We'll get to compare the Proton LT vs Nano Air and Atom LT vs Nano Air.
In terms of warmth, all three are the same. But what about other departments?
But first, you'd probably better go ahead and read the foreword of my Atom LT vs Proton LT article. I lay out some important facts about the Arcteryx's motivation behind launching Proton LT there.
If you don't have time, then let me summarize the part that concerns you:
- Atom LT started to lose its share when the advanced fabrics and insulation pieces were released into the market (such as Patagonia's Nano Air).
- Arcteryx's response against these higher technologies was to release a superior replacement to the Atom LT. And that was Proton LT.
This information is important for this comparison because it might be wiser to compare the Nano Air to the Proton LT instead of the Atom LT.
- #A sidenote here: Arcteryx.com's PDF guide to their jackets is GOOOLLDDD. Highly recommend you to check it out before you buy.
- Some of the Arc pieces you see in this post might be discontinued, and hence might be unavailable at arcteryx.com.
- If that's the case, then I'd recommend you to check out this page at REI. You might be able to find them there.
Approximate lowest temperatures you can wear each down jacket in the market without feeling uncomfortably cold are...
| Name | Est. Temp (F/C) | Insulation Material | Insulation Amount | Review | |||
|---|---|---|---|---|---|---|---|
| Arc'teryx Alpha Parka (Men's - Women's) | -17/-27 | Down | N/A | N/A | No | M | |
| Feathered Friends Khumbu (Men's) | -17/-27 | Down | N/A | N/A | No | M | |
| Arc'teryx Ceres SV (Men's - Women's) | -15/-26 | Down | N/A | N/A | Review | Yes | M |
| Mountain Equipment K7 (Men's - Women's) | -13/-25 | Down | N/A | N/A | No | M | |
| Rab Positron Pro (Men's - Women's) | -13/-25 | Down | N/A | N/A | No | M W | |
| Patagonia Grade VII (Men's) | -11/-24 | Down | N/A | N/A | No | M | |
| Arc'teryx Firebee AR (Men's - Women's) | -10/-23 | Down | N/A | N/A | Review | Yes | M W |
| Mountain Equipment Exo (Men's) | -10/-23 | Down | N/A | N/A | No | M | |
| Arc'teryx Thorsen (Men's) | -7/-22 | ParkaD | N/A | N/A | Review | No | M |
| Patagonia Frozen Range (Men's - Women's) | -6/-21 | ParkaD | N/A | N/A | Review | No | M W |
| Arc'teryx Centrale (Women's) | -5/-20 | ParkaD | N/A | N/A | Review | No | W |
| Rab Neutrino Pro (Men's - Women's) | -2/-19 | Down | N/A | N/A | No | M W | |
| Arc'teryx Therme (Men's) | -2/-19 | ParkaD | N/A | N/A | Review | No | M |
| Arc'teryx Dually Belay (Men's) | 0/-18 | Synthetic | ThermaTek | 92 g/m² | Review | Yes | M |
| Arc'teryx Camosun (Men's) | 0/-18 | ParkaD | N/A | N/A | Review | No | M |
| Arc'teryx Piedmont (Men's) | 2/-17 | ParkaD | N/A | N/A | No | M | |
| Arc'teryx Fission SV (Men's - Women's) | 3/-16 | Synthetic | Coreloft Continuous | 90 + 65 g | Review | No | M |
| Outdoor Research Super Alpine (Men's - Women's) | 3/-16 | Down | N/A | N/A | No | M W | |
| Patagonia Tres 3-in-1 (Men's - Women's) | 3/-16 | ParkaD | N/A | N/A | Review | No | M W |
| Arc'teryx Radsten (Men's) | 3/-16 | ParkaS | Coreloft Compact | 120 g/m² | No | M | |
| Patagonia Fitz Roy (Men's - Women's) | 3/-16 | Down | N/A | N/A | No | M W | |
| Rab Electron Pro (Men's - Women's) | 5/-15 | Down | N/A | N/A | No | M W | |
| Arc'teryx Macai (Men's | 5/-15 | Down | N/A | N/A | Review | No | M W |
| Arc'teryx Nuclei SV Parka (Men's - Women's) | 5/-15 | Synthetic | Coreloft Continuous | 190 g/m2 + 90 g/m2 | No | M W | |
| Patagonia DAS Parka (Men's - Women's) | 5/-15 | ParkaS | PrimaLoft Gold Insulation Eco | 133 + 40 g | No | M W | |
| Arc'teryx Patera (Women's) | 5/-15 | ParkaD | N/A | N/A | Review | No | W |
| Arc'teryx Cerium SV (Men's - Women's) | 7/-14 | Down | N/A | N/A | Review | Yes | M W |
| Black Diamond Access Down (Men's - Women's) | 7/-14 | Down | N/A | N/A | No | M W | |
| Arc'teryx Kappa (Men's - Women's) | 7/-14 | Synthetic | Coreloft Continuous | 140 g/m² | Review | Yes | M |
| Arc'teryx Prema (Women's) | 7/-14 | ParkaD | No | W | |||
| Arc'teryx Radsten Insulated Men's) | 7/-14 | ParkaS | Coreloft Compact | 120 g/m² | No | M | |
| Rab Microlight Alpine (Men's - Women's) | 7/-14 | Down | N/A | N/A | No | M W | |
| Patagonia Macro Puff (Men's - Women's) | 8/-13 | Synthetic | PlumaFill | 135 + 90 g | Review | No | M W |
| Feathered Friends Eos (Men's - Women's) | 8/-13 | Down | N/A | N/A | No | M W | |
| Arc'teryx Macai LT (Men's) | 8/-13 | Down | N/A | N/A | No | M | |
| Arc'teryx Seyla (Women's) | 8/-13 | ParkaD | No | W | |||
| Arc'teryx Koda (Men's) | 8/-13 | ParkaS | Coreloft | 200 g/m² | No | M | |
| Arc'teryx Thorium AR (Men's - Women's) | 8/-13 | Down | N/A | N/A | Review | No | M W |
| Arc'teryx Kole (Men's - Women's) | 10/-12 | ParkaD | No | W | |||
| Patagonia Vosque 3-in-1 (Women's) | 10/-12 | ParkaS | ThermoLite | 100 g | Review | No | W |
| Arc'teryx Alpha IS (Men's - Women's) | 12/-11 | Synthetic | Coreloft Continuous | 65 g/m² | Yes | M | |
| Patagonia Jackson Glacier (Men's - Women's) | 12/-11 | ParkaD | N/A | N/A | Review | No | M W |
| Arc'teryx Sensa (Women's) | 14/-10 | ParkaS | Coreloft Compact | 120 g/m² | No | W | |
| Patagonia Hi Loft Down (Men's - Women's ) | 14/-10 | Down | N/A | N/A | Review | No | M |
| REI Magma 850 Hoodie 2.0 (Men's - Women's) | 14/-10 | Down | N/A | N/A | No | M W | |
| Arc'teryx Atom AR (Men's - Women's) | 18/-8 | Synthetic | Coreloft Continuous | 120 g/m2 + 80 g/m2 + 60 g/m2 | Review | No | M W |
| Patagonia Downdrift (Men's - Women's) | 18/-8 | Down | N/A | N/A | No | M W | |
| Patagonia Down Sweater (Men's - Women's) | 19/-7 | Down | N/A | N/A | Review | No | M W |
| Arc'teryx Magnus (Men's) | 19/-7 | ParkaS | Coreloft | 80 g | No | M | |
| Arc'teryx Agrium (Men's - Women's) | 21/-6 | Down | N/A | N/A | No | M W | |
| Patagonia AlpLight Down (Men's - Women's) | 21/-6 | Down | N/A | N/A | No | M W | |
| Patagonia Topley (Men's) | 23/-5 | Down | N/A | N/A | No | M | |
| Rab Xenon 2.0 (Men's - Women's) | 23/-5 | Synthetic | PrimaLoft Silver | 60 g | No | M W | |
| Patagonia Silent Down (Men's - Women's) | 26/-3 | Down | N/A | N/A | Review | No | M W |
| Mountain Hardwear Ghost Whisp/2 (Men's - Women's) | 28/-2 | Down | N/A | N/A | No | M W | |
| Arc'teryx Cerium LT (Men's - Women's) | 28/-2 | Down | N/A | N/A | Review | No | M W |
| Arc'teryx Nuclei FL (Men's - Women's) | 32/0 | Synthetic | Coreloft Continuous | 65 g/m² | Review | No | M W |
| Patagonia City Storm Down (Men's) | 32/0 | ParkaD | N/A | N/A | No | M | |
| Arc'teryx Atom LT (Men's - Women's) | 36/2 | Synthetic | Coreloft Continuous | 60 g/m² | Review | No | M W |
| Patagonia Micro Puff (Men's - Women's) | 36/2 | Synthetic | PlumaFill | 65 g | Review | No | M W |
| Patagonia Isthmus (Men's | 36/2 | ParkaS | ThermoGreen | 60 g | No | M | |
| Arc'teryx Proton LT (Men's - Women's) | 37/3 | Synthetic | Coreloft Compact | 80 g/m2 + 60 g/m2 | Review | No | M W |
| Patagonia Nano Puff (Men's - Women's) | 37/3 | Synthetic | PrimaLoft Gold Insulation Eco | 60 g | Review | No | M W |
| Arc'teryx Norvan SL Ins. (Men's - Women's) | 39/4 | Synthetic | Coreloft Compact | 40 g/m² | Yes | M W | |
| Patagonia Nano Air (Men's - Women's) | 41/5 | Synthetic | FullRange | 60 g | Review | No | M W |
| Arc'teryx Cerium SL (Men's - Women's) | 43/6 | Down | N/A | N/A | Review | No | M W |
| Arc'teryx Proton FL (Men's - Women's) | 48/9 | Synthetic | Octa Loft | 98 g/m² | Review | No | M W |
| Arc'teryx Atom SL (Men's - Women's) | 52/11 | Synthetic | Coreloft Compact | 40 g/m² | Review | Yes | M W |
| The North Face Summit Down (Men's - Women's) | Testing | Down | N/A | N/A | No | M W | |
| Mountain Equipment Lightline Echo (Men's) | Testing | Down | N/A | N/A | No | M | |
| Mountain Equipment Kryos (Men's - Women's) | Testing | Down | N/A | N/A | No | M W | |
| Mountain Equipment Xeros (Men's - Women's) | Testing | Down | N/A | N/A | No | M | |
| Arc'teryx Andra LT IS (Women's) | Testing | ParkaS | Coreloft | 60 g/m² | No | W | |
| Arc'teryx Phoria IS (Women's) | Testing | ParkaS | Coreloft | 100 g/m² | No | W | |
| Feathered Friends Helios (Men's) | Testing | Down | N/A | N/A | No | M | |
| Feathered Friends Volant (Men's) | Testing | Down | N/A | N/A | No | M | |
| Rab Axion Pro (Men's - Women's) | Testing | Down | N/A | N/A | No | M W | |
| Feathered Friends Rock & Ice (Men's) | Testing | Down | N/A | N/A | No | M | |
| Rab Valiance (Men's - Women's) | Testing | Down | N/A | N/A | No | M W | |
| Rab Expedition 8000 (Men's) | Testing | Down | N/A | N/A | No | M | |
| Rab Zero G (Men's) | Testing | Down | N/A | N/A | No | M | |
| Rab Generator Alpine (Men's) | Testing | Synthetic | PrimaLoft Gold | 133 g/m2 + 80 g/m2 | No | M | |
| UBR Regulator Parka II (Men's) | Testing | ParkaS | PrimaLoft Innovation | 120 g | No | M | |
| Helly Hansen LifaLoft (Men's - Women's) | Testing | Synthetic | LifaLoft | 100 g | No | M | |
| Mammut Eigerjoch (Men's - Women's) | Testing | Synthetic | Polartec Alpha Direct | 95 g | No | M W | |
| Helly Hansen Lumines (Men's - Women's) | Unknown | Synthetic | PrimaLoft | ??? | No | M | |
| Haglofs V Series Mimic (Men's - Women's) | Unknown | Synthetic | Mimic Platinum Ultracluster Graphene | ??? | No | M W | |
| Black Diamond First Light (Men's - Women's) | Unknown | Synthetic | PrimaLoft Silver Active | 60 g | No | M W |
As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%. I explained why this happens here in this post of mine.
These are only approximate values assuming:
- you only have a shirt under and no shell over,
- during daily use (strolls, power walks etc at most - no high output activities),
- with enough wind to cause an umbrella to twist in your hand,
- and when it's dry out.
If you think you run warmer or colder than the average person, then shift temperature ranges accordingly.
Packing
Air is packable whereas the Atom and Proton LT aren't.
This makes Nano Air also a great choice for traveling.
The differences are:
Breathability
This makes up the single biggest downside of Atom LT.
Perfectly breathing FullRange insulation prevents you from overheating during any high output activity.
Which is why the Nano Air our top choice for that type of use.
Of all the Patagonia and Arcteryx jackets we reviewed, Nano Air is the most breathable and certainly lives up to the hype.
Atom LT, on the other hand, was released years before the Nano Air. So it isn't equipped with one of those advanced breathable active insulation pieces.
That's why its insulation can't keep up with the breathability of the cutting-edge jackets such as Nano Air or Proton LT.
But Atom LT comes with a well-known feature: Side fleece panels. Thanks to these panels under the arms, air can circulate much more and keeps you less sweaty when you're physically active.
This helps the Atom LT with its breathability, but undoubtedly not as much as that of the other two.
Also, all these jackets are DWR coated.
DWR is a coating.
It's basically sprayed on to the surface of these jackets as a finish. It stands for Durable Water Repellent - which means that water will be repelled under wet conditions instead of soaking into the fabric.
DWR also decreases dry time.
It's a good thing these jackets are coated in DWR, but pay attention to the fact that DWR is a coating - meaning that it will wear off over time.
Which is why you might want to invest in a DWR spray such as this one for after treatment.
As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%. I explained why this happens here in this post of mine.
Warmth & Weather Resistance
Side fleece panels of Atom LT become a disadvantage when it's cold, windy and/or rainy. They'll let some foul weather in.
However, in spite of these notable disadvantages, Atom LT still stays slightly warmer than the Nano Air because of the Air's somewhat "fragile" construction.
Absence of any side fleece panels simply doesn't cut it for Air in this manner.
In terms of warmth, Proton LT is positioned somewhere in between.
When it comes to weather resistance, on the other hand, relatively outdated outer fabric of Atom LT holds it back. Like Atom LT, Nano Air is also held back, but by its highly breathable face.
Proton LT seems to have found the sweet spot, and performs noticeably better than each of them.
Conclusion
In short:
- Getting the Nano Air (2019 version) would probably be a better decision if you're looking for an athletic piece to be used for high output activities ONLY.
- If you're going to use it in the neighborhood when it's cold out as well, then I'd recommend the Atom LT - but I'd also consider getting Proton LT as well (so read on).
- You can look at Proton LT as a more durable, comfortable and weather resistant but less breathable alternative to the Nano Air. If you'll be using the jacket both in the town when it's cold out AND during high output activities, Proton LT can really be one of your best choices.
I hope this post was helpful for you to learn more about the jacket(s) in your mind.
Feel free to ask me any questions or provide feedback and I'll be happy to respond in the comment section below.
Guide: Insulated & Shell Jackets
Start here:
Complete list:
Also see:
Thank you for reading!
Which of the 3 jackets would you recommend for cycle touring? I’m riding my bicycle ~20,000 miles the length of the America’s starting next summer and am looking for a nice warm riding jacket that will breathe well. Was leaning towards Proton or Nano Air. Any guidance?
Cheers,
Jeff