Proton & Atom LT vs Nano Air: Key Points (May 2020)

Proton LT would be my overall top pick, whereas the Nano Air would be my top pick for high output activities.

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.

But I'll still give you what you want and compare both of them.

As some of you know, I compared the synthetic insulated jackets of the two of most well-known manufacturers: Patagonia and Arcteryx.

In this post, I'll include the related part of that article as well.

But right before we get to it...

Lowest temperatures you can wear these jackets without feeling uncomfortably cold are...

	°F / °C	Insulation
Arc'teryx LEAF Cold WX Parka SVX (Men's)	-40/-40	Down
Arc'teryx Ceres SV (Men's)	-15/-26	Down	Read Review
Arc'teryx Firebee AR (Men's - Women's)	-10/-23	Down	Read Review
Arc'teryx Dually Belay Parka (Men's)	-7/-22	Synthetic
Arc'teryx Thorsen Parka (Men's)	-7/-22	Down	Read Review
Patagonia Frozen Range Parka (Men's - Women's)	-6/-21	Down	Read Review
Arc'teryx Centrale (Women's)	-5/-20	Down	Read Review
Arc'teryx Cerium SV (Men's - Women's)	-5/-20	Down	Read Review
Arc'teryx Therme Parka (Men's)	-2/-19	Down	Read Review
Patagonia City Storm Parka (Men's - Women's)	0/-18	Down	Read Review
Arc'teryx Camosun Parka (Men's)	0/-18	Down	Read Review
Arc'teryx Fission SV (Men's - Women's)	3/-16	Synthetic
Patagonia Tres 3-in-1 Parka (Men's - Women's)	3/-16	Down	Read Review
Arc'teryx Patera Parka (Women's)	5/-15	Down	Read Review
Arc'teryx Kappa (Men's)	7/-14	Synthetic
Patagonia Macro Puff (Men's - Women's)	8/-13	Synthetic
Arc'teryx Thorium AR (Men's - Women's)	8/-13	Down	Read Review
Arc'teryx Atom AR (Men's - Women's)	10/-12	Synthetic	Read Review
Patagonia Vosque 3-in-1 Parka (Women's)	10/-12	Down	Read Review
Patagonia Jackson Glacier (Men's - Women's)	12/-11	Down	Read Review
Patagonia Hi Loft Down (Men's - Women's)	14/-10	Down	Read Review
Arc'teryx Magnus Coat (Men's)	14/-10	Down
Arc'teryx Cerium LT (Men's - Women's)	17/-8	Down	Read Review
Patagonia Down Sweater (Men's - Women's)	19/-7	Down	Read Review
Arc'teryx Nuclei FL (Men's - Women's)	19/-7	Synthetic	Read Review
Arc'teryx Atom LT (Men's - Women's)	23/-5	Synthetic	Read Review
Arc'teryx Proton LT (Men's - Women's)	24/-4	Synthetic	Read Review
Patagonia Micro Puff (Men's - Women's)	24/-4	Synthetic	Read Review
Patagonia Silent Down (Men's - Women's)	26/-3	Down
Patagonia Nano Puff (Men's - Women's)	28/-2	Synthetic	Read Review
Patagonia Nano Air (Men's - Women's)	32/0	Synthetic	Read Review
Arc'teryx Cerium SL (Men's - Women's)	40/5	Down	Read Review
Arc'teryx Proton FL (Men's - Women's)	43/6	Synthetic	Read Review
Arc'teryx Atom SL (Men's - Women's)	50/10	Synthetic	Read Review

Read more about this chart here in my Insulated Outerwear Temperature Ratings Guide.

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.

Also check out my Arc'teryx Favorites and my Patagonia Favorites.

If you're interested in down jackets only, see my Best Down Jackets post.

Nano Air received an update in Fall 2019. Check out this post of mine if you want to see what's new.

On Patagonia's site, this is the new hoody.

Now back to the comparison chart:

	Arcteryx Proton LT Hoody Read Review	Patagonia Nano Air Hoody Read Review	Arcteryx Atom LT Hoody Read Review
MSRP	299 USD	299 USD	259 USD
Overall Score	86/100	80/100	76/100
	Arcteryx Proton LT Hoody	Patagonia Nano Air Hoody	Arcteryx Atom LT Hoody
Bottom line	Best choice for those who'll be using the jacket both in the town & during high output activities	Best one if you'll be using it for high output activities only	Top alternative to Proton LT
	Arcteryx Proton LT Hoody	Patagonia Nano Air Hoody	Arcteryx Atom LT Hoody
Warmth Comfort Weather & Abrasion Resistance Breathability Style	7/10 10/10 7/10 9/10 10/10	6/10 9/10 6/10 10/10 9/10	8/10 8/10 6/10 7/10 9/10
	Arcteryx Proton LT Hoody	Patagonia Nano Air Hoody	Arcteryx Atom LT Hoody
Weight	375 g (13.2 oz)	346 g (12.2 oz)	415 g (14.6 oz)
Insulation Materials	65g Coreloft Continuous	60g FullRange insulation	60 g/m2 Coreloft
	Arcteryx Proton LT Hoody	Patagonia Nano Air Hoody	Arcteryx Atom LT Hoody
Face Fabric	92% Nylon, 8% Elastane	Nylon ripstop (33D)	20D Nylon Tyono/ Polartec Power Stretch
Cell	#Note: All face fabrics are DWR (durable water repellent) applied.

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.

Breathability is the most important factor to consider when looking for an "athletic" use jacket

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.

What is DWR by the way?

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.