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