Quantum Series which includes the Proton, Atom & Nuclei.

Walking around an outdoor gear store, or perusing one online for that matter, can be both fun and intimidating. There’s an absolute mountain of choice (yes, the pun was intended) when it comes to good quality kit! Now, a wide selection can be a great thing as it allows you to find the perfect item to suit your application. Or, it can be an absolute pain in the ass when all the subtle differences between options blur into a quagmire of indecision.

Of course this abundance of choice can be found in a lot of different areas but one that’s particularly prolific in the outdoor industry is insulated jackets. But that’s where this article comes in. We’re going to focus on how to select the right puffy jacket for you. I don’t want to go down the rabbit hole of synthetic vs. down at this point so we will be focusing solely on jackets with synthetic insulation.

Arcteryx Jacket
Picking that one perfect puffy jacket for a given activity is not always easy!

To facilitate this discussion we’re going to compare three different Arc’teryx puffy jackets: Proton, Atom & Nuclei. Why Arc’teryx? Two main reasons. First, they make very high quality, well thought-out gear. Second, because of the relative simplicity of their naming system. A given category of jackets will keep the same name but utilize different descriptors to identify how heavily insulated it is. The Atom, for example, comes in SL, LT and AR versions. This makes it simple to separate how warm a jacket is from the type of use it’s designed for. A very user friendly system once you know it.

Table I: Arc’teryx Apparel Naming Scheme

Arc'teryx Naming Scheme
A summary of the current acronyms used by Arc’teryx when naming various garments. Some of the same names also bleed over into other areas such as footwear.

Each of the insulated jackets that we’re looking at have been designed with a different use in mind, though they can look very similar on the surface. So how do you select the right jacket? First, pick the type of jacket based on the use: active insulation, mid-layer or top-layer. Then decide what weight of insulation is needed for the general temperature range in which you’re planning to use it: SL, FL, LT or AR depending on the line. So, let’s get started…

The Line-Up of Arc’teryx Puffy Jackets:


  • Primary use: Active Insulation Layer
  • Variations: FL, LT & AR (FL not available until 2019)


  • Primary use: Insulated Mid Layer
  • Variations: SL, LT & AR


  • Primary use: Insulated Top Layer
  • Variations: AR only


Arc'teryx Proton AR
Arc’teryx Proton AR

The Proton is an active insulation layer. That means it’s designed to be worn as a top (or mid) layer during variable output activities such as climbing, mountaineering, hiking, etc. It provides some warmth and wind protection while allowing enough airflow that sweat can dissipate and the wearer doesn’t overheat. To facilitate this the Proton has the following attributes:

  • Air Permeable / Breathable: High
    • Internal and external fabrics designed to breathe.
    • Breathable insulation.
  • Wind Resistance: Moderate
    • The exterior fabric cuts the wind a little but not so much as to impact airflow and breathability.
  • Water Resistance: Moderate
    • A DWR (durable water resistance) treatment is applied to the fabric to allow it to shed some water but is not designed for continuous precipitation.
  • Compressible / Packable: Low
    • As an active insulation layer it’s designed to be worn, not packed.
  • Fit: Trim
    • Designed to be worn with minimal underlayers so has a trim fit over the body with fairly long sleeves.

Best Use: Put it on for some extra warmth during stop-start or moderate to high intensity activity and just leave it on.

Available Weights:

  • Proton FL: Lightly insulated, a great spring-summer-fall layer (Available spring 2019).
  • Proton LT: Slightly heavier fabrics, a great fall-winter-spring layer.
  • Proton AR: The warmest of the bunch and really a cold weather jacket. If you’re out making it happen in the blistering cold this is the one.
Arc'teryx Proton FL
Arc’teryx Proton FL living up to it’s name on a fast-and-light traverse of the Tantalus range.


Adam LT
Arc’teryx Atom LT keeping me warm on a cool day in the desert.

The Atom is designed primarily as an insulated mid-layer but of course can be worn as a top layer as well. It’s really a jack-of-all-trades kind of jacket which is likely why it’s such a popular piece, especially the Atom LT. It provides some extra warmth when needed, is soft and comfortable to wear, fairly packable and still reasonably breathable. What’s not to like, right?

  • Air Permeable / Breathable: Moderate
    • Some of the fabrics vary by jacket model (SL vs. LT vs. AR) but basically the heavier the insulation the less breathable the fabrics used. The fabrics are less breathable than those used on the Proton.
    • Uses a slightly less breathable version of the Coreloft insulation used on the Proton.
  • Wind Resistance: Moderate
    • The exterior fabric is designed to cut the wind and reduce heat loss. The SL & LT versions have fleece panels under the arms that are not wind resistant but very breathable.
  • Water Resistance: Moderate
    • A DWR treatment is applied to the fabric to allow it to shed some water but is not designed for continuous precipitation.
  • Compressible / Packable: Moderate
    • As a mid-layer the Atom is designed to be compressible for easy storage in a pack.
  • Fit: Trim
    • The lighter Atom’s are not designed to be worn over much and so have a fairly trim fit while the AR version has a slightly looser regular fit to accommodate a thicker base layer. The torso is cut a bit short to allow the jacket to fit well under a shell layer.

Best Use: Packed as an extra layer that can be thrown on when needed and taken off when not. More common use is to just wear it for everything.

Available Weights:

  • Atom SL: Very lightly insulated with mesh lined sleeves for use with a t-shirt. A great warm weather layer.
  • Atom LT: Heavier fabrics and more insulation, a great mid-weight, year-round insulation layer except for mid-summer and mid-winter.
  • Atom AR: The warmest of the bunch, it’s designed mainly as a winter jacket where it works as either a top or a mid-layer.
Arc'teryx Puffy: Atom
Small strips of fleece are found under the arms the on the Atom LT (left) and SL (right). They allow the jacket to breathe better while also providing some stretch. The mesh interior sleeve fabric can also be seen on the photo of the Atom SL.


TArc'teryx Puffy: Nucleihe Nuclei is designed as an insulating top layer or puffy over-jacket/belay jacket. Something that gets thrown on over other layers at a belay stance, at the top of a long skin track or at a cold camp/bivvy. It’s lightweight and compressible making it an easy layer to pack around until needed. And while the main focus of the jacket is to keep the elements out and warmth in, it’s still able to breathe. This ensures that sweat and any snow or ice that’s stuck to other layers isn’t trapped. Here’s where the Nuclei stacks up:

  • Air Permeable / Breathable: Moderate
    • The exterior composite fabric features a GORE Thermium® membrane which is fairly breathable.
    • The Nuclei utilizes the same type of Coreloft insulation as the Atom LT &  AR. It’s reasonably breathable but less so than the insulation used in the Proton jackets.
  • Wind Resistance: Very high – Wind Proof
    • The GORE Thermium® composite fabric is not just wind resistant, it’s windproof.
  • Water Resistance: High
    • With a durable light rain resistant membrane, seam sealed construction and a water repellent outer fabric treatment the jacket is highly water resistant, but it’s not a waterproof shell by any stretch.
  • Compressible / Packable: High
    • The Nuclei comes with an integrated stuff-sack and has been designed with features like a micro-seam allowance to reduce bulk and improve packability.
  • Fit: Relaxed
    • Designed to be worn over other layers and so features a more relaxed fit and a longer torso to cover the butt.

Best Use: Thrown on immediately after a high output activity to trap in heat but not sweat.

Available Weights:

  • Nuclei AR: Mid-weight insulation when compared to other belay jackets. A great 4-season option that’s ideal for winter, spring and fall use when the temperatures aren’t too cold.

Note: The AR is currently the only model in the series. SL or FL type insulation levels wouldn’t make a lot of sense for this type of insulating over-jacket. On the other hand a heavier, SV type version would be logical if it weren’t for other jacketslike the amazing Duallywhich already address that particular need.

Arc'teryx Puffy: Nuclei
Arc’teryx Nuclei AR worn over the Atom LT. With a slightly looser fit and long torso it’s designed to be worn over other jackets.


Table II: Arc’teryx Puffy Jacket Attribute Summary

Arc'teryx Puffy Jacket Comparison
Arc’teryx Puffy Jacket Comparison

The above table is a bit of an oversimplification in some ways as different versions of each Arc’teryx puffy jacket are available, with the exception of the Nuclei. For example, the Atom AR utilizes a blend of Coreloft insulation in weights up to 120g/m2. The Nuclei, on the other hand, uses the same type of insulation but only up to 100g/m2. This means that the Atom AR is actually more heavily insulated than the Nuclei AR, but less water and wind resistant.

To help with the comparison, a summary of the different exterior fabrics and insulation types for the different Arc’teryx puffy jackets are listed below by jacket:

Table III: Arc’teryx Puffy Jacket Materials

Arc'teryx Puffy Jacket Comparison
Notes: The numbers in the fabric column refer to the denier, the numbers in the insulation column refer to the insulation weight in g/m2.

Using the above table it’s easy to see patterns in the use of the different fabrics and types of insulation. The further down the table the less breathable the fabrics and insulation are, but they’re also more resistant to wind and weather. Packability also improves lower on the table but of course is heavily influenced by the amount of insulation in a given jacket.

Arc'teryx Nuclei
The very packable/compressible Nuclei AR (black) next to the Proton AR (orange). The Nuclei is packed into the provided stuff-sack, while the Proton is rolled into the hood.
Arc'teryx Puffy: Nuclei
Arc’teryx Nuclei AR features the new-ish Gore Thermium.

It should be a lot easier to find the layer that best suits your activity now that you know the system and associated lingo. But what if you’re not planning to buy an Arc’teryx puffy jacket? No problem! The naming systems for the actual garments differ by brand of course, but the general ideas are all the same. For example, Patagonia’s Nano-Air Light is an active insulation layer while the Nano Puff is a mid-layer and the Stretch Nano Storm is an over-jacket.

I hope this article proves useful the next time you’re out hunting for that perfect puffy. If you want a bit more info on puffy jacket insulation and warmth check out this article by Canberk over at Outdoor Crunch: Temperature Ratings of Insulated Jackets.

Disclaimer: Black Sheep Adventure Sports was provided with a small sample of jackets to help with the review. Of course this didn’t influence us in any way.