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Sleeping Bags Explained

Baffled by baffles? Sleeping bag design ain't rocket science. Curl up with our pointers.

(Illustration by Steve Stankiewicz)
2004 Buyer's Guide : Sleeping Bags Explained

 •  While more expensive, a down sleeping bag will likely last two to three times longer than a synthetic sack, making goose fluff the economical long-term choice. And nothing beats down's softness or warmth-to-weight ratio. But keep your down dry—once wet, it offers zero insulation value.

 •  A hood adds tremendous warmth. So does a draft collar, which prevents heat loss around your neck. Look for a draft tube behind the zipper, too. And about zippers: One that's full length lets you ventilate on warm nights.

 •  Down's insulation capacity is measured in fill power—the volume, in cubic inches, occupied by one ounce of the material. Down measuring 600 to 650 fill is excellent quality; the very best stuff can be 900.

 •  Synthetic insulations, such as Polarguard Delta, PrimaLoft PL2, and DuPont Thermolite, won't compress as well as down but can be easily machine-washed and -dried.

 •  Manufacturers are pushing the limits of ultralight shell fabrics (some weigh less than an ounce per square yard). Most have a durable water-repellent coating. The latest trick? Eliminating stitching (and needle holes) by welding baffles to the shell.

 •  The classic mummy-shaped bag is best for heat retention and weight savings, but the tighter ones can be claustrophobic. Try before you buy. For mild conditions, consider a semi-rectangular bag, with room to thrash.

 •  Look for nice touches like a microsanded polyester to give the illusion of sleeping on silk. Sleeping-pad loops will prevent a 4 a.m. encounter with the cold tent floor.

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