Looking for the best ultralight sleeping bag? Over 8 years we've tested 40+ UL bags we buy ourselves. Our updated review compares 14 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.
The Best Ultralight Sleeping Bags
|Price||$364.00 at Feathered Friends||$300 List||$410.00 at Backcountry|
Compare at 2 sellers
|$379 List||$266.03 at Amazon|
Compare at 3 sellers
|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||Warmer than the fully hooded mummies lighter than it, comfortable liner material, roomy footbox, ¾ length zipper|
|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||More suitable for 40F temps than 30, no neck baffle, zipper catches on fabric easily|
|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.||A great choice for those who want the lightest bag they can get but still want a fully un-zip-able mummy bag.|
|Rating Categories||Flicker 40 UL||Revelation 20||Summerlite||ZPacks Classic||Marmot Phase 30|
|Specs||Flicker 40 UL||Revelation 20||Summerlite||ZPacks Classic||Marmot Phase 30|
|Style||Center zip mummy bag or unzipper to be quilt||Quilt||Hooded Mummy||Hoodless mummy||Hooded Mummy|
|Manufacturer Stated Temperature Rating||40F||20F||32F||20F||30F (EN Comfort = 42F)|
|Measured weight, bag only (ounces)||19.1 oz||20.9 oz||19 oz||20.3 oz||18.3 oz|
|Claimed weight from manufacturer (ounces)||20 oz||20.19 oz||19 oz||19.8 oz||17.6 oz|
|Stuff Sack Weight (ounces)||0.8 oz||0.6 oz||1 oz||0.9 oz||0.9 oz.|
|Stuffed Size||7" x 10"||7" x 12"||6" x 12"||6" x 12"||12" x 7"|
|Fill Weight||8.4 oz||13 oz||10 oz||13.1 oz||8.5 oz|
|Fill Power||950+ Goose Down||850 Downtek||850+ goose down||900 fill||Certified 850 fill with Down Defender treatment|
|Construction||Continuous baffles||U shaped baffled quilt||Continuous baffle||Vertical upper baffles and horizontal lower baffles, box baffle construction||Smooth-Curved Baffles|
|Shell Material||Pertex Endurance UL||10D nylon fabric||100% nylon ripstop||.70 oz/sqyd (23.7 g/m2) Ventum Ripstop Nylon w/ DWR||10D Pertex (100% nylon ripstop)|
|Shoulder Girth (inches)||62"||55"||59"||61"||60"|
|Hip Girth (inches)||48"||55"||51"||61"||58"|
|Foot Girth (inches)||39"||55"||38"||35"||45"|
|Zipper Length||Full length center zip||1/3 length at bottom||Full length||3/4 length||Full length two-way|
|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)||Regular, long|
|Temp Options ( degrees Fahrenheit)||20, 30, 40F||10, 20, 30, 40F||32F||10, 20, 30, 40F||30F|
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 already mentioned 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
Sometimes the oldie is the goodie. 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 is 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 awarded an Editors' Choice 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 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 Buy on 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 Water Resistance
Marmot Phase 30
Looking to go ultralight, but worried about using a down-filled model in a wet climate? Then we recommend you check out the Marmot Phase 30, our Top Pick for Water Resistance. It uses a combination of Pertex Quantum shell fabric and Marmot's proprietary Down Defender DWR treatment for the 850 fill power down. Down has the best warmth-to-weight ratio of any insulation, which is why we have chosen only down-filled bags for this review. But where down has historically failed is in wet climates; if it gets wet, it loses 90% of its loft, as well as its heat-trapping properties, and it's hard to get it to dry out well in the field. For this reason, outdoor enthusiasts have long been discouraged from trusting down in wet climates, and with good reason.
Many companies now use "hydrophobic down," which is treated with a DWR (durable water repellent) coating to repel water. Marmot claims that their Down Defender treatment allows their down to stay dry longer, maintain more loft, and dry out quicker than untreated down. While we couldn't verify their exact percentages, our anecdotal testing indicated to us that this technology seems to work. Combined with the capillary wicking and natural water-resistant Pertex Quantum 10d fabric on both the inside and outside, the Phase 30 offers up a formidable barrier against soaking rains. It didn't seem particularly warm though, so if you're a cold sleeper or usually camping around 30F, we'd recommend the Marmot Phase 20 instead. If you commonly backpack in the Northern Cascades or have a long-ingrained fear of combining wet weather and down insulation, either of these could be the perfect bag for you.
Read Review: Marmot Phase 30
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, and we think it's worth calling it our Top Pick for Insane Packability.
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 and Ethan Newman. Andy has published guidebooks, climbed everything from mountains in Peru to boulders in the USA, 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. Combined, they spend over one hundred 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 assess each of these bags, we put them through a series of tests and uses to evaluate quantitative measures, like weight, fill power, features, and absolute warmth, and field testing to assess qualitative measures. Every bag was used in the field for multiple nights, often by numerous testers, trying to use it as close to the stated temperature rating from the manufacturer.
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 thorough design, there's only so far these things 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 lighter, 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. The bags and quilts in this review span from 12 ounces to a bit under two pounds, whereas our Backpacking Sleeping Bag Review has bags ranging from over one to three pounds. 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 with our Best Buy Awards to help those looking to save a bit of cash.
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.Related: The Best Backpacking Sleeping Pads
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. Three of our 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.
What separates this review from other sleeping bag reviews we've done is weight. Ultralight backpackers differ from regular backpackers by having a base weight (nonconsumable 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.
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. As the second most important metric, weight accounted for 25% of a product's final score.
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.
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.
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. 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-light is the Western Mountaineering Highlite, 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, 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, all 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 roomy, 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. Little details like 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 things also affected the comfort score of each product.
Ultimately, the Patagonia 850 Down Sleeping Bag 30 is the most comfortable mummy bag due to its generous sizing around the torso, the deep fitting hood, and a unique foot box design that is wider, taller, and more spacious than the tighter cut of the legs above it. The little things such as a zipper baffle, drawcords on the outside of the collar, and cord lock buckles recessed within the fabric also ensured that sleep isn't disturbed. Slightly lower scoring, but still among the top contenders, is the Feathered Friends Vireo UL, 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.
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. Our favorite choice for battling wet weather is the Marmot Phase 30, which includes a fantastic combination of Pertex Quantum shell and Marmot's Down Defender treatment. 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, our Editors' Choice-winning 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 Patagonia 850 Down also has a great set of features, including a central, two-way zipper that is ideal for accessing a tie-in point while alpine or big-wall climbing or for simple ventilation, and neck drawcords that live on the outside of the bag so the cords don't dangle in your face or wrap around your neck. We also like how the drawcord locks around the face are recessed inside the fabric for a more comfortable surface where your face rubs. Our Best Buy-winning Revelation 20 also has a great set up features, although not quite as good as the other two mentioned above.
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, bike-packing, alpine climbing, adventure racing, and bike touring all use ultralight systems to go further, faster into the wilderness. We poured through hundreds of sleeping bags to find the best and most popular sleeping bags and put them to the test from mountains to deserts to give you the best possible review we could.
— Andy Wellman and Ethan Newman