Looking for the best ultralight sleeping bag? Over 9 years we've tested 40+ UL bags we buy ourselves. Our review compares 13 top models currently available. Our team of backcountry enthusiasts and thru-hikers spent countless nights testing these bags across the world. From blustery mountain passes to hidden desert canyons, from the Himalayan Mountains to ranging across the Colorado Plateau, we carried these bags for miles. We also put them through controlled temperature testing. No matter if this is your first foray into the ultralight world or you're an old hat looking to update your gear, we're here to help you find the perfect bag for your ultralight adventures.Related: Best Ultralight Tent of 2021
Best Ultralight Sleeping Bags
|Price||$364.00 at Feathered Friends||$300 List||$410 List|
Check Price on Amazon
|$379 List||$329.00 at Feathered Friends|
|Pros||Highest scoring ultralight sleeping bag, best features, and most versatile||Very affordable, highly customizable, versatile, lots of features||Warmth-to-weight ratio, excellent fabric, best bag with a hood, versatile||Warm for an ultralight bag, simple and versatile design, box baffle construction, waterproof stuff sack||Super simple and light, highest quality down, spacious and comfortable|
|Cons||Not as warm as others (in the version we tested), neck draw cords loosen over time||Long wait for product to be custom made and shipped, foot box draw cord still leaves a little hole, lots of buttons and straps||Tight fit, shallow hood, expensive||A little constricting, small foot box, not the best neck draw cord design||No zipper, hard to tell the difference between variable fill zones, must be paired with warm jacket, feet can get hot in warmer weather, not as versatile as other ultralight bags|
|Bottom Line||The best performing set of features that allow for the most versatile usage||The warmest quilt in our review also comes at a reasonable price||A very warm and lightweight full mummy with a full zip||With an enclosed foot box and ¾ length zipper, this warm hoodless mummy can also be used quilt style||The only mummy bag that uses more down fill in the foot box and less around the torso, to take advantage of the clothing you have with you|
|Rating Categories||Flicker 40 UL||Revelation 20||Summerlite||ZPacks Classic||Feathered Friends Vireo UL|
|Specs||Flicker 40 UL||Revelation 20||Summerlite||ZPacks Classic||Feathered Friends...|
|Style||Center zip mummy bag or unzipper to be quilt||Quilt||Hooded mummy||Hoodless mummy||Hoodless, zipperless mummy|
|Manufacturer Stated Temperature Rating||40F||20F||32F||20F||25F lower half, 45F upper half|
|Measured weight, bag only (ounces)||19.1 oz||20.9 oz||19 oz||20.3 oz||16.4 oz|
|Claimed weight from manufacturer (ounces)||20 oz||20.19 oz||19 oz||19.8 oz||16.7 oz|
|Stuff Sack Weight (ounces)||0.8 oz||0.6 oz||1 oz||0.9 oz||0.8 oz|
|Stuffed Size||7" x 10"||7" x 12"||6" x 12"||6" x 12"||7" x 10"|
|Fill Weight||8.4 oz||13 oz||10 oz||13.1 oz||9.4 oz|
|Fill Power||950+ goose down||850 Downtek||850+ goose down||900 fill||950+ goose down|
|Construction||Continuous baffles||U shaped baffled quilt||Continuous baffle||Vertical upper baffles and horizontal lower baffles, box baffle construction||No hood, no zipper and a variable fill|
|Shell Material||Pertex Endurance UL||10D nylon fabric||100% nylon ripstop||.70 oz/sqyd (23.7 g/m2) Ventum Ripstop Nylon w/ DWR||Pertex Endurance UL|
|Shoulder Girth (inches)||62"||55"||59"||61"||64"|
|Hip Girth (inches)||48"||55"||51"||61"||48"|
|Foot Girth (inches)||39"||55"||38"||35"||38"|
|Zipper Length||Full length center zip||1/3 length at bottom||Full length||3/4 length||No zipper|
|Sizes||Regular, long, and wide||Short/regular, regular/regular, regular/wide/ long/wide||5'6", 6', and 6'6"||Slim, standard, and broad (girth) short, medium, long, x-long and xx-long (length)||62", 68", and 74"|
|Temp Options (degrees Fahrenheit)||20, 30, 40F||10, 20, 30, 40F||32F||10, 20, 30, 40F||25, 45F|
Best Overall Ultralight Sleeping Bag
Feathered Friends Flicker 40 UL
Due in large part to its incredible versatility, the Feathered Friends Flicker 40 UL is the highest rated bag in our review, yet again. Whether you are trying to ventilate on a hot night or bundle up to stay warm when the temperature drops, this bag has you covered. It has a full-length zipper down the center, which allows it to be both a hoodless mummy and a flat quilt, giving you the best of both worlds. The Flicker 40 pairs super high loft, 950+ fill quality down with a shell made of naturally water-resistant and breathable Pertex Endurance UL. Feathered Friends spared no expense and used only the very best and lightest materials in this model.
This is not the warmest bag — we opted to test the 40F version to check out the lightest Flicker available, and it kept us warm in that temperature range, but any colder and we weren't as toasty. Check out the 30F and 20F options if you want extra warmth for a bit more weight. The lack of a hood also makes it less warm on cooler evenings. We like the dual drawcords at both the head and feet, which lets you wear it around camp on chilly mornings, and the full-length zipper is far higher quality and more functional than the weight saving buckle or strap systems used on some competing quilts. The Flicker is the clear winner of our comparative review, and we happily recommend you begin your search for an ultralight sleeping bag right here.
Read review: Feathered Friends Flicker 40 UL
The Best Ultralight Hooded Mummy Bag
Western Mountaineering Summerlite
When something is designed well, why change things up for the sake of change? The Western Mountaineering Summerlite has been around a while and is a standard for a lot of good reasons. It's really warm and while it isn't EN rated, we think Western Mountaineering's approach to temperature ratings tends to be a lot more accurate than others. The Summerlite sandwiches high-quality 850 fill power down between lightweight 12D fabric coated in a robust DWR to make one toasty package for a good night's sleep. Despite the full-length zipper and hood, the Summerlite comes in at a competitive fighting weight of 19 ounces. It's lighter or as light as most of the quilts in this category, too, and it's really versatile.
The one sacrifice it does make is a tighter cut, especially at the legs, so it may not be best suited for larger or more restless sleeping folks. Because it's a regular mummy, it's less dependent on fitting with a specific pad, so it can be used whether you're stretching out in a hut along the Appalachian Trail or curled up on a too-short ledge on the side of Fitzroy. The Summerlite is our favorite mummy bag among all we tested.
Read review: Western Mountaineering Summerlite
We know, we know: this can be a polarizing topic. We believe there are excellent arguments on both sides of the aisle on this one and therefore, we chose a favorite bag for each type. Some of our testers prefer quilts, some prefer mummies, and that's just fine. We set out on this review to speak to both schools of thought. Our only firm judgment is that your needs supersede anyone else's opinion on the matter.
Best Bang for the Buck
Enlightened Equipment Revelation 20
For many of us, the weight to warmth ratio isn't the only consideration of our gear; it's also price. We think that the best balance of all three is the Enlightened Equipment Revelation 20. It didn't score quite as high as the Feathered Friends Flicker, but for a reasonable price plus free shipping in the USA, it's hard to find a bag as versatile and warm as this one. The quilt can be opened up into a blanket for summer nights, or sealed down around a sleeping pad for maximum warmth. The Revelation is customizable in about every way, from fill power, different weight fabrics, width and length, and even colors. We tested the "stock" model for this review — beware that customizing this quilt can take 2-4 weeks for delivery, but you with a plethora of customizing options, you can really dial this one in to meet your specific desires.
If you're close to the limits of the dimensions of the quilt, we recommend sizing up, as our larger testers found the quilt a bit constricting when entirely closed up. The attachment system, while very adjustable, is a bit dangly, which we sometimes found annoying. However, the current model is the warmest quilt we tested, and quite comfortable in a wide range of temperatures, and it scored well in our tests. For a great quilt with a justified price, the Revelation is a worthy contender.
Read review: Enlightened Equipment Revelation 20
Best for a Tight Budget
Hammock Gear Burrow Econ 20
For some ultralight backpackers, spending more is worth it to drop a few extra ounces, but as the Econ line from Hammock Gear proves, you don't need to break the bank for a quality lightweight quilt. We tested the Econ Burrow 20, and we were surprised at how well it performed despite being over a hundred dollars cheaper than many of the other options. It's got as many features as some of the more expensive options and isn't that much heavier.
We tested the Econ Burrow in the backcountry of Zion National Park and Joshua Tree, and it kept us warm on nights around freezing and packed down surprisingly well too. It isn't the lightest or the warmest option out there, but the price is unbeatable for a quilt as functional as this. The size, temperature, fill, and footbox style can all be customized as well, which does affect the price, but it still stays under the cost of nearly every other option. For bargain shoppers, this is your bag.
Read review: Hammock Gear Econ Burrow 20
Best for Insane Packability
Sea to Summit Spark SpI 40
There are those who go light, and there are those who go truly ultralight. The Sea to Summit Spark 40 is for those in the latter category. At a mere 12.4 ounces, this thing is so light and small, you might lose it in your pack. The Spark comes with a compression stuff sack than shrinks this down to about one liter of space. We took this backpacking on a late summer overnight backpacking trip in southern Utah and easily packed everything into a 20-liter daypack. If you were really careful about it, you could probably get away with an ultrarunning vest.
The folks over at Sea to Summit made this tiny package possible by stripping nearly everything off this hooded mummy bag. There's no draft collar or tube, only a half zipper, and the baffles are sewn through the shell fabric. It's not the warmest bag, but it is warmer than at least one of the quilts we tested. For seriously light summer missions, it's one cool piece of gear.
Read Review Sea to Summit Spark SpI 40
Why You Should Trust Us
We assembled an all-star crew to put these ultralight sleeping bags to the test, including Andy Wellman, Ethan Newman, and Justin Simoni. Andy has published guidebooks, has hiked long distances in the Rockies, the Andes, and the Himalayas, and is no stranger to a night under the stars. Ethan has worked professionally outdoors for over a decade, including working as a rock climbing guide, wildland firefighter, wilderness ranger, and environmental educator. Justin has explored the more exhilarating peaks and ridgelines of Colorado, finishing bold fastpack routes on his unsupported multi-day adventures, and has assisted with guided ultralight backpacking trips in Kings Canyon NP, Rocky Mountain NP, and Gates of the Arctic NP. Combined, they spend over 150 nights a year in a sleeping bag, from shiver bivvies on the sides of mountains to comfy nights around a campfire with friends, and we know how to get a good night's sleep outside.
To us, there's really only one way to test how a product truly performs - by using it. With this in mind, we tested these bags by sleeping in them - outside - a lot. We used them on windy desert nights and blizzards at 15,000 feet, and everything in between. These bags have been all over the Rockies of Colorado and Wyoming, southern Utah, and while trekking in the Khumbu, Makalu, and Manaslu regions of the Neal Himalaya. Many people slept in each bag, and we've spent excellent and comfy nights in the wilderness, and shivered through enough sleepless nights to truly understand the meaning of "temperature ratings." One of our testers caught two colds that he blames on freezing all night in search of the truth about these sleeping bags. We went the extra mile to make sure we know what we're talking about, and we hope you find this review useful.
Analysis and Test Results
To compare and score every quilt and bag as objectively as possible, we narrowed down five metrics in which to evaluate each bag: Warmth, Weight, Comfort, Versatility, and Features. Because some of these categories are more significant than others, we weighted each one according to the relative importance for an ideal sleeping bag, scoring each metric from 1 to 10. Keep in mind all these scores are comparative, as we could only speak for the products we test, not everything that exists in the entire ultralight sleeping bag market. This is why a 30-degree Fahrenheit sleeping bag might score well in warmth; we are comparing it to other, similar sleeping bags, not a 0-degree winter bag.
While these bags use high-quality materials and well-executed design, there's only so far these things can go. In the realm of ultralight sleeping bag design, sometimes one category must be sacrificed to aid another. For example, a tighter cut may be lighter and warmer, but less comfy. Keep this in mind as you read through this review to find the best balance for your needs.
What does it mean to have an "Ultralight" sleeping bag? Ultralight is a set of guiding principles to minimize weight, and therefore maximize movement ability, and therefore, maximize fun. However, that means every ounce counts, and between warmth, weight, and comfort, you often have to pick two out of three. Some bags reduce weight by a narrow cut, or utilizing lighter and less durable fabrics, or being rather generous about the concept of warmth.
A recent ultralight trend utilizes quilts instead of full sleeping bags. The idea is that any down or fabric underneath you is compressed and ineffective, so why not eliminate it? Other bags eliminate hoods, shorten zippers, or strategically place the down fill to maximize warmth while keeping the weight down. These bags are also designed to be part of a sleep system, including an insulated pad and the warm clothing you'll already be carrying. Still, other products blur the line between sleep bags and quilts and cherry-pick great ideas from both types of offerings.The bags and quilts in this review span from 12 ounces to a bit under two pounds, while we consider backpacking models to weigh up to about 3 lbs. It may not seem like much, but as ultralight hikers say, "ounces make pounds, and pounds make pain." If you're not sure which category is right for you, be sure to check out them both.
One consideration we often mention (but don't score for) is value. Is the bag you're buying worth the price? With all the systems necessary for backpacking and other overnight wilderness travel, purchasing wisely can save you quite a bit of cash without compromising performance in the backcountry. Although we don't include it in the ratings, value is an important consideration. While new gear is exciting, most of us still desire to pay less for the equipment we want or need. This means knowing whether shelling out extra dollars is worth it. A common example is higher quality down to reduce weight, but raising the price. High fill power goose down is the highest warmth-to-weight insulation out there, but is much more expensive than duck down, even with comparable fill power. Higher prices can mean a higher quality product, but not always. Even if it does perform better, is it worth the extra cost? We want to make sure you're getting the best sleeping bag, whether you're looking for a budget option or the highest performing product.
One way to evaluate value is to use it as an index to compare to the overall score we've given to each product. For example, two bags could score similarly with our evaluation, but one could cost significantly more. All things being equal, the less expensive option would provide greater value. Without scoring for value, we've tried to highlight some less expensive options to help those looking to save a bit of cash. We feel that the Enlightened Equipment Revelation 20 provides top-notch overall performance with the fairest price tag. It's not inexpensive, but it does cost significantly less than high-end products that it compares well to. The Hammock Gear Econ Burrow is a step down in performance, but we still feel that many people will be satisfied by the level of performance, especially considering the price savings. This model proves that you can still get a pretty good UL model on a tighter budget.
One product that may find itself as a great introduction to quilts for the masses is the REI Trail Magma 30. The quilt is one of the few you'll find mass-produced and should be widely available. Although easily available and faring well-enough on our warmth tests, we still had a few unanswered questions dealing with its long-term durability, and lack of versatility. Although a great introduction, it may not be a product that will grow with the owner as she becomes more advanced in their backpacking objectives.
No matter how fast and light you go, eventually, you'll have to stop and recover. Being able to get a good night's sleep is essential to going hard again the next day. A warm sleeping bag is paramount for both comfort and safety. Many ultralight hikers consider it the "ultimate layer." If your sleeping system, including your pad and warm clothes, doesn't keep you warm enough to recover from a long day of climbing, hiking, or biking, it doesn't matter how lightweight it is.
Fortunately, the bags we tested mostly have good to excellent warmth-to-weight ratios, using quality materials and innovative construction. We strongly believe that you should choose your bag on the conditions and temperatures you expect to encounter. Because warmth is the main purpose of an ultralight sleeping bag, it counts for 30% to each product's overall score.
Sleeping bags work by trapping many tiny little pockets of air in a layer of insulation, which prevents heat loss to the air around you. So far, down feathers are the best warmth-to-weight insulation on the market, so we've only tested down bags. These bags only use high loft down, most of them with 800 or higher fill power. To keep the down in place, manufacturers also use baffles, thin pieces of fabric to create separate chambers to make sure the insulation is where it needs to be, whether spread evenly or placed strategically. Box baffles, sewn-through construction, and other designs all work differently to achieve different design goals.
Most sleeping bags and quilts come with a temperature rating recommended by their manufacturer (i.e., 20F). However, these numbers can be confusing and even misleading. On one particularly rough night of "product testing," we slept in two bags, each rated to 15F at around 15,000ft. in Nepal. It happened to snow that night, and the temperature dropped to 10-15F. Wearing all of the clothes we each had, we still both spent the night shivering mercilessly, didn't sleep for a minute, and welcomed the 3 am pre-dawn wake-up call simply to get moving again. These models did not perform well at their stated rating, so what gives?
There is only one standard for sleeping bag temperature ratings, the EN 13537 standard. For a sleeping bag to qualify for the test, it must have a hood, which rules out several bags in our review. The EN 13537 gives a sleeping bag four ratings, but the two to look at are "comfort" and "lower limit." Most manufacturers publish the lower limit as their advertised rating, but be aware that the lower limit is defined as "the temperature at which a standard male can sleep in a curled position without waking," which assumes a "standard male" is 25 years old and sleeping in the fetal position. The "comfort" rating is the temperature a "standard female," also 25 years old, can sleep in a comfortable and relaxed position.In the case of the two of the bags we shivered in, the lower limit was listed as the rating. It is true that we didn't freeze to death that night, but hidden on their websites was the (real) helpful information that these bag's comfort ratings were in the upper 20's. For sleeping bags that didn't qualify for or didn't receive the EN standard test, it is not clear where the temperature rating comes from. And even those that did get a standard rating, the published numbers are most often misleading. So, take those temperature ratings with a grain of salt.
While the fill is one of the key factors in the warmth of a bag, we found that the design is just as big a factor, and can be the difference between sleeping comfortably and shivering miserably. Features like closed foot boxes, draft collars, hoods, zipper baffles, and pad attachment systems (for quilts) can separate products that list the same fill weight. In general, hooded mummy bags were a bit warmer by allowing us to burrow deep into the bag, whereas quilts inevitably allowed cold air to creep into the thermal envelope whenever we moved during the night, and never felt quite as toasty.
All ultralight sleeping bags, but especially quilts, are designed to be part of a sleep system: the bag, the pad, and your clothing. Tailor your system to work in unison to keep yourself as comfortable and warm as possible. Most of the quilts we tested aren't designed to enclose the user fully but instead attach to an insulated sleeping pad to form a warm envelope. The theory behind quilts is that the sleeper compresses any down below them, negating any insulating effect it would otherwise have, so why not get rid of unnecessary material and save the weight? This can work well but requires careful selection of a sleeping pad to pair with a quilt, and the pad absolutely must be insulated.
The higher the R-value of a sleeping pad, the more insulating the pad is from the ground. During our testing on cold nights, we found that some quilts left something to be desired, and would have liked some extra insulation below us to fill in the gaps. Make sure your insulated pad fits your quilt, and that any extra clothing won't compress the insulation, reducing effectiveness. Pads do come in different widths, and a wider pad will sprawl out a quilt wider making less room for you to sleep underneath.Related: Best Backpacking Sleeping Pad of 2021
We made a point of testing each of these bags while sleeping in temperatures very close to their stated ratings, catching two colds and spending more than a few nights shivering in the process. These experiences have taught us which bags are warm and which are not, and we rated these bags for absolute warmth, meaning the warmest got the highest score, and the coldest got the lowest score.
Several bags tied for warmth (in proportion to their rating): the EE Revelation 20, the Zpacks 20 Degree, and the Western Mountaineering Summerlite. The Western Mountaineering bag is a hooded mummy bag that allows a nearly complete thermal envelope around the sleeper, keeping in as much warmth as possible. The Zpacks and Revelation bags was also very warm, but lacking a hood requires a warm hat or hooded jacket to insulate your head.
While we love quilts for their versatility and spaciousness in warmer weather, our testing revealed that in cold weather, they don't seal off as well and can't keep us as warm as mummy-style bags.
The REI Magma Trail 30 quilt fared pretty well in our testing when it came to warmth for a quilt but was a bit finicky to set up correctly. Much of its warmth comes from removing features that add to the versatility of a quilt. For example, the toasty footbox is clutch in facilitating keeping the rest of us warm, but it lacks the option for any sort of foot ventilation, or the ability to transform the entire quilt into a blanket. This may make things a little too toasty on warmer days.
What separates this review from other sleeping bag reviews we've done is the weight. Ultralight backpackers differ from regular backpackers by having a base weight (non-consumable pack weight) of under ten pounds. The idea is that ultralighters are willing to make some compromises in comfort or convenience to have the benefits of a light pack. A ten-pound base weight can be achieved with any of the products in this review, but if you're going super ultralight, pay extra attention to the weight score. As the second most important metric, weight accounted for 25% of a product's final score.
It is worth noting that in almost all cases, we chose the model or option that was the lightest weight, usually going with a higher temperature rating to do so. For those who want a bit more warmth and are willing to carry a few extra ounces to have it, there are usually slightly heavier, and warmer options available compared to what we tested. Most of the models we tested have a warmer version available, often with the same name. Many of the products we tested have an incredible spread of parameters you can customize, including overfilling the bag and adding draft tubes. These options can significantly affect the relative comfort temperature of your custom bag but may take longer to receive and add to the price of the product.
When it comes to ultralight sleeping bags, most managed to shave weight with a combination of really high-quality down, and pared-down features and design. Down provides the highest warmth-to-weight ratio of any insulation, which is why it is the insulation of choice in the very lightest products. Down is rated by its fill power, and the higher the number, the more it will loft up, and thus the higher quality. In most cases, the bags tested in this review use down with a fill power of 800 or more. The fill power and quantity of down used in each competitor can be found in the specs of each product.
In the case of most quilts, weight is saved by eschewing fabric or insulation on the underside of the bag. Lightweight straps or string systems help latch the sides of the quilt around the user or a sleeping pad, thereby saving the weight of a zipper as well. Quilts also forego the hood, thus avoiding the weight of more fabric and insulation. Some models also feature snaps to wrap the quilt around one's neck while sleeping — a nice feature but it also increases weight.
Mummy bags, on the other hand, employ other tricks to save weight. Ultralight fabrics, both on the shell and baffles, reduce weight but usually make the bags more delicate. Smaller zippers have the same effect, and they often only go half the length, reducing venting possibilities. Most ultralight mummy bags are also cut more narrowly, as less fabric all around makes a lighter bag.
When calculating the overall weight of your sleep system, factor in how versatile your sleeping bag and quilt will be taking on different tasks. Quilts and full zip sleeping bags can keep you warm on cold mornings as you get ready for the day's hike, which may mean you may be able to optimize on your insulation layer. If you think you'll require additional warmth for your head at night, as most quilt users will probably want, source a nighttime insulated cap that can also play double-duty while out on the trail.
We weighed these bags individually on an independent scale to determine the weight and then assigned the scores comparatively. In the case of quilts where extra straps or buckles were required to close up the quilt or affix it to a sleeping pad, we also included that weight, but we weighed the stuff sacks separately (as not everyone uses them on the trail).
Most impressive in this metric is the Sea to Summit Spark 40 mummy bag. It comes in at an insane 12 ounces and packs down to the size of a water bottle, eschewing baffles for a sewn-through design, and keeping the cut narrow and the fabric light. Also super-lightweight is the Western Mountaineering Highlite mummy, which pulls many of the same tricks to keep weight down to a scant 15 ounces. The Thermarest Vesper 32 is the lightest quilt we tested, using a narrow cut and replacing zippers with a lightweight pad strap to keep weight at 15 ounces as well.
The other half of the equation for a good night's sleep is comfort. Things like drafts, drawcords dangling in your face, buckles wedged underneath you, or a claustrophobic shape all detract from sleeping soundly. If you sleep well, you'll perform well the next day. There's nothing worse than to loathe actually getting into a subpar sleeping bag or quilt, which is why we think comfort is important enough to weight it at 20% of the score.
When assessing for comfort, the first thing we looked at is how well the bag fits. Our head testers are 5'11" and 5'8" and fairly trim, so we ordered all of the test models to suit a person 6'0" tall and standard width. By ordering them all the same size, we were able to compare the fit of each bag to the same standard. Luckily for you, most of the bags in this review come in different height and width options, making it easy to customize a bag for your particular shape.
Two aspects of a sleeping bag or quilt's fit were immediately noticeable: the length and the width. Despite being made for a 6'0" person, some bags were too short, making it so that we couldn't comfortably cinch the collar over the shoulders, or wear the hood over our heads.
Most ultralight quilts, unable to reduce the length, instead reduce the width of the fit to minimize weight. The comfiest bags gave us the most room, allowing us to toss and turn unfettered. Mummy bags are historically claustrophobically cut. But some, like the Feathered Friends Vireo UL, were generously fit. Quilts, on the other hand, offer plenty of room, but sometimes had the same issue when we utilized their pad attachment systems. Some quilts also were too narrow to wrap ourselves in on chillier nights, no matter how much we repositioned.
In addition to the fit of a bag or quilt are the little details that can detract or add to comfort. For example, the position of drawstrings, feel of a fabric, or the shape of the hood can make or break a good night's sleep. All these small elements also affected the comfort score of each product.
Ultimately, the Feathered Friends Vireo UL scored as the most comfortable sleeping bag or quilt whose vast and spacious cut in the torso is designed to accommodate the extra fill of an insulated jacket, but also left us feeling free to move about as desired. Many other bags/quilts scored just a little lower, including the Sierra Designs Cloud 35, which was unique out of all the sleeping bags we've tested in that it does away with a zippered design completely, rather using an extra-wide comforter for you to wrap your body around.
None of the top models of sleeping bags/quilts we are sharing reviews for are scoring outstanding when it comes to comfort. This doesn't in any way mean they're uncomfortable but does highlight that compromises in comfort are made to the bag in order to keep the weight down. If the compromises we've documented across all these products in the name of wearing the coveted "Ultralight" label is too much, consider more traditional backpacking sleeping bags.Related: Best Backpacking Sleeping Bag of 2021
If you want a three-season sleeping bag, or are planning an epic six-month thru-hike that will span the seasons of a cool spring into hot summer and back into a cool fall, then versatility is a critical metric. Versatility is the ability of the bag to be used comfortably in the most possible (different) situations. Questions we asked ourselves when rating each bag for versatility were: is it possible to wrap oneself up like a cocoon to stay warm on the coldest nights? Likewise, is it feasible to open the bag up and ventilate to stay cool on the warmest of nights? Sleeping bags that could do both with ease were the highest scorers when it came to versatility, and sleeping bags that pigeonholed themselves into only being practical in one season or temperature range scored the lowest.
In general, quilts are more versatile than ultralight mummy bags, whose half-length zipper designed with weight savings in mind often made it even harder to ventilate on warm nights. Quilts and bags that included full-length zippers, or quilts that were long enough and broad enough to wrap oneself up in fully, fared the best because they most easily allowed for staying warm on cold nights. Besides just being able to be used in both hot and cold seasons, we also looked at whether a bag would be serviceable in wet climates. Ultralight bags that used hydrophobic down, which is down that has been chemically treated to resist absorbing water and thereby losing its loft and warmth-trapping properties, received a bonus.
We also looked at whether a bag used a DWR (durable water repellent) treatment on its outer shell to protect it from absorbing liquids such as condensation, or used a naturally water-resistant fabric such as Pertex Quantum to accomplish the same thing. Lastly, we looked at how packable the sleeping bag is. The smaller it packs down, the easier it is to carry along with you, and for a few outdoor sports like bike touring or bike packing, this is a critical component of whether a piece of gear is useful or not. As an important metric, but not the most crucial metric, we weighted versatility as 15% of a product's final score.
The most versatile product without a doubt is the Feathered Friends Flicker 40 UL. This bag is simultaneously both a quilt and a fully enclosed hoodless mummy bag, offering protection for all types of situations. On the warmest nights, it can be used as a spread-out blanket, which is also ideal for two people, or as a quilt with an enclosed foot box by tightening the drawstring on the end and zipping it up partway. The full-length zipper means that on cold nights, it is possible to seal it up entirely and trap the warm air in with the help of a neck baffle with dual drawcords. No other bag so easily met the demands of all seasons. While we tested the 40F version of this bag because it was the lightest weight, it also comes in 30F and 20F versions for those who live and play in colder climates or seasons.
A unique approach to versatility is the Sea to Summit Spark 40. It doesn't span a great range of temperatures, but it scored higher than it otherwise would because it's so small and light that the Spark is easy to throw in nearly any pack. While we would only really use the Spark in warmer temperatures, we could nearly always take it with us, and not notice the extra weight. Because it's so packable and light, it received a higher versatility rating than a similarly rated bag otherwise might.
Near the top in the versatility department is the Zpacks Classic. A hoodless mummy bag that is rated to 20F features box baffle construction, and a DWR coated Pertex Nylon shell, the Zpacks Classic is ideal for cold nights. It also has a ¾ length zipper that allows one to open it up like a quilt for warmer nights. If you want an ultralight bag that you can utilize in all three seasons, be sure to pay attention to our versatility ratings.
The features metric provides the last piece of the puzzle for understanding how well an individual ultralight sleeping bag works or doesn't work. A sleeping bag is simply a down-filled sack or blanket designed to keep you warm at night, and the features are all those little components that make it work. Drawstrings, draft collars, zippers, hoods are all designed to enhance a sleeping bag into part of an efficient sleep system and conserve all the necessary BTU's you produce to sleep soundly.
The most common features found on these bags are zippers, draft collars, cinch cords around the neck, face, hood, or feet, and in the case of quilts, pad attachment systems. When assessing for features, we looked first at whether a bag's specific features functioned well or were finicky and annoying. Then we compared them to similar features on the other bags and rated them in comparison to all the others.
Zippers that wouldn't stay zipped or were continually getting stuck in fabric, pad straps that wouldn't stay attached or wouldn't lock in place, and drawcords that didn't have buckles or wouldn't stay tight, are examples of poorly performing features that caused us to knock the score down a bit. As something worth being aware of, but certainly not the most important overall metric, we assigned features 10% of a product's final score.
Once again, the Flicker 40 received the highest score for features. Not only did it have a ton of features — full-length zipper with a reinforced draft tube, drawcord enclosure at the feet, dual drawcord and neck baffle at the head, optional attachment points for DIY pad straps — but they all worked well. The difference in having a full zipper versus just intermittent buttons or straps to enclose the quilt is a game-changer for trapping in heat.
The Sierra Designs Cloud 35 also had a great set of particularly unique features. In fact, this sleeping bag seemed to really want to shine in a category all of its own between a sleeping bag and quilt. Zippers getting stuck within the shell fabric of the bag itself will never be a problem, as there are no zippers to get stuck! Along with a full zipperless design, the Cloud 35 has an interesting footbox vent, and an oversized quilt useful for either keeping loose on warm nights or tight on colder ones. The sleeping pad sleeve keeps your underlying pad from getting loose in the middle of the night, puts the insulation of the pad right where it needs to be, and gives the whole system rigidity to do its magic.
The Revelation 20 also has a great set of features, including a cleverly designed and versatile footbox that both vents and transforms the entire quilt into a blanket. Its warmth to weight ratio, especially when compared to its price for a US-made quilt, is also quite remarkable, and worth your time to consider.
The world of sleeping bags is flush with options, everything from old-school, square-cut monstrosities to airy space-age quilts and everything in between. For this review, we specifically singled out ultralight sleeping bag and quilt options, as more people realize than backpacking is more fun with less weight. Ultralight sleeping bags are best suited for warmer temperatures, but with proper planning and well-designed systems, they can be pushed into shoulder seasons. These are for going fast and light, where any extra ounces will slow you down and keep you from your goals. Activities like thru-hiking, fastpacking, bikepacking, alpine climbing, adventure racing, and bike touring all use ultralight systems to go further, faster into the wilderness. We poured through scores of ultralight sleeping bags and quilts to find the best and most models and put them to the test from mountains to deserts to give you the best recommendations possible.
— Andy Wellman, Ethan Newman, and Justin Simoni