The Best Backpacking Sleeping Bag Review
What is the best 3-season sleeping bag for backpacking? We chose bags rated between 20-35 degrees F and felt each of the bags offered unique characteristics that different users might find valuable. We've evaluated all-around performance, weight, packed size, comfort, value, and solid blends of the aforementioned traits. We tested the latest round of bags in the backpacking paradise of California's Sierra Nevada mountains, with extended trips on the John Muir trail and throughout the Washington Coast and Cascade Mountains. Overnight temperatures ranged from 12-65F. Each bag endured a series of tests that measured its performance in a variety of metrics. Keep reading to find out which bags came out on top!
Read the full review below >
Test Results and Ratings
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Analysis and Award Winners
If we could only have one sleeping bag for backpacking and 3-season camping, it would be the Western Mountaineering MegaLite. The MegaLite was among the lightest and most compressible sleeping bags in our review (and on the market); weighing in at half the weight of several bags we tested, it still offers roomy enough dimensions to be comfortable for car camping or for side and tummy sleepers to enjoy on extended outings. The materials are top notch and felt the best against our skin among any bag in we tested. The icing on the cake is Western Mountaineering is a small California-based company that manufactures all of its sleeping bags and garments in the USA. Plain and simple, the MegaLite is a pretty rad bag. From single overnights to the John Muir Trail, this contender is among the most versatile bags in our review, thanks to its weight and dimensions. It's worth noting that its only two ounces heavier than our top pick for light and fast long-distance trips, but offers a full-length zipper, as well as more internal space.
Spacious and comfortable cut
Extremely light weight
Among the most compressible bags in our review
Made in the USA
Best feeling fabric in our review
Included stuff sack is a little big and doesn't compress it as small as it otherwise could be
The Marmot Hydrogen wins our overall "best value" award, as it offers a superb balance of quality, low weight, packability, and performance versus cost. The Hydrogen isn't the best price pointed bag, as the $150 Kelty Cosmic Down wins in that category. However, for a little more than $300, the the Marmot Hydrogen is a stand-out sleeping bag, offering several of the same materials, specs, and high quality 800+ down-fill that our other award winners, such as the Western Mountaineering MegaLite ($470) and Sea to Summit Spark III ($440) offer. The Hydrogen is also quite comparable in weight and packed size, but is $100 less.
One of the lighter and most compact sleeping bags in our review
Super high-quality bag for the price
Great hood design
Second short zipper is great for venting and getting into the bag
The affordable, yet reasonably lightweight and compressible Kelty Cosmic Down 20 takes our Best Buy Award. While hardly an overall top performer, this is the best down bag we've ever seen by a significant margin, especially for its $150 price. Cold sleepers and backpackers who frequently extend their three-season trips into lower temperatures will want something warmer, but everyone else on a budget should consider the Cosmic Down 20 (and pocket the several hundred dollar savings). This bag is far more durable and compressible than its similarly priced synthetic insulated counterparts and offers beginning or budget-conscious backpackers an exceptional value. If you are backpacking in warm summer conditions and want to shave a few more ounces, check out the Kelty Cosmic Down 40.
Great value bag
Hard to find a less expensive 600+ fill down bag
Lighter and more compact than most bags in its price range
Heaviest traditionally designed down bag we tested
Not as warm as other 20 degree bags
Roomy cut is amost too roomy
The Western Mountaineering UltraLite is an extremely warm bag that was by far the warmest in our review, while remaining among the lightest and most compressible. This award winner might just be a little too warm for most people to use for 3-season backpacking, but for cold sleepers or colder than average conditions, the Western Mountaineering UltraLite is tough to beat.
Warmest bag in our review
Lightest bag by far with its temperature rating (and even lighter than several 30F bags)
Great no-catch zipper design
Excellent compressed size
Very warm for mid-summer
Weak velcro closure for draft collar
Slightly on the tight side dimensionally
The Mountain Hardwear HyperLamina Spark 35 is our top pick for the best bag in wet conditions. During our water saturating testing, the Spark 35, like other synthetic-fill bags, dried in roughly 20% of the time as treated water-resistant down, making it a much more ideal bag for wet conditions. However, what truly sets the Spark 35 apart from most other synthetic bags is how incredibly small it packs down and how lightweight it is (1 l b 12 ozs). It's lighter and more compressible than several down bags we tested and it even offers roomier than average dimensions. All of our testers loved its half-length center zipper that still allowed plenty of ventilation on warm nights; it was also just plain easier to use. If you're looking for a synthetic bag, a company that respects ethical animal rights, or you have allergies to down and want one of the highest performing synthetic bags out there, the Spark is your bag.
Incredibly small packed size that was even smaller than several down models
One of the lighest synthetic bags out there
Center half-zipper is awesome
Cozy feeling interior fabric
Synthetic insulation isn't super long lasting
A little on the colder side of 35° bags
If you're on a trip where weight and space are your number one priority, but you need something more significant than an ultralight quilt, the Sea to Summit Spark III is hard to beat. This one pound 6 ounce bag is plenty warm enough for nearly any 3-season backpacking trip or summer alpine climbing trip (and it carries a legit OutdoorGearLab tested rating for 25 F). The Spark III packs down the smallest of any bag in our review, easily fitting into the corner of your pack; it won't remind you it's there until you crawl in for a well-deserved good night's sleep. The Spark Sp III is a high quality, super light-weight, traditional mummy style sleeping bag. It is smartly styled with the lightest 10D shell fabric in our review, 850+ Ultra Dry Down, and a mere 1/3 length side zip keep the weight to an absolute minimum.
Lightest weight and smallest packed size of any sleeping bag we tested
Interior fabric feels great against your skin
Enough shoulder room to wear at least a light puffy on colder nights
Is a true 25F bag that felt warmer than some 20F bags we tested
Tighter interior dimensions might feel a little cramped for some people
A little on the expensive side
The Nemo Salsa 30 wins our OutdoorGearLab Top Pick Award for being the most comfortable sleeping bag for backpacking. While the Sierra Designs Backcountry Bed 600 3-Season was a strong contender and it remains a cool and unique option, our review-team's real world testing and side-by-side comparisons determined that the Salsa was the winner. Our tummy and side sleepers just plain liked the Salsa's stretchy stitching and spacious "spoon" shaped design better. That, coupled with the Salsa weight (2lbs 1 oz, compared to the Backcountry Bed's 3lbs 1 oz), spells out true comfort. While it isn't the lightest bag we've ever tested, it remains respectable, especially considering its spacious cut. It still packs down roughly a third smaller than the Backcountry Bed 600.
One of the most comfortable bags in our review
Best bag for side and tummy sleepers
Great price for a down bag
Above average packability
Included stuff sack is too big and didn't do a good job at compressing the bag
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The Sleeping Bag: Your Most Important Insulating Layer
Your sleeping bag is likely the most important insulating layer that is carried on any wilderness excursion. Sleeping bags provide a better warmth-to-weight ratio than anything else in your pack. Investing in a quality sleeping bag that is suited to your needs will help you get a more comfortable night's sleep, save weight and space in your pack, and keep you warm when the temperatures start to drop. Sleeping bags are also the bed of choice for car campers, travelers, and couch surfers. This review focuses primarily on sleeping bags intended for backpacking. However, several of the bags proved to be well-suited for car camping, summer-time mountaineering, and late spring ski-touring. They tagged along on several road trips throughout our testing too.
We updated our existing review to include several new, innovative, and popular models and styles and compared them to previous award winners.
Choosing the Right Bag
We considered over 100 bags and took many painstaking hours to select the ones included in our review; in the end, we picked bags that we liked for different reasons. Our review includes a wide range of 3-season backpacking oriented sleeping bags from incredibly light and compact down bags, to some high performance synthetic bags, to a handful of bags with unique designs that offer exceptional comfort. We've also included a few budget-friendly down sleeping bags and reliable synthetic sleeping bags.
First, carefully consider the most common application of your sleeping bag. Yes, these are all backpacking oriented bags rated from 20-35F, but some bags are more versatile regarding where and when you use them, while others are best suited for specific conditions or trip objectives; some will also offer particular advantages when used under the right circumstances. If on a budget, try to avoid skimping on quality; look for a bag that balances warmth, weight, and versatility. If possible, consider two bags, a lower-priced sleeping bag for car camping/campground camping and a lightweight bag for backpacking and mountaineering.
You don't necessarily need to buy a 20F bag for a future trip that you might go on one day. Instead, buy a bag for the type of trip you most frequently go on. For the occasional colder trip, just plan to wear more layers. This will save you from carrying a bunch of necessary weight over time and it means you wont overheat on a majority of your trips.
To figure out what characteristics you should be prioritizing, you should reflect on what types of trips you enjoy and the types of conditions you are most likely to encounter. Do you frequently backpack in wet conditions on say, coastal hikes? Where a quick drying synthetic bag is best? Or do you embark on long-distance journeys where weight and pack space are at a premium? Are you someone who simply hates sleeping on their back or wants a little more leg room?
Criteria For Evaluation
We rated each bag on its warmth, weight, packed size, features, and versatility.
Check out the chart below to see where each bag landed on the Overall Performance metric.
Warmth is basically equal to the amount of loft in a bag, measured as the thickness of the insulation between you and the external environment. With the exception of very loose bags, more volume of insulation (not necessarily weight) basically equals more warmth.
Fit is the next most important factor in determining warmth. Bags that are too tight or too short won't allow the insulation to loft properly and as result, will feel colder where you are pressed against certain areas. Similarly, a bag that's too large will have drafty dead air spaces that make the bag thermally inefficient, even though it may have enough loft for the conditions.
Some bags tested here, such as the Western Mountaineering UltraLite and the Sea to Summit Spark Spark III have tighter interior dimensions, resulting in slimmer cuts; even most broad shouldered folks can at least wear a lightweight jacket while sleeping inside those bags. The rest of the bags we reviewed are wider and nearly everyone could wear a mid-weight jacket or more to boost insulation on colder nights. It's worth noting that Western Mountaineering sleeping bags are available in multiple lengths and widths, which is a huge advantage because you can get a bag that fits your body well. Look at the foot, hip, and shoulder circumference to compare dimensions for unisex bags. We've included these measurements in the specification tables found in each review when available from the manufacturers.
The backpacking sleeping bags that we found to be the warmest (for their respective temperature rating) were the high-quality down bags from Western Mountaineering, the Western Mountaineering MegaLite and the Western Mountaineering Ultralite. Both of these bags have 850+ fill power down and plenty of it; 13 and 16 ounces respectively. The MegaLite is a 30F bag and is roomier than the Ultralite, which is a 20F model. The least warmest bag in this review is the lightweight Mountain Hardwear HyperLamina Spark 35. The thinner insulation offers less protection from the elements and the lack of a draft tube allows more cold air inside the bag, leaving the sleeper less toasty than in the other bags. That said, we think the Hyperlamina Spark 35 will be fine for sleepers at 40F and above.
It's worth noting that warmth is also heavily influenced by conductive heat loss to the ground. Choosing an appropriate sleeping pad is important, especially in colder conditions or when sleeping on snow. Our Best Sleeping Pad Review will point you in the right direction for a warm, comfortable pad. Choosing the right backpacking tent or ultralight shelter for your trip will also influence the perceived warmth of a sleeping bag. OutdoorGearLab also has an excellent Backpacking Tent Review and Ultralight Backpacking Shelter Review, where you can finish out your research on the best sleeping/shelter kit for your next trip.
The sleeping bags in the review were tested in single wall tents, under tarps and mids, and under the open sky during open bivies above tree-line. See the Buying Advice on how standardized testing has helped (or hurt!) companies decisions on what temperature rating to give a sleeping bag.
Weight is a function of insulation type and amount, shell material, and features. In general, heavier bags use either synthetic insulation or lower fill-power down (500-700). Many of the highest performing bags we tested here use the best down (800-850+ fill-power) and very lightweight, expensive shell fabrics. A bag's cut and its overall dimensions also play a major factor in the weight of a bag as described above, and its features, or lack thereof.
At 1 pound 6 ounces the Sea to Summit Spark III is the lightest down bag we tested. It's no surprise the Spark III features high quality 850+ fill-power down, sports the tightest cut, lightest 10D shell fabric, and the shortest (1/3 length) zipper. What is amazing is the Western Mountaineering MegaLite is only 2 ounces heavier (1 lb 8 oz) but offers a full-length zipper, comparable warmth, and much more spacious (but still efficient) dimensions.
The Marmot Hydrogen was also among the lightest bags in our review (also 1 lb 8 oz), but wasn't quite as roomy as the MegaLite (it does cost $120 less). Among 20°F options, the Western Mountaineering UltraLite was pretty unbeatable; it was warmer than most 20° bags, yet also among the lightest (1 lb 13 oz). While both scored a 10 out of 10 for warmth, the Ultralite was not quite as warm as the reasonable priced REI Igneo, which was a 1 lb 13 ounce 25° option.
Among synthetic bags, our testers were very impressed with the Mountain Hardwear Hyperlamina Spark 35. While not super warm for its temperature rating, at 1 lb 13 ozs it was an exceptionally light synthetic option - and was lighter than several 30°F down bags.
Comfort is a pretty subjective category that depends primarily on fit, sleeping style, and internal fabric. Increasing the size of the bag's internal dimensions (to a point) generally provides most perceptions of what people would consider a more comfort bag, as the user has slightly more room to move around within a bag. This becomes even more important as users sleep on their side, tummy, and/or with their knee slightly out to the side - which is a common position for backpackers who like to sleep on their stomachs. Obviously the disadvantage of just making the bag bigger is that the company needs to add more material and insulation to maintain the same warmth; this often comes with a weight and packability penalty.
In addition to space for sprawling and thrashing, our ratings focus on a bag's features that will contribute to or detract from comfort. Insulation type influences comfort; all of our testers agreed that sleeping in a high-quality down bag is like floating on a super light cloud, while zipping into a synthetic bag is fine but .well, less heavenly.
The Sierra Designs Backcountry Bed 3-season and the Nemo Salsa 30 were the most comfortable bags in our review, with the Western Mountaineering MegaLite being a very close second. What makes the MegaLite special is it's significantly lighter and more packable than the two aforementioned bags, but nearly as comfortable. The Nemo Salsa 30 was our side and tummy sleepers favorite bag because we were able to sleep in those positions the most comfortably when compared to any bag in our review. We were also able to have our knees extended nearly straight out to the side while sleeping. What we also really liked about the Salsa 30, when compared to the Backcountry Bed, is that it was still a reasonable weight (2 lbs 1 oz) and a respectable packed volume that we would still consider bringing on a week-long backpacking trip.
The Sierra Backcountry Bed remains a pretty cool and very uniquely designed bag that offers the most "bed-like" feel of any bag we've ever tested. It features no zippers, toggles or Velcro flaps of any kind and instead offers a large "U"-shaped opening, that is covered by a down flap that acts (and feels) like a quilt. This not only helps regulate temperature extremely well, but also offers unmatched freedom of movement in the users upper extremities. While we thought this bag was awesome, it is the heaviest and least packable bag in our review, which is why it lost out on our Top pick award for the best Backpacking Bag for Comfort. While the Sierra Designs Backcountry Bed offers a mega comfort-oriented design, its lower dimensions were average and not as spacious as the MegaLite or Salsa 30. It also did not offer as nice feeling of an internal fabric.
It's worth noting that it is important to consider total comfort throughout the course of a trip, not just when you're inside your sleeping bag at night. A bag that's slightly more comfortable to sleep in may be far heavier and bulkier, and therefore less comfortable to carry. If you spend more time carrying the bag than you do inside of it, we suggest prioritizing weight and bulk (comfort while in your pack) over comfort while sleeping.
Features and Design
We assessed the quality of each of the bag's features and attempted to quantify how well they contributed to the overall performance of the bag. This variable encompasses shell fabric, zippers, draft tubes, neck baffles, and stash pockets. Traditional bags with snag-free zippers, easy-to-use hood adjustments, and hoods that don't come undone at night scored higher in this category, such as the Marmot Hydrogen and the Western Mountaineering Ultralite and MegaLite.
In most cases, more features or more complicated features can reduce performance. They add weight, complexity, cost, and the possibility of failing faster. The potential benefit a given feature has on warmth, comfort, or convenience is rarely offset by its drawbacks. Take stash pockets on sleeping bags, for example. It can be helpful to keep your watch with an alarm in the pocket, but it can be hard to hear the alarm through the down; if you roll in your sleep, waking up on your watch isn't exactly comfortable. In general, when it comes to features, smart design scored well and generally, less is more.
Three-season models are meant to be used in a wide range of conditions. They must function on warm summer nights at lower elevations, as well as when the temperatures drop below freezing near treeline in the fall. Versatility across environments, elevations, and seasons is an important consideration when assessing a bag's performance and value.
Some of the bags tested here, such as the Western Mountaineering Ultralight and MegaLite have continuous horizontal baffles that allow you to shift down from the top to the bottom of the bag, increasing comfort in warm conditions and warmth in cold conditions. We find these lightweight bags to be the most versatile in our test.
Other features that increase a bag's versatility is the ability to vent on warmer nights, meaning a longer zipper offers more versatility than a 1/3 length one. A little extra shoulder room to facilitate adding one (or more) layers can be nice on those colder adventures.
The Sierra Designs Backcountry Bed 600 3-Season has no zipper to roll onto and incorporates a quilt that enables you to sleep more like you would with a comforter at home. The quilt can be tucked into the bag when temperatures near the bag's comfort limit and is left outside the bag for warm nights and sleeping on your stomach.
Check out the chart below to see where each sleeping bag ranked in our Packed Size metric.
Packed size is a function of down fill-power, shell and insulation fabrics, and features. Higher quality down, lighter fabrics, and simple features create the most compressible bags. Obviously a more compressible bag is the better option, as it either gives us more room in our packs, or lets us take a smaller, lighter weight pack for a given objective. The most compressible bag in our review is the Sea to Summit Spark III which was slightly (10-15%) smaller than the Western Mountaineering MegaLite and Marmot Hydrogen.
Unfortunately, very few bags come with decent quality stuff sacks and many bags come with downright terrible stuff sacks. An exception is the Mountain Hardwear Hyperlamina Spark 35; in general, to maximize the compressability of your bag, we highly recommend purchasing one separately. See our Best Sleeping Bag Stuff Sack Article for our recommendations for specific applications.
Other Sleeping Bag Reviews
We also offer an Ultralight Sleeping Bag Review, which compares hoodless options, weighing only 19 ounces or less. If you're looking for a lightweight bag that will primarily be used for overnight trips where weight is a concern, we highly encourage you to consider one of the models found in the Ultralight Bag Review.
Lastly, we offer a general Camping Sleeping Bag Review that compares large and luxurious rectangular bags that are too heavy to carry backpacking. These offer much more comfort than any model tested here and cost as little as forty dollars!!
If you are a woman and are looking for a new sleeping bag, check out The Best Women's Sleeping Bag Review to learn more about the merits of buying a women's specific bag.
— Ian Nicholson
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