How to Pick the Best Sleeping Bag for Your Next Camping Trip
When you’re new to backpacking and camping, it’s easy to get overwhelmed by all of the technical specifications involved in choosing your gear. Sleeping bags are no exception. To the untrained eye, a -40F rated, down-fill bag may look super similar to one with synthetic fill that’s rated for 35F. But those factors could make a huge difference with regards to your personal comfort and safety.
Here, we’ll decode the most important aspects of a sleeping bag—how warm the bag is, what it’s insulated with, and how it’s sized—to help you find one that makes the most sense for both your body as well as the season and environment where you'll be using your bag. Once you’ve made sense of the particulars, investing in the right sleeping bag (and sleeping pad) can make snoozing on the ground just as cozy as a night in a hotel room.
The most important consideration when picking a sleeping bag is how warm you'll be while asleep. Sleeping bags come with a temperature rating to let you know what air temperature that sleeping bag was designed for. Sleeping in a 10F bag when it’s 65F out? You’ll be sweating in minutes. Got a 40F bag and it’s only 20F out? Your teeth are going to be chattering all night. If you want to be comfortable, you’ll need to do your research.
In the past, sleeping bag manufacturers develop their own temperature ratings, and there was no good way to objectively compare the warmth of two sleeping bags made by different companies. In 2005, the European Norm (EN) 13537 was released as a standard for all sleeping bags sold in Europe that mandates scientific testing with a thermal manikin to determine an accurate temperature rating for every single bag. The result is a standardized temperature rating, making it easier for you to buy the sleeping bag you need.
It's important to note that women, on average, sleep about 12 degrees colder than men. Standardized temperature ratings account for this by differentiating between “lower limit” (men’s) and “comfort” (women’s) ratings. A women’s bag rated 25F will offer about the same amount of insulation as a men’s bag that’s rated 37F. Conversely, a men’s bag rated 25F will offer about the same amount of insulation as a women’s bag that’s rated 13F.
Down Versus Synthetic
The filling that gives sleeping bags their volume is also what allows them to trap your body heat and keep you warm. Two main types of fill are in use today: synthetic polyester fibers and natural down from geese or ducks. Both synthetic and down sleeping bags have their advantages. Synthetic bags retain their loft when wet and are easier on your budget, while down bags weigh less relative to their temperature ratings and compress to a smaller size.
The type of fill doesn’t affect the temperature rating of the bag, which means a 20F down bag will keep you just as warm as a 20F synthetic bag. The same applies to the quality of down used; a higher fill rating (down typically ranges from 500 to 900) merely provides a measure of how much loft one ounce of down provides. For that reason, a 20F bag made from 500-fill down will keep you just as warm as a 20F bag made from 900-fill down, but the higher-quality, 900-fill down bag will compress smaller and weigh less. Here, the choice you need to make is all about how much space you can afford (and load you can carry) when the bag is rolled up and stashed in your backpack.
Sleeping Bag Sizes
Sleeping bag sizing is more of an art than a science, but they generally come in three sizes: long, regular, and women’s. Long sleeping bags are designed for folks who are up to 6’6” tall; regular fits up to 6’; and women’s bags are sized for people 5’6” or shorter. To avoid feeling constricted, long bags will also tend to be wider at the shoulders relative to their length and women’s bags will tend to be wider at the hips.
Don’t limit yourself to the sleeping bag that matches your exact height, though. We recommend trying a few and selecting what's most comfortable. But be aware that if your sleeping bag is too large, you’ll be slightly colder, as all that extra space inside the bag is filled with air rather than insulation. And if a bag is too small, you’ll be cramped, uncomfortable, and (in some situations) also slightly colder, as a tight fit compresses the insulation, effectively reducing its loft and warmth. It’s also worth noting that long bags tend to both cost and weigh slightly more than their regular-sized counterparts.
Now that you know exactly what you need in a perfect sleeping bag, here are a few of our favorite examples. They'll all keep you warm, comfortable, and ready to tackle the next day’s adventures.
The North Face Furnace 20
The North Face, which makes full-body expedition down suits for the coldest environments on earth, has used the same technology to make the Furnace 20. This bag features a wider cut around the torso, making it less claustrophobic than other comparable sleeping bags. Like almost all sleeping bags, the zipper will try to catch on fabric as you zip and unzip the bag, but the built-in anti-snag tape and a bit of patience will help to keep this from happening.
Temperature rating: EN 20F
Fill type: 550-fill goose down
Weight: 2 lbs., 10 oz.
EMS Bantam 35/50
Most sleeping bags give you a few options to manage temperature, such as two-way zippers that let you stick your feet out or hoods that open up more to allow more ventilation. The Bantam 35/50 by Eastern Mountain Sports offers another option: one side is built with enough insulation to keep you warm when it’s 35 degrees out, and the other is built for 50-degree temperatures. By flipping the bag over, you can make sure you stay at a comfortable temperature even as the thermometer dips and rises through the night.
Temperature rating: 35F and 50F
Fill type: Poly Hollow Synthetic
Weight: 2 lbs.
To buy: ems.com, $119
Marmot Never Summer
The Marmot Never Summer is a great bag for when temperatures plunge below freezing. A good value choice compared to other 0F down bags, this one has a down-stuffed draft collar and multiple baffles in the hood to keep your head warm.
Temperature rating: EN -1.2F
Fill type: 650-fill duck down
Weight: 3 lbs., 1 oz.
To buy: rei.com, long also available, from $289
Mountain Hardwear Hyperlamina Torch
Instead of a zipper that runs down the entire length of the side, but the Hyperlamina Torch has a half-zipper that runs down the front. This helps minimize snags and improves the warmth of the bag, as zippers are typically weak spots with little to no insulation. This bag also utilizes one of the biggest advantages of synthetic insulation, which is that it doesn’t shift around. Down, on the other hand, is loose within the baffles. Additional insulation is strategically positioned in the sleeping bag to improve overall warmth (think: the lower core area and the feet).
Temperature rating: EN 3F
Fill type: Synthetic Thermal.Q
Weight: 3 lbs., 4 oz.
To buy: amazon.com; long also available, from $255
Eddie Bauer Kara Koram 0 StormDown
Like some of the other down sleeping bags on this list, Eddie Bauer has treated the down in their Kara Koram 0 StormDown with a hydrophobic coating. If down is completely soaked, it will clump together, eliminating its loft and insulating abilities. The hydrophobic coating reduces moisture absorption of individual down feathers and reduces drying time if they do get wet. When applied to incredibly lofty 850-fill down and protected by water resistant nylon, the result is a down sleeping bag that performs surprisingly well in damp conditions.
Temperature rating: 0F
Fill type: 850-fill down
Weight: 2 lbs., 12 oz.
To buy: eddiebauer.com; long also available, from $579
Nemo Nocturne 15
While many sleeping bags are cut in a tight mummy shape to improve the temperature rating, Nemo has instead opted to prioritize space and comfort. The Nocturne 15 features extra width throughout, but particularly near the shoulders and knees. If normal sleeping bags leave you feeling claustrophobic, the Nemo Nocturne may be your match.
Temperature rating: EN 15F
Fill type: 750-fill down
Weight: 2 lbs., 5 oz.
Big Agnes Encampment
Rolling off your sleeping pad and waking up on cold, hard ground is not how you want to start your day. Big Agnes has tackled this problem by building a sleeve into the sleeping bag itself so that no matter how much you toss and turn, your sleeping pad stays put. The Encampment also has a hood that fits more like the hood on a jacket rather than the hoods typically attached to sleeping bags, giving you more range of motion.
Temperature rating: 15F
Fill type: Insotect Hotstream Synthetic
Weight: 3 lbs., 4 oz.
The Marmot Atom is incredibly lightweight, and designed for summer adventures when you don’t want to be lugging around a huge sleeping bag. A second zipper lets you fold down the front of the bag, improving ventilation on hot and humid nights. The combination of a hydrophobic down coating and a water-resistant nylon shell keeps you warm, even if a summer shower manages to leak into your tent.
Temperature rating: EN 35.4F
Fill type: 800-fill goose down
Weight: 1 lb., 5 oz.
Kelty Cosmic Down 40
A no-frills sleeping bag, the Kelty Cosmic Down 40 offers all the advantages of down fill at a more accessible price point. It’s a great choice if you’re just getting into summer camping and don’t feel comfortable making a heavy investment.
Temperature rating: 40F
Fill type: 600-fill duck down
Weight: 1 lb., 12 oz.
To buy: amazon.com; long also available, from $120
Western Mountaineering Bison GWS
A temperature rating of -40F? The added zero is not a typo. If you never want to be cold again when camping in the winter, this bag is the real deal. The Bison GWS has a full 10 inches of lofted down, interlocking draft tubes running alongside the zipper to keep frigid air out, and Gore Windstopper fabric to keep cold wind from cutting through the sleeping bag and stealing precious heat. If you’re considering an expedition to the South Pole, the hefty price tag will be worth every penny.
Temperature rating: -40F
Fill type: 850-fill goose down
Weight: 4 lbs., 10 oz.
To buy: ems.com, $1,065
Enlightened Equipment Revelation
Modern quilts use the same high-quality materials as sleeping bags, but they’re less confining. Instead of wrapping around you and zipping up, they drape over your body and rely on a sleeping pad to keep your backside warm. Enlightened Equipment’s quilts are some of the best because they’re fully customizable in width, length, temperature rating, down type, color, and more. You're essentially getting a bespoke bag.
Temperature rating: 20F
Fill type: 850-fill down
Weight: 1 lb., 4 oz.
To buy: enlightenedequipment.com, $255
Big Agnes Big Creek 30
High-altitude mountaineers are known to share a single sleeping bag to save weight and share warmth, but you don’t need to be camped out at 26,000 feet to take advantage of this idea. The Big Creek 30 has room for two, with a zipper on each side to make getting in and out easy. Like all Big Agnes bags, this one features sleeping pad sleeves so your pad won’t shift out from under you while you sleep.
Temperature rating: 30F
Fill type: SL90 Synthetic
Weight: 5 lbs., 8 oz.
To buy: amazon.com, $240