The world's most in-depth and scientific reviews of outdoor gear

The Best Ultralight Sleeping Bags of 2019

Waking up to a chilly morning after sleeping out in the San Juan Mountains. The Vireo  in blue  and the HighLite in purple.
Monday May 13, 2019
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Ready to drop pack weight? We researched over 50 of the best ultralight sleeping bags and purchased 14 top bags and quilts for our side-by-side tests. Our expert testers spent hundreds of nights total in these bags in remote corners of the globe, from the Rockies to the Himalayas. We used them in various conditions and elevations, carrying them on our backs during the day. We evaluated them on their nighttime comfort, warmth, and more to determine our favorites. Your sleeping bag is an excellent place to start cutting pack weight, and whether you are a gearing up for a multi-month thru-hike or just getting into backpacking, we have some great recommendations for you and your 2019 adventures.


Top 14 Product Ratings

Displaying 1 - 5 of 14
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Awards Editors' Choice Award Best Buy Award Editors' Choice Award  Top Pick Award 
Price $339.00 at Feathered Friends$300 List$410.00 at Backcountry
Compare at 3 sellers
$379 List$398.95 at Backcountry
Compare at 3 sellers
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Pros Highest scoring ultralight sleeping bag, best features, and most versatileVery affordable, highly customizable, versatile, lots of featuresWarmth-to-weight ratio, excellent fabric, Made in the USAWarm for an ultralight bag, simple and versatile design, box baffle construction, waterproof stuff sackWarmer than the fully hooded mummies lighter than it, comfortable liner material, roomy footbox, ¾ length zipper
Cons 40 degree not as warm as others, neck draw cords loosen over timeLong wait for product to be custom made and shipped, foot box draw cord still leaves a little hole, lots of buttons and strapsTight fit, shallow hood, expensiveA little constricting, small foot box, not the best neck draw cord designMore suitable for 40F temps than 30, no neck baffle, zipper catches on fabric easily
Bottom Line The highest scorer because of its versatile design that allows it to be a fully opened blanket or a fully zipped hoodless mummy.Offers the versatility of sleeping under it as a blanket or fully wrapped up, with a huge range of customizable options.A stellar choice for those looking for a warm, lightweight, fully hooded mummy.A top-scoring bag that's warm and versatile enough for full three-season use, while weighing impressively little.A high-quality hooded mummy bag that is significantly lighter than a standard backpacking bag.
Rating Categories Flicker 40 UL Revelation 20 Summerlite ZPacks Classic Marmot Phase 30
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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


Editors' Choice Award

$339.00
(7% off)
at Feathered Friends
See It

72
OVERALL
SCORE
  • Warmth - 30% 6
  • Weight - 25% 6
  • Comfort - 20% 7
  • Versatility - 15% 10
  • Features - 10% 10
Weight: 19.1 oz | Fill: 950+ Goose Down
Can be used as both a quilt and mummy bag
Full-length zipper with baffle gives you complete enclosure
Uses the highest fill power down available
No hood
Not as feather-light as the lightest bags available

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


Editors' Choice Award

$410.00
at Backcountry
See It

70
OVERALL
SCORE
  • Warmth - 30% 8
  • Weight - 25% 6
  • Comfort - 20% 6
  • Versatility - 15% 8
  • Features - 10% 7
Weight: 19 oz | Fill: 850 Fill Down
A fully enclosed mummy bag with hood
Really warm and efficient
Lightweight for a full-zip hooded mummy
Tight cut
Shallow hood

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 at 19 ounces. It's lighter or as light as most of the quilts in this category too, and is fairly 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

Quilts vs. Mummy Bags
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


Best Buy Award

$300 List
List Price
See It

71
OVERALL
SCORE
  • Warmth - 30% 8
  • Weight - 25% 6
  • Comfort - 20% 6
  • Versatility - 15% 8
  • Features - 10% 8
Weight: 20.9 oz | Fill: 850 fill
Great price
Warm for a quilt
Uses high-quality DownTek treated 850 fill power down
Constrictive when fully buckled up
Long, dangly drawcords

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 very 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.

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


Best Buy Award

$160 List
List Price
See It

59
OVERALL
SCORE
  • Warmth - 30% 5
  • Weight - 25% 4
  • Comfort - 20% 7
  • Versatility - 15% 8
  • Features - 10% 8
Weight: 25 ounces | Fill: 800 fill DWR Duck Down
Bargain for what you get
Versatility
Customizable
Not that warm
Doesn't cinch as well as some

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

Top Pick for Water Resistance


Marmot Phase 30


Top Pick Award

$398.95
at Backcountry
See It

69
OVERALL
SCORE
  • Warmth - 30% 6
  • Weight - 25% 7
  • Comfort - 20% 7
  • Versatility - 15% 8
  • Features - 10% 7
Weight: 18.3 oz | Fill: Certified 850 fill with Down Defender treatment
Supremely water resistant
Lightweight for a fully hooded mummy bag
Full-length zipper
Not nearly as warm as its rating suggests
Zipper snags on draft tube

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 resistant) coating to repel water. Marmot claims that their Down Defender treatment allows their down to stay drier longer, maintain more loft, and dry out quicker than untreated down. While we couldn't verify their exact percentages, our anecdotal testing proved to us that this technology works. 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 ultralight bag for you.

Read Review: Marmot Phase 30


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.

A magnificent campsite  and a great place to test out the best ultralight sleeping bags and quilts. This is near the small village of Samdo on the Manaslu Circuit in Nepal  using the Palisade 30 and The North Face Superlight 15.
The Econ Burrow is a versatile  inexpensive quilt with quality features. It's such a good deal it was an obvious choice for the Best Buy on a Tight Budget Award.
With the hood tightened up as it is here  this bag felt a bit too short for our head tester  who didn't find it comfortable to use with the hood pulled over his head.

We put each of these bags through a rigorous battery of tests to assess both their measurable qualities, like weight, fill power, features, and absolute warmth. Then we evaluated the qualitative performance of each through field testing. We slept in each bag multiple nights at as close to the stated temperature rating as possible to test the claims made by the manufacturer. Multiple testers tried the bags, some who sleep hot, some who sleep cold, side sleepers, back sleepers, and our main tester who seems to rotate through the night like a rotisserie chicken.

Related: How We Tested Ultralight Sleeping Bags

Analysis and Test Results


To evaluate each bag and quilt as objectively as possible, we selected five metrics in which to measure each bag: Warmth, Weight, Comfort, Versatility, and Features. Because these metrics are not all equal, 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 -20-degree winter bag.

The Summerlite kept us warm and dry on a rainy overnight in the Canaan Mountain Wilderness.
The Summerlite kept us warm and dry on a rainy overnight in the Canaan Mountain Wilderness.

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 sacrified 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.

Related: Buying Advice for Ultralight Sleeping Bags

Ultralight vs. Traditional

What does it mean to have an "Ultralight" sleeping bag? Ultralight is a set of guiding principles, in order 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 15 ounces to 2 pounds, whereas our Backpacking Sleeping Bag Review has bags ranging from 1 to 3 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.

Hanging out to watch the sunset and eat dinner in the award winning Feathered Friends Flicker 40  on an overnight trip into the Uncompahgre Wilderness in Colorado.
Hanging out to watch the sunset and eat dinner in the award winning Feathered Friends Flicker 40, on an overnight trip into the Uncompahgre Wilderness in Colorado.

Value


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. This allows you to make an informed cost/benefit analysis of what's out there, and 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. If a less expensive sleeping bag does what you need, there's no reason to spend more than you have to.

Warmth


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, as 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 ultralight it is. Fortunately, the bags we tested 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. In order 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.

The Revelation 20 is the warmest one that we tested  and on a warm summer night  there was no need to fasten it up underneath us. Going light  Peter didn't even bother with a sleeping pad  and apparently slept all night with his headlamp on. Beware the power of the "sleep aids" legal in Colorado.
The Revelation 20 is the warmest one that we tested, and on a warm summer night, there was no need to fasten it up underneath us. Going light, Peter didn't even bother with a sleeping pad, and apparently slept all night with his headlamp on. Beware the power of the "sleep aids" legal in Colorado.

Temperature Ratings

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.

Letting the down uncompress before a night out in the Utah Hills. We recommend unpacking your bag well before crawling into it so that it has time to regain its loft (and therefore maximize its warmth).
Letting the down uncompress before a night out in the Utah Hills. We recommend unpacking your bag well before crawling into it so that it has time to regain its loft (and therefore maximize its warmth).

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.

Insulated Sleeping Pads and Quilts

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. Our Sleeping Pad review goes into detail explaining the R-value (how pads get a warmth rating). The higher the R-value, 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 of 2019

The Backcountry Quilt 700 kept us warm on all but the very coldest nights in Nepal  and we loved how comfortable and versatile it was.
The Backcountry Quilt 700 kept us warm on all but the very coldest nights in Nepal, and we loved how comfortable and versatile it was.

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 Patagonia 850, the Zpacks 20 Degree, and the Western Mountaineering Summerlite. The Patagonia and Western Mountaineering bags are hooded mummy bags that allow a nearly complete thermal envelope around the sleeper, keeping in as much warmth as possible. The Zpacks bag 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 Summerlite fluffs up to a warm 4-inch fill and is one of the toastiest bags we tested.
The Summerlite fluffs up to a warm 4-inch fill and is one of the toastiest bags we tested.

Weight


Next to warmth, weight is the second most important consideration when choosing an ultralight sleeping bag. If you are putting together a lightweight backpacking kit, then the models represented here are all great choices for getting your base weight down near 10 pounds or less. For those looking to go extremely ultralight, only the lightest of selections here should grab your attention. 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. 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 only insulation used 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.

A bunch of UL bags stuffed into their included stuff sacks. On the top  L to R: Patagonia  Sierra Designs  Revelation 20  Superlight 15 (discontinued)  Zpacks 20 degree. On the bottom  L to R: the two Feathered Friends  Katabatic Palisade  WM Highlite  and the Sea to Summit Ember II and Spark I (both discontinued).
A bunch of UL bags stuffed into their included stuff sacks. On the top, L to R: Patagonia, Sierra Designs, Revelation 20, Superlight 15 (discontinued), Zpacks 20 degree. On the bottom, L to R: the two Feathered Friends, Katabatic Palisade, WM Highlite, and the Sea to Summit Ember II and Spark I (both discontinued).

More sleeping bags in sacks. From left to right: Astralite  Flicker 40  Econ Burrow 20  Revelation 20  Backcountry Quilt 700  and Thylacine.
More sleeping bags in sacks. From left to right: Astralite, Flicker 40, Econ Burrow 20, Revelation 20, Backcountry Quilt 700, and Thylacine.

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. Since they retain their fully enclosed design with a hood, mummy bags are naturally heavier. They save weight by having more restrictive cuts and usually employing only a half-length zipper.

The Vesper 32 is impressively light and packable at 15 ounces  but the compression sack made concerning ripping noises when we tightened it down. Not an issue if you simply stuff this bag into the bottom of your pack sans sack.
The Vesper 32 is impressively light and packable at 15 ounces, but the compression sack made concerning ripping noises when we tightened it down. Not an issue if you simply stuff this bag into the bottom of your pack sans sack.

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 never did we add the weight of the stuff sack. Most impressive in this metric are the Western Mountaineering Highlite and the Thermarest Vesper 32 at a scant 15 ounces. Also very light is the Feathered Friends Vireo UL, a mummy style bag without a hood or zipper that features a 25F rating on the lower half and a 45F on the upper half. It is meant to be paired with a warm down jacket for ultimate comfort at a lighter weight.

Comfort


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.

Another issue was the width or girth. Our favorites were the roomiest, that allowed us to lie on our side or back, or squirm around between the two, without feeling like we were wrapped up in cellophane. Mummy bags are famous for being a bit claustrophobic and constrictive, but some, like the Feathered Friends Vireo UL proved to be plenty roomy. Quilts often feel more spacious and less constrictive because of their open cut, but paradoxically we found on a couple of different quilts that if it was attached to our pad, then it was too tight to lie on our side. Or, if it was a frigid night and we wanted to wrap ourselves up entirely, there just wasn't enough fabric to wrap all the way around us.

This Zpacks 20 Degree hoodless mummy bag was just long enough to comfortably wrap around our shoulders and cinch tight around our neck  for a pretty much perfectly comfortable fit.
This Zpacks 20 Degree hoodless mummy bag was just long enough to comfortably wrap around our shoulders and cinch tight around our neck, for a pretty much perfectly comfortable fit.

Secondary to the fit of a sleeping bag is the rest of the potentially annoying comfort considerations. These include minor details such as whether the drawcord strings reside in a place where they will continuously dangle in your face, whether the liner fabric of the bag is comfortable to the touch and slippery enough for clothes to slide around unimpeded inside, and whether hoods fit over the head comfortably. The presence of features that bothered us induced us to lower the comfort score a little bit.

For a mummy bag  we thought the design of the Patagonia 850 left a lot of room in the torso section  helping us avoid the feeling of claustrophobia that can be an issue with tighter mummy bags.
For a mummy bag, we thought the design of the Patagonia 850 left a lot of room in the torso section, helping us avoid the feeling of claustrophobia that can be an issue with tighter mummy bags.

Ultimately, one mummy bag and one quilt proved to be the most comfortable designs in this review. The Sierra Designs Backcountry Quilt 700 is supremely satisfying because it had no zippers, buckles, or drawcords to disturb your sleep. Instead, it is designed extra wide so that it comfortably wraps all the way around you like a flour tortilla, and extra tall so you could easily duck your head inside on a cold night, or use the unique hideaway hood feature. Alternatively, 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.

Comparing how comfortable everyone felt in a mummy bag (orange Patagonia 850) versus a quilt (blue Revelation 20) or simply brown fur  camping on the Dolores River in the spring.
Comparing how comfortable everyone felt in a mummy bag (orange Patagonia 850) versus a quilt (blue Revelation 20) or simply brown fur, camping on the Dolores River in the spring.

Versatility


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. Simply put, 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 resistant) 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.

On a chilly morning in the desert  we enjoyed the versatility of being able to wear the Flicker 40 with our feet out and the zipper done up  at least until the sun hit.
On a chilly morning in the desert, we enjoyed the versatility of being able to wear the Flicker 40 with our feet out and the zipper done up, at least until the sun hit.

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. Simply put, 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.

The Flicker 40 is one the quilts in the review that is capable of opening up fully into a blanket on warmer nights. It's wide enough for two people to fit under.
The Flicker 40 is one the quilts in the review that is capable of opening up fully into a blanket on warmer nights. It's wide enough for two people to fit under.

Tied near the top in the versatility department are the Zpacks Classic and the Sierra Designs Backcountry Quilt 700. 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. Using an opposite strategy, the Backcountry Quilt 700 is the most extensive and most expansive one person quilt with an enclosed foot box, ideal for summer comfort. Due to its size, it can wrap all the way around a person, providing an excellent cocoon in colder weather. It also uses hydrophobic DriDown to protect against condensation build up. 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.

One of the nice things about the Backcountry Quilt 700  and all quilts  is how easily they function as blankets to keep one warm while hanging out around camp.
One of the nice things about the Backcountry Quilt 700, and all quilts, is how easily they function as blankets to keep one warm while hanging out around camp.

Features


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. A good analogy would be a car. A car is a motorized vehicle that allows you to go somewhere without using your human power. Its features, like the stereo, air conditioning, and drivetrain, are what allows you to be comfortable and have fun while on your way. While not as critically important as warmth or weight, features are never-the-less the pieces of a sleeping bag that you will use every night that you sleep in it, so how well they perform is very important.


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.

The two-way zipper on the Patagonia 850 is a versatile feature that allows access to the mid-section and is ideal for managing tie-in points while climbing big walls or during alpine bivies. It is also handy for pulling the draw cords for the neck and hood that live on the outside of the facial opening.
The two-way zipper on the Patagonia 850 is a versatile feature that allows access to the mid-section and is ideal for managing tie-in points while climbing big walls or during alpine bivies. It is also handy for pulling the draw cords for the neck and hood that live on the outside of the facial opening.

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.

Showing how the hideaway hood feature on the Backcountry Quilt 700 works. Essentially it is a gap in the fabric that you stick your face through. A down stuffed baffle now becomes a pillow  and the rest of the quilt wraps easily around the face and upper shoulders. Despite its odd design  we found it was comfortable and worked really well to keep us warm.
Showing how the hideaway hood feature on the Backcountry Quilt 700 works. Essentially it is a gap in the fabric that you stick your face through. A down stuffed baffle now becomes a pillow, and the rest of the quilt wraps easily around the face and upper shoulders. Despite its odd design, we found it was comfortable and worked really well to keep us warm.

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 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.

A warm night in the Black Canyon was a great excuse for Cowboy camping in the Katabatic Gear Palisade 30. We loved the adjustability of the pad attachment straps on this pleasant evening.
A warm night in the Black Canyon was a great excuse for Cowboy camping in the Katabatic Gear Palisade 30. We loved the adjustability of the pad attachment straps on this pleasant evening.

Conclusion


There's a lot out on the market these days in the world of sleeping bags, from square cut behemoths to dainty featherweight quilts, and a whole lot in between. In this review, we were specifically looking for ultralight sleeping bags, as more people want to go further, and harder, with less weight on their backs. Ultralight sleeping bags are best suited for warmer temperatures, but with proper planning and well-designed systems, 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, fast packing, 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