Sleeping Bag Review: 4 Down Bags

Sleep warm, carry less with these 20-degree sacks.

Moonstone Lucid

Pure comfort is the payoff in this near-perfect three-season sack.

The Lucid is one of the best-fitting mummies we've ever tested. The cut is wide enough that I could read with my book tucked completely inside for warmth, but the carefully measured roll-around space didn't leave too much space to heat up. That--plus baffles overstuffed with 800-fill down--kept me warm while I wore just a single layer during three low-20s January nights in Idaho's Sawtooth Mountains. And when it gets colder, no worries. The hood closes down to a neat blowhole, and a fat draft tube seals the zipper. Nice touches: A wide strip of stiff nylon on the draft tube keeps the zipper from snagging, and independent hood and collar drawstrings make midnight adjustments easy. It's not the lightest bag in this test, but its all-around performance and great price make it the best deal.

Price: $260

Sizes: 2 lengths

Weight: 2 lbs. 2 oz.

Contact: (800) 390-3312; www.moonstone.com.

GoLite Feather

Get warmth, weight savings, and the fit you want.

When a March night in the Sawtooths dipped to 2°F, I figured I was in for a long, cold, sleepless evening. But inside this cocoon, I had only to add a second layer on top of long underwear and a balaclava to stay warm. Why the great warmth-to-weight ratio? Three essentials: Lofty 800-fill down; a hood that cinches cleanly around the face to trap heat; and an efficient cut that's just big enough to allow you to change clothes inside (for a little more space, get the regular width instead of the trim). Plus, the highly compressible Pertex Quantum shell repels drafts and condensation. Side sleepers will like the short chest zip, as it keeps drawcords off your face--but it also limits venting. Stuffiness is mitigated by a nifty self-sealing footbox baffle, which lets you cool your feet without zipper fuss. The stuff sack drawcord blew out early, a bummer at this price.

Price: $300

Sizes: 3 lengths, trim and regular widths

Weight: 1 lb. 14 oz. (trim).

Contact: (888) 546-5483; www.golite.com

Feathered Friends Swallow UL Nylon

Choose from numerous shells and lengths to suit your conditions, budget, and height.

Want custom-bag options in a high-quality down mummy, but without the exorbitant custom fees? Like other Feathered Friends bags, the Swallow is available with an Epic, eVent, or Pertex Quantum shell for only $50 to $85 extra. (These materials are all highly weather-resistant, but have different levels of waterproofing and breathability.) The Swallow also comes in four lengths, but the girth favors thin hikers. I found it snug at the waist, and couldn't change clothes easily inside. The silver lining is super insulating efficiency; in the low 20s, I had to strip down to a single layer to avoid overheating. Featurewise, this full-length zip was Best of Show: It always operated cleanly, and double snaps prevented it from sliding open even a fraction of an inch.

Price: $286 (standard nylon shell)

Sizes: 4 lengths

Weight: 1 lb. 15 oz.

Contact: (206) 292-6292; www.featheredfriends.com

Big Agnes Zirkel

Big guys stretch out: This roomy, inexpensive bag won't cramp your style.

With Big Agnes's trademark design--a sleeve for your sleeping pad instead of insulation on the bag's bottom--the Zirkel manages to deliver the test's widest cut while still tipping the scales at a very competitive 2 pounds. And there's barely a tradeoff in warmth. On a night near freezing in the North Cascades, I slept comfortably outside my tent, even with an icy breeze blowing off the nearby snowfields. The spacious cut is best for bigger folks; my compact, 5'8" frame had lots of wiggle room in the regular. The proprietary nylon shell repels moisture well enough for typical tent condensation. But down quality isn't as high as the other bags; the 725-fill feathers lost some loft after several months of use. And side sleepers beware: The integrated pad/bag design means the hood doesn't roll with you.

Price: $229

Sizes: 2 lengths

Weight: 2 lbs. (877) 554-8975; www.bigagnes.com.