Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Tuesday, February 28, 2017

GEAR REVIEW: Patagonia Nano-Air Jacket

The basic issue, for me, is the jacket’s active exertion comfort range, by itself, occurs at colder temperatures than I normally encounter. On many occasions, especially sunny, calm, cool (25-35F) conditions, the jacket simply got too hot so I had to take it off.

By Will Rietveld

The concept started with the introduction of Polartec Alpha – breathable insulation claimed to maintain warmth and comfort while actively exercising. Soon after the introduction many manufacturers offered breathable insulated jackets. Although Patagonia uses their proprietary FullRange Insulation rather than Polartec Alpha in the Nano-Air Jacket, the functionality is basically the same, and Patagonia does a great job with the implementation.

Patagonia men’s Nano-Air Jacket in “Underwater Blue”.

The Nano-Air, and other jackets of this type, are claimed to be a jacket that you never have to repeatedly put on and take off to stay comfortable in varying conditions, and one that permits the user to stay comfortable no matter what level of activity. That’s a “lofty” claim, so I decided to try one out to see how it actually performs. Actually, if the claims are even somewhat real, that would be a good improvement.

Specifications and Features

Patagonia (www.patagonia.com)
Men’s Nano-Air Jacket
Shell and Lining
Shell is 1.3 oz/sq yd 20-denier nylon ripstop with DWR, lining is 2 oz/sq yd 50-denier plain weave nylon with DWR; both have 2-way stretch
60-gram FullRange polyester, 40 CFM
Measured weight men’s Large 13.2 oz; mfr specification 12.5 oz for size Medium
Full-height front zipper with storm flap behind, 2 zippered handwarmer pockets, 1 zippered chest pocket, elastic cuffs, hem drawcord with 2 adjustors
Athletic fit with set-in sleeves, “unlimited range of motion”


Front View. The Nano-Air has an athletic fit, meaning close to body. The sleeves are extra long and trim, and the body extends below the waist. The full-height zipper is not the water-resistant type.

Back View: The jacket is sized so it can be worn over a heavier baselayer or fleece pullover.

Hand Pockets. Two “handwarmer” pockets are actually lined with the shell and lining fabrics. Both are very soft so they feel warm. The pockets are large enough to store gloves.

Chest Pocket and Shell Fabric. The chest pocket is large enough to store a compact camera or cell phone. There is no port to route ear buds. This photo also give a good closeup of the shell fabric, which has a very soft/pleasant feel. It’s ripstop nylon for durability that has been brushed for softness and has a DWR treatment.

Hem Drawcord and Lining Fabric. The hem drawcord has two adjustors (one shown) for sealing the bottom of the jacket. The lining is brushed plain weave nylon with a DRW treatment. Both shell and lining fabrics have two-way stretch.

Underarm. Brick quilting in the side panels, plus articulated patterning and other quilting details improve the jacket’s shape and durability.



I tested the Patagonia Nano-Air Jacket on a total of 11 trips that included backcountry skiing, snowshoeing, cross-country skiing, snow walking, and two multi-day ski-in trips to a mountain cabin.

Here are my fit/feel/ergonomic observations from testing:
  • The jacket is incredibly soft and supple, and has a stretchy feel.
  • The fit is excellent and true to size.
  • The back covers my butt.
  • There is room inside for some layering if desired.
  • The fit around my neck is loose (see the first photo under Description).
  • It has wonderful articulation and is very comfortable to wear.
  • The hand pockets are located high, above a backpack hipbelt.
  • Love the longer sleeves. 

Both the shell and lining have a good DWR treatment, which causes water to bead up and roll off, and prevent snow from sticking.

The brushed nylon fabric is easy to stain around the collar, but it’s easy to clean just that area.

My observations on temperature regulation and comfort in high-exertion activities are a mixed bag:
  • For me, the jacket performed best over a thin baselayer to get maximum benefit from its breathability.
  • Adjusting ventilation by opening/closing the front zipper, or tightening/loosening the hem drawcord are more effective for temperature regulation than jacket breathable insulation and fabrics.
  • The aforementioned combination of ventilation and breathability factors are sufficiently effective during active exertion only in cold or very cool conditions, specifically below 25F, overcast, and breezy/windy. Some combination of those factors is required for comfort, otherwise the jacket is too hot to wear comfortably.
  • On several cold days (below 15F) the jacket performed wonderfully with the front zipper closed.
  • However, on many occasions (not cool, overcast, or breezy enough), the jacket simply got too hot, even with the front zipper open, and I had to take it off.
  • As claimed, donning a shell over the jacket in really cold/windy conditions adds a lot of warmth.
  • When I stop to rest, the jacket dries out quickly, and I get chilly if I don’t donn a shell over it.



The basic issue, for me, is the jacket’s active exertion comfort range, by itself, occurs at colder temperatures than I normally encounter. On many occasions, especially sunny, calm, cool (25-35F) conditions, the jacket simply got too hot so I had to take it off.

I do agree that the jacket’s fabrics and insulation help to extend the comfort period, but a larger amount of temperature regulation is accomplished by simply opening or closing the front zipper.  I find the same to be true when I test waterproof/breathable rain shells – fabric breathability helps, but ventilation is the main contributor to comfort.

It appears, for me, that a lighter weight breathable jacket is needed, such as the Patagonia Nano-Air Light Hybrid Jacket, to accomplish the “keep it on” goal for high exertion sports in cool and cold weather. I can always don a shell over the lighter insulation layer if I get too chilly.

For light or moderate exertion in cool temperatures, like a walking pace on flatter ground, the Nano-Air performs well; it’s a matter of consistent weather conditions and activity level. However, how often does that happen? If the sun comes out, or a hill comes up, or the wind stops, its time to open the front zipper to regulate temperature, the same as any other jacket.

The bottom line from my testing is the Nano-Air Jacket effectively regulates temperature in cold weather active endeavors, but its too much insulation (for me) to wear continuously in active cool weather sports. The latter is more common in my situation, so the Nano-Air Jacket is too much insulation if the goal is to “keep it on”. I believe a more functional and versatile option would be to go with a lighter breathable insulation garment, like the new Patagonia Nano-Air Light Hybrid Jacket and don a highly breathable shell over it (such as the new Patagonia Airshed Pullover), as needed to maintain comfort. A combination of those layers, plus the huge ventilation benefits from simply adjusting the zipper(s) should perform well.


  1. I found similar results but in cool/wet conditions I like it for an "in-camp" puffy layer in place of a down jacket. Most of the time I use my Nano-Air as a very comfortable cold weather "in-town" jacket.

  2. Thanks for your comment Gerry. My testing was in the wintertime, so its is pretty humid in the mornings, but not wet. Next I want to test the lighter weight Patagonia Nano-Air Light Hybrid Jacket to see if it is a better match for the temperature/wind/sky conditions I most frequently encounter. I will use it in combination with the new Patagonia Airshed Pullover, which is a windshirt with much higher airflow than a conventional windshirt.


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