The Bags of Summer

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Outside magazine, April 1995

The Bags of Summer

For the kind season, bedding with just enough less of everything
By Douglas Gantenbein

Be overprepared. That’s the Boy Scout hypermotto that many campers mistakenly live by when it comes to bedding down in the summertime. I for one used to take my fat, zero-degree sleeping bag on every warm-season trip. I certainly never froze, but I was always uncomfortable. It was either get inside the sleeping bag and wake drenched in sweat or sleep on top of it in my pile
jacket and pants. I started to wonder why I brought the bag at all.

So I ultimately left it behind in favor of a summer sleeping bag. Summer bags are made specifically for kinder weather, and as a consequence they’re lighter, more packable, and less expensive than their cold-weather relatives. And nowadays they’re often designed for extra comfort: Summer’s the time to appreciate that today’s bags are being cut wider for more rolling room, have
soft linings that feel good against bare skin, and incorporate zipper designs that maximize ventilation. Yet most can still be cinched down to ward off the chill of 3 A.M. A summer bag will keep you warm even if the temperature dips to freezing.

The first thing you should understand when shopping for a summer bag–or any sleeping bag–is that the touted temperature ratings shouldn’t be taken as gospel. Those numbers are established by the manufacturers and may be useful for comparison, especially among different bags from one maker, but they’re sometimes optimistic. As a rule of thumb, choose a bag rated five to ten
degrees cooler than the lowest temperatures you expect to encounter. For most folks, such a bag will provide a sufficient reserve without being too hot; if you tend to “sleep cold,” however, seek out a bag that’s rated five degrees lower still.

Next you’ll need to choose between down and synthetic insulations, and with summer bags that can be tough: Because they have a relatively small amount of insulation, most summer bags, synthetic or down, weigh around two pounds. All pack pretty well. And for $150-$200 you can find excellent candidates in both camps.

Other things being equal, down bags drape more comfortably and are more durable. After even a summer or two of frequent use, synthetic insulations can start breaking apart and losing their “loft,” the quality that creates the dead-air space that insulates you. Down is much more resilient, and while almost any synthetic is superior to down when wet, few people should really
care: In 24 years of camping and climbing in the rainy Pacific Northwest, I’ve never been the victim of a soggy bag. Unless you’re a boater or sleep in a leaky tent, you shouldn’t weigh the wetness factor too heavily.

Still, synthetic bags deserve respect and consideration. Their warmth-to-weight ratios can rival those of down bags, and synthetic bags in general are somewhat less expensive. The best synthetics available include Primaloft, Micro-Loft, Lite Loft, and Polarguard HV, as well as some proprietary spinoffs; each has its own virtues and shortcomings, but generally, if the bag you
like is insulated with one of these materials, you can buy it confidently. If you decide on down, know that there’s variety here, too. Down insulations are rated according to “fill power,” the number of cubic inches an ounce of the stuff fills up. Down rated as “700-fill,” for example, has more loft and thus greater insulating ability than 500-fill down–and, other things being
equal, a bag made with it will be lighter and more expensive.

In shell materials, you’re no longer stuck with ripstop nylon. New, soft but tough microfiber fabrics feel good against the skin and are so densely woven that they effectively block wind and moisture while remaining breathable. DryLoft, a version of Gore-Tex made specifically for sleeping bags and insulated clothing, is also an excellent choice, though its weatherproofness may
be overkill in summer and it generally adds about $80 to the price. You’ll also want to feel inside the bag to make sure it’s lined with a material that you won’t mind against your skin. Most summer linings are designed to wick away moisture or reflect heat back into the bag.

This brings us to bag shape. Mummy bags have the smallest volume and the tightest fit, making it easier for your body to warm the inside and harder for cold air to find its way in. But they’re also more restrictive, and since these are summer bags, coldness isn’t always a big concern. “Barrel bags,” aka modified mummies, offer a bit more room, and semirectangular bags are even
wider (and heavier). I’ve reviewed bags with a variety of silhouettes.

A few finer considerations: Does the zipper open from both top and bottom, to give you ventilation options? Is there a roomy footbox that lets you wiggle your toes? What about a good-fitting hood, which is necessary if you plan to bed down in chillier climes? If you want to snuggle with a partner, look for a bag that can be zipped to a mate (unless noted, all of the models here

Here’s a selection of eight of the best summer bags, down or synthetic, that can be unstuffed and slid into.

MontBell Twilight
Value-seeking backpackers and bike tourists might consider the 40-degree Twilight ($109), especially if they’re worried about generating enough heat or letting in cool air. It’s a slim-cut mummy that fits even closer than most, thanks to a series of elastic loops that gently hug the bag to its occupant. They work–actually embracing a knees-up sleeper like me a little too
effectively. The proprietary synthetic fill employs a mix of thick fibers for durability and thin ones for warmth, and MontBell claims the insulation retains its loft better after multiple use than competing fills. The two-pound, two-ounce bag packs well.

Gold-Eck Husky 850
This is my favorite synthetic bag of the bunch, because its proprietary synthetic insulation is so downlike. The Austrian-made Husky ($160) is stuffed with fine, hollow fibers that give it a far nicer drape than most synthetic bags. It has a well-shaped hood, a ripstop, water-repellent nylon shell, and a quilted, cottonlike nylon liner. At just a hair over two pounds, the Husky is
light and packs well; as for the 35-degree rating, call it slightly conservative, even though the Gold-Eck cuts a barrel shape.

Moonstone Minima
Another worthy contender in a 30- to 45-degree bag is the feature-filled, mummy-shaped Minima (two pounds, one ounce; $170). Its Lite Loft insulation is thicker on top–the designers at Moonstone figure you’ll use a sleeping pad to insulate yourself from the cold ground. There’s also a yoke collar that sits over the shoulders to keep out drafts and a soft, smooth nylon lining that
wicks moisture. An ergonomic hood and two optional insulated liners make this an especially versatile bag: Add one of Moonstone’s down ($125) or Polarguard HV ($60) inserts and snug down the hood, and the Minima will keep you comfortable in sub-20-degree temperatures.

Expedition Trails Kodiak
The Kodiak ($223) is shaped less like a mummy than a cobra. The tight-fitting bag has gusseted shoulders and a ten-panel hood. It also zips down the front rather than the side, so you can easily sit up in the bag or even unzip it from the bottom, stick your feet out, and enjoy what amounts to a Micro-Loft robe. There’s a generous draft tube to keep warm air from finding its way
through the zipper and a handy accessory pocket sewn to the outside of the bag. Unfortunately, the Kodiak can’t be joined to another Kodiak, and it’s relatively bulky and heavy at three pounds.

The North Face Lightrider
The two-pound Lightrider may not weigh appreciably less than some synthetic bags, but it compresses down to nearly nothing in your pack and will keep you warm to about 35 degrees. Its 550-fill insulation is augmented by a slim mummy shape, which doesn’t let much air in or out (and doesn’t let you turn over so easily, either). I’m not a big fan of the nylon taffeta shell and
liner–they don’t feel quite as nice as some of the materials used on the other bags–but that’s a pretty small complaint. At $169 the Lightrider is a solid down summer bag at a good price.

Mountain Hardwear Crazy Legs Semi-Rectangular
Mountain Hardwear has gotten around the mummy-versus-rectangular shape dilemma with a bag that’s both. The Crazy Legs ($185) has a hybrid shape and elastic loops at the knees. But these loops aren’t meant to hug so much as to expand: Bend your knees or jackknife your legs under the covers, and the Crazy Legs will stretch to give you six more inches of room. The bag is insulated
with 550-fill down and seems fairly rated to 25 degrees. I found it comfortable and warm, if somewhat heavy at three pounds.

Marmot Moraine
The Moraine (two pounds, 11 ounces; $285) is as serious a bag as you want to make it. The base model is no slouch: Its barrel-shaped lid is luxuriously roomy, the 725-fill down makes the bag light and puffy, and the slinky microfiber shell

and liner feel like satin underwear against your skin. Two zippers let you adjust ventilation, and the bag can be unzipped flat to form a quilt. But if you want to extend the Moraine’s 20- to 30-degree rating, Marmot sells a matching hood ($51), or you can get the bag with a DryLoft shell ($90) if you often camp in wet conditions.

Western Mountaineering Badger
For its features and its temperature rating (25 degrees), the Badger is light at two pounds, seven ounces. With a generously insulated hood and a thick draft tube muffling the zipper, it’s the most hardcore of the down bags in this roundup. It’s cut somewhat more generously than a standard mummy, and its soft nylon taffeta lining (a close second to the Marmot’s) makes the bag hard
to get out of on a cool morning. The 700-plus-fill down gives the Badger plenty of loft and a promise of durability: It should last you a decade or more.

Douglas Gantenbein is a Bellevue, Washington-based freelancer who writes widely on the outdoors.

See also:

Essentials: The Pads to Pack

Where To Find It

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