Patagonia Nano Puff Pullover

By STEPHEN REGENOLD

The PrimaLoft-packed Nano Puff Pullover from Patagonia will not be available in stores until August 2009. But last month the company shipped me an early version of the lightweight coat to try out during a mountaineering trip in the Sierra Nevada Range.

Scrunch and squeeze this quilted coat down and it will compress inside its own chest pocket to create a grapefruit-size package that weighs less than a pound (10.3 ounces on my scale). But unfurl the top and it is a mid-weight insulating sweater/coat that is wind- and water-resistant and can be worn as a layer under a shell or alone as outerwear.

Last month, I snowshoed in the Sierra Nevada Mountains for more than 15 miles in the Nano Puff, trudging uphill with a heavy pack toward our 11,204-foot mountaineering objective. On the approach — between 7,000 and 9,000 feet on a 25-degree day — the coat was about perfect paired with a single, thin merino wool base layer underneath.

Later, in camp at night, I pulled my REI shell jacket over the Nano Puff, allowing the stuffed PrimaLoft insulation to trap heat and create a cocoon of warmth while eating dinner under the stars.

On the mountain the next day, I unzipped the Nano Puff’s chest for ventilation when the uphill work made me overheat. I rolled up the sleeves, elasticized cuffs gripping to bare skin. The coat’s shell fabric, made from recycled polyester, stopped wind as we worked higher onto the peak.

The minimal coat is missing a few essentials when worn as a piece of outerwear. There are no side pockets to warm the hands — something I missed when going glove-less. There’s a single chest pocket, but no inside pocket for little things. The half-zip chest is adequate for ventilation, but it is not as convenient as a full zipper for on-and-off.

Don’t expect to cook in the Nano Puff. It is only a moderately warm coat. Depending on the sun and wind — which trump temperature in many situations — the Nano Puff is good for use as outerwear to only about 20 degrees outdoors when you’re active (and maybe 35 degrees for standing around). In most situations, it will not serve as a substitute to a “belay jacket” or a down puffy the likes of Cloudveil’s Inversion Jacket or the Phantom Jacket by Mountain Hardwear.

Overall, the Nano Puff Pullover — available in a men’s and women’s version in August for $150 — is a nice addition to a mid-layer arsenal. It fits fine and packs small. The coat, though compromising on some features, is comfortable in the mountains, the woods, or for simply trekking around town.

—Stephen Regenold writes the weekly Gear Junkie Scoop for Outsidemag.com and TheGearJunkie.com.