Winter Sleeping Bag
Mountain Hardwear Phantom 0

$650, 2 lbs. 9 oz. (regular, 72-inch)

Sizes: short, regular, long

The forecast made me sit up and wonder: Will my bag be warm enough? For the three nights in late December that I planned to spend in a tent in Idaho’s Boise Mountains, lows would drop into single digits Fahrenheit—below the “comfort” rating and approaching the “limit” rating of my Mountain Hardwear Phantom 0. And this on my maiden voyage with the bag; I had not used it yet. As it turned out, I had nothing to worry about with this extraordinarily warm and packable, ultralight winter sleeping bag.

I found the Phantom 0 impressively warm even on a night that plunged to 3° F—10 degrees below its EN comfort rating of 13F/-11C and near its 0F/-18C limit rating. And yet, I slumbered comfortably wearing only midweight top and bottom layers and warm socks, adding a wool hat only during the night. I have long observed, as a warm sleeper rather than a cold sleeper, that only the highest-quality down bags will keep me warm down to their temp rating. (I didn’t have nights in this bag anywhere near the Phantom 0’s bone marrow-thickening extreme rating of -38F/-39C.)

One defining metric tells much of the Phantom 0’s story: A bountiful 30 ounces of 850-fill-power goose down constitutes three-fourths of the bag’s total weight. Stuffed fat with nearly the highest-quality down on the market (there are a few bag models with down rated at 900-fill) explains this bag’s two major advantages: a sky-high warmth-to-weight ratioandexcellent packability.(The down quality also partly explains the price.) Even after being compressed for hours, this fat bag lofts up quickly.

Not only does the Phantom 0 have a greater fill weight and lower total weight than many bags in this temperature-rating category, but at about 2.5 pounds, it weighsno more than many 600-fill down bags that carry an EN limit rating of 20F. Plus, it packs down to 8.25 ins./21cm x 16.5 ins./42cm. Sold with a compression stuff sackincluded (3.5 oz.), the Phantom 0 compresses as compactly as some 20-degree down and synthetic bags. It bears noting the obvious point that I’m drawing comparisons between the Phantom 0 and bags that are in an entirely different class for warmth.

Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-guides to classic backpacking trips. Click here to learn how I can help you plan your next trip.

Mountain Hardwear Phantom 0 sleeping bag.
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