Testing the Versatility of Patagonia’s Nano-Air Jacket

For years, a war’s been raging in the performance outerwear market: breathability versus warmth, stretchability and comfort versus waterproofness. The result is that, ever since polyester came along to challenge the waxed canvas that first kept rain off of soldiers in WWII, outerwear has been getting lighter while also performing better — to the benefit of consumers and coat racks alike.

Stick your nose in the closet of an ultralight hiker and you’ll see: from “TurboDown” technology to under-arm vents to whatever “PrimaLoft” is, manufacturers have been obsessively designing and redesigning those few millimeters of fabric between you and the elements in the pursuit of one space-aged garment for all seasons and reasons. Last year Polartec introduced the future of activewear insulation with their Alpha, which they called the “first high-performance fabric to materialize the concept of active insulation” — insulation that transfers sweat out when you’re hot and keeps heat in when you’re cold. This year Patagonia released their own paradox in outerwear, a mid-layer jacket called the Nano-Air ($249) made from a new form of insulation called FullRange by Toray.

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For the shoulder seasons, or during “stop-and-go” activity high in the mountains, the Nano-Air jacket is meant to be a layer you don’t have to remove. This means that on a mountain ridge the jacket is breathable and flexible enough for a climber during a morning ascent, but insulated enough to keep the same climber warm later during a shady repel. The nylon jacket is meant to be porous to let out water vapor while you sweat, sealed with durable water repellent finish for brief rain showers and quick drying for when you do manage to sweat through it or lean against melting ice. That’s a lot of bases for one garment to cover, and the question quickly becomes whether it can do them all well.

Fresh off the rack, the most noticeable aspect of the Nano-Air is its softness. The nylon ripstop shell, 60-g FullRange Insulation and plain-weave liner combined only puff to about a quarter of an inch, but the material is designed to stretch easily in any direction for active use, resulting in an airy, malleable jacket with a marshmallow feel, like a puffy down jacket on a diet. It’s not waterproof enough to grab for a rainstorm, but for most chilly nights in the fall and spring (three-season in the southern states) you can take it out without much thought to the highs and lows of the day.

A QUICK PRIMER ON BREATHABILITY AND WATERPROOFNESS

Wet clothing is less breathable, so the first step in increasing breathability is finishing the jacket with DWR (durable water repellent), typically a fluoropolymer-based spray that increases the surface tension of water to make a fabric more hydrophobic. Instead of spreading and seeping into your nylon outer shell, the water droplets stays more spherical and easily roll off the garment. But how effective is it? Marmot, for example, guarantees that water will roll off at least 80 percent of a DWR-coated jacket’s surface, even after 20 washes. After heavy use and a lot of washes, DWR can be reapplied via spray-on or wash-in treatments.

As for breathability, or “air permeability” (breathability also refers to water vapor permeability), Patagonia rates the Nano-Air at 40 CFM, which means 40 cubic feet of air can pass through 1 square foot of the jacket in 1 minute at a pressure differential equal to a wind speed of 30 mph — which means exactly nothing to most people. These ratings are measured using the Frazier Air Permeability Test, and, as a guide, your traditional fleece rates at 200 CFM (a lot of wind passes through it), while a windproof garment drops down near 0 CFM (hardly any wind passes through it). As for breathability while you sweat, water vapor permeability tests carry names like the “upright cup test”, “inverted cup test” and “sweating hot plate test”, and, according to REI, “No universally accepted standard for fabric breathability exists.” So basically, you can compare garment to garment in the same brand, but there’s no real way to compare across brands.

Performance advantages aside, the jacket is damn comfortable. It falls under Patagonia’s slim-fit criteria, which means it fits comfortably over a base layer but is tight enough to tuck underneath a waterproof shell without bunching. For the more casual city dweller, this simply means you won’t look like Randy from Randy from A Christmas Story when you come in out of the cold — and that you’re at risk for being that guy at work who leaves his jacket on all day, simply because you forgot you were wearing it.

For belonging to a performance apparel sector notoriously overzealous with pockets, straps, velcro and adjustable everything, the Nano-Air cuts the drama where it counts. The wrists keep out a draft with elastic while the waistline can be adjusted by a hidden, low-profile cord. There’s no interior pocket breast pocket, which is unfortunate if you want to look like Don Draper when you reach for a pack of smokes, but a front zippered breast pocket keeps valuables close at hand, while two comfortable, hand-warming pockets replace the need for gloves on a chilly night and provide a good storage spot for a lightweight waterproof pullover while out on the mountain.

The Nano-Air represents the future of protective outwear: a mixed bag of breathability, temperature regulation and comfort. Sure, there are limitations: it doesn’t work as a sole garment for true wintry conditions or even just stiff autumn wind, as its breathability allows the wind and extreme cold cut right through the jacket. But the weight and volume mean you can throw on an outer shell and still wear a slimmer jacket than your average overcoat. Expect every major outfitter to come out with their own version of apparel for “stop and go” expeditions (or stopping on a cold sidewalk to wipe your feet before going into a heated Whole Foods) in the coming seasons. This step forward, minimizing layering by having one extremely versatile layer, is the goal of performance clothing, in which (ideally) one garment will keep you at a comfortable 72 degrees with an optional margarita blender stowed in a back pocket. In fact, for mid-40 to mid-60 weather, minus full waterproofing and those tiny drink umbrellas, we just arrived.

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