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

The Best Ultralight Sleeping Bags

Waking up to a chilly morning after sleeping out in the San Juan Mountains. The Vireo  in blue  and the HighLite in purple.
By Andy Wellman and Ethan Newman
Thursday November 1, 2018
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Ready to drop some pack weight for your next backpacking venture? We studied over 50 ultralight sleeping bags and purchased the 14 best mummy bags and quilts for our side-by-side tests. Our expert, thru-hiking 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 getting into backpacking for the first time, we have some great recommendations for you. We also have a more traditional Backpacking Sleeping Bag review, for those needing warmer options for cooler climates.


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Awards Editors' Choice Award Best Buy Award  Editors' Choice Award Top Pick Award 
Price $339.00 at Feathered Friends$285 List$379 List$378.53 at Amazon
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$398.95 at Backcountry
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Pros Highest scoring ultralight sleeping bag, best features, and most versatileVery affordable, highly customizable, versatile, lots of featuresWarm for an ultralight bag, simple and versatile design, box baffle construction, waterproof stuff sackWarm, tons of high quality down, water resistant, great anti-snag zipperWarmer 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 strapsA little constricting, small foot box, not the best neck draw cord designExpensive, underneath side of bag uses sewn through construction, weight, fragileMore 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.The warmest quilt in our review also comes at an reasonable price.A top-scoring bag that's warm and versatile enough for full three-season use, while weighing impressively little.18 ounces of 900 fill-power Q.Shield down equals a winning combination!A high-quality hooded mummy bag that is significantly lighter than a standard backpacking bag.
Rating Categories Flicker 40 UL Revelation 20 ZPacks Classic Ghost Whisperer 20 Marmot Phase 30
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Specs Flicker 40 UL Revelation 20 ZPacks Classic Ghost Whisperer 20 Marmot Phase 30
Style Center zip mummy bag or unzipper to be quilt Quilt Hoodless mummy Hooded mummy Hooded Mummy
Manufacturer Stated Temperature Rating 40F 20F 20F 20F (EN Comfort = 32F) 30F (EN Comfort = 42F)
Measured weight, bag only (ounces) 19.1 oz 20.9 oz 20.3 oz 26.5 oz 18.3 oz

Updated November October 2018
We are always looking to keep our reviews updated with the best and most innovative options on the market. Most recently we tested the Astralite from Western Mountaineering, one of two models in their foray into the ultralight quilt market. We also retested the Enlightened Equipment Revelation 20 with the 2018 updates, which kept its Best Buy Award for the third straight year in a row, and the newly updated Sierra Designs Backcountry Quilt 700, which now comes in two temperature ratings. The Econ Burrow, after thorough testing and reviewing, became our favorite for those on a tight budget. Still, the Feathered Friends Flicker 40 UL stays the winner of the Editors' Choice Award. Check out the reviews below for more info.

Best Overall Ultralight Sleeping Bag


Feathered Friends Flicker 40 UL


Editors' Choice Award

$339.00
at Feathered Friends
See It

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 quite as toasty. Check out the 30F and 20F options if you want a little extra warmth for only 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 was 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 Mummy Bag


Mountain Hardwear Ghost Whisperer 20


Editors' Choice Award

$378.53
(34% off)
at Amazon
See It

Weight: 26.5 oz | Fill: 900 Fill Q.Shield Treated Down
A fully enclosed mummy bag with hood
Comfortable, spacious, and warm
Superior loft from 18 ounces of 900-fill RDS sourced down
Heavier than most
High price

When it comes to going ultralight, less is more. Less weight and less bulk equal less time and less effort. But if you look closely at UL sleeping bags, you may find that sometimes less is less. Less weight means less insulation, less fabric, fewer features, and (gasp) less warmth. That may be fine if you are spending a single night out during the peak of summer, but what if you still plan to backpack in the spring and fall when nights are cold, love camping at 12,000 ft. in Colorado, or simply sleep cold every night regardless? Then you may be a perfect candidate to ignore all the hype surrounding quilts and instead stick with a classic mummy bag. Check out our Editors' Choice Mummy Bag — the Mountain Hardwear Ghost Whisperer 20. While still weighing in at significantly less than two pounds, this top quality bag features a whopping 18 ounces of heat-trapping insulation, provided by the highest quality 900 fill power down that is both certified responsibly sourced and comes treated with Q.Shield to make it water resistant. It's toasty.

Of course, everything comes at a price, and in the case of the Ghost Whisperer 20, that cost is the hit to your wallet. Rest assured, this is a really nice sleeping bag, but saving a bunch of weight while still sleeping comfortably below freezing isn't going to come cheap. Luckily, there is also a 40F version that is significantly lighter for a price that is more in line with the rest of this review. Regardless, the Ghost Whisperer 20 is a delightfully warm and comfortable mummy bag that will serve you well on those adventures when a quilt won't cut it.

Read review:Mountain Hardwear Ghost Whisperer 20

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 judgement is that your needs supercede any one else's opinion on the matter. If you want more information on this topic, our Buying Advice article digs into the advantages and drawbacks of each type of design.

Best Bang for the Buck


Enlightened Equipment Revelation 20


Best Buy Award

$285 List
List Price
See It

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, its 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 the very reasonable price of $285 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, as custom quilts 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 great 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

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

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

Top Pick for Extreme Packability


Sea to Summit Spark I


Sea to Summit Spark SP I
Top Pick Award

$191.37
(36% off)
at Backcountry
See It

Weight: 12.7 oz | Fill: 850+ loft Ultra-Dry Down
Lightest bag in this review
Packs down to the size of a softball
Fair price
Only suitable for warm, summer use
Minimal down loft

For certain activities, like self-supported bike touring, bike packing, fast-packing, or adventure racing, weight and size are simply the most important characteristics of any, and every, piece of gear. That's why we couldn't help but recognize the Sea to Summit Spark I as the lightest and smallest down sleeping bag we have ever seen! At a measly 12.7 ounces, this thing weighs less than a jacket, and stuffs into an included compression sack the size of a softball!

Of course, a sleeping bag so small and light comes with obvious drawbacks, such as a comfort rating of 54F, meaning it's only suitable for warm summer nights (or by those willing to suffer a little bit for its attributes). It also costs as much as other bags in this review ($300), but is less versatile, meaning you'll need another one for colder temps. But, if you're a fair weather camper only, or want a dedicated summer bag that packs so small it's almost a joke, the Spark is hard to beat.

Read review:Sea to Summit Spark I


Analysis and Test Results


We put each of the models in this review to the test in a wide variety of conditions to help you figure out which is the best one for your needs. We rated each bag on a scale of one to ten for five separate metrics: warmth, weight, comfort, versatility, and features. We weighted each metric according to the relative importance that we deemed it had in overall performance, and each product ended with a cumulative score between 1-100. In all cases, we assigned scores based on comparisons between the products, so the highest scoring sleeping bag for a given metric was the best compared to the rest in this review, and not compared to the sleeping bag market as a whole. Keep that in mind particularly when looking at our warmth scores, as we are comparing the warmth of these products (20F to 54F comfort ratings) to each other, and not to other bags that are made to withstand 20-below temps.

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.
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.

Below we discuss each rating metric in depth. We explain why each testing category is essential to consider when making a purchase and how we tested for that parameter. Then we note the standout models for each category, and also the ones that didn't impress us that much. Ultralight sleeping bags have some advantages over regular backpacking models but often suffer from some serious disadvantages as well. For this reason, we recommend that you thoroughly research and understand a product's relative merits and weaknesses by checking out their individual reviews as well before making a purchase. We also have a comprehensive Buying Advice article, which goes into much greater detail about ultralight sleeping bag types, features, materials, and the buying process.

Ultralight vs. Traditional
What does "Ultralight" even mean? When it comes to sleeping bags, it means prioritizing saving weight and size, sometimes at the cost of warmth and comfort. Some of these bags achieve a low weight by a smaller cut, or a lighter fabric, or stretching the idea of "warmth" to the limit. Many of the bags in this review are quilts, the idea being that the down and fabric under your body isn't doing anything, so why not get rid of it? Many of these bags don't look like a traditional mummy bag or even have a hood. They also assume these bags will be used as part of a sleep system, including a quality insulated pad and warm clothing you're already carrying. The bags in this review span from as little as 12 ounces to just over 2 pounds, whereas in our Backpacking Sleeping Bag review, they range from 1 to 3 pounds. It's not a huge difference for some, but ultralight folks count ounces, not just pounds. Make sure to check out both reviews if you're not sure which category is right for you.

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 hundreds, if not thousands of dollars, without compromising performance in the backcountry.

Comparing value and performance level together helps to eliminate options that cost more without additional benefit. A common trade-off in this category is the weight and price balance. Top-notch goose down with a high fill power generally leads to a great warmth-to-weight ratio (note — construction and design also play large roles in effective warmth) but also inflates the price compared to duck down-filled bags. Higher prices often mean superior performance due to better quality materials and construction, but not always. And sometimes a small improvement in performance isn't worth hundreds of dollars. We want you to make sure you're getting the best product for your money. If a less expensive bag handles everything you plan on throwing at it, there's no reason to spend more on another model.


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 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.


The amount of loft, or the heat-trapping space created around you by the down fill of your bag, is the primary determining factor of how warm a sleeping bag will be. In this review, we've only tested down bags because down is superior fill for both a warmth-to-weight ratio. To build loft while adding the least amount of weight, the majority of these bags use very high quality down with high fill powers. Secondary to the loft is construction. To prevent the down from moving around inside the bag, manufacturers sew in baffle patterns that create little chambers to trap the down in place and prevent it from moving about; although some bags have designs to allow some strategic down movement, like shaking more down into the foot box. The type of baffles (sewn-through vs. box baffle) impacts the number of thin spots where very little or even no down protects you from the chill outside. Additionally, the shape of the baffles is different on every bag, and some are more effective than others at preventing "dead spots" and keeping the down in place.

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

All 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.

This is the amazingly light Spark I. With only 6 ounces of down filling  there are bound to be gaps. Held up to the light it is obvious that there are limits to how far one can really make this little insulation go.
This is the amazingly light Spark I. With only 6 ounces of down filling, there are bound to be gaps. Held up to the light it is obvious that there are limits to how far one can really make this little insulation go.

While down is the insulation that traps the warmth and keeps out the cold, we found while testing these bags in frigid temperatures that little design features can make a huge difference in how warm or chilled we felt. Features like hoods, draft collars around the neck, zipper baffles, enclosed foot boxes, and mummy vs. quilt design can have a significant impact on how warm we felt inside a bag, regardless of the amount of loft. In general, traditional hooded mummy bags allowed us to burrow deeper inside our bag and stay warmer than bags without hoods. Likewise, despite their versatile and freedom granting designs, quilts inevitably permitted openings where cold air could squeeze in and were thus rarely as warm feeling as a mummy bag.

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. 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.Check out our Sleeping Pad Review and be sure to pay attention to 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.

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. At the top of the warmth department is the Mountain Hardwear Ghost Whisperer 20, a hooded mummy with a comfort rating of 32F and box baffle construction. The Patagonia 850 Down Sleeping Bag 30 is a full-hooded mummy that uses very thick but narrow sewn-through tube baffles, and it also scored highly. Another high scorer was the Zpacks Classic, which featured a ton of loft in its box baffles, but lacked a hood. 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.

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 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 table or on the individual product pages.

A bunch of UL bags stuffed into their included stuff sacks. Notice how tiny the Spark I is on the bottom right -- no wonder we gave it a Top Pick Award! 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.
A bunch of UL bags stuffed into their included stuff sacks. Notice how tiny the Spark I is on the bottom right -- no wonder we gave it a Top Pick Award! 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.

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 cuben fiber roll-top waterproof stuff sack that came included with the 20 Degree was a real hit  and was  without a doubt  the best stuff sack we used during this review. Zpacks also sells these sacks on their own  and we would recommend one for all sleeping bags.
The cuben fiber roll-top waterproof stuff sack that came included with the 20 Degree was a real hit, and was, without a doubt, the best stuff sack we used during this review. Zpacks also sells these sacks on their own, and we would recommend one for all sleeping bags.

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. The lightest bag in this review is the Sea to Summit Spark I, a Top Pick for its insane packability. It weighs in at a remarkably low 12.7 ounces and packs into an included compression stuff sack the size of a softball. Second is the Western Mountaineering HighLite, a hooded and fully enclosed mummy style bag that manages to weigh a measly 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.

The stuffed Spark I on the left in its included compression sack  smaller than a Nalgene! On the right is the Flicker 40  which is also really small inside its stuff sack  just not by comparison!
The stuffed Spark I on the left in its included compression sack, smaller than a Nalgene! On the right is the Flicker 40, which is also really small inside its stuff sack, just not by comparison!

Comfort


In many ways, comfort is the quality of a sleeping bag that makes it unnoticeable. Think about it, discomfort while sleeping usually has to do with something that is bothering you. If there is no tightness constricting you, rough fabric itching you, drawcords dangling in your face, or buckles resting underneath your body, then there will be nothing causing you discomfort, and you will be comfortable. Quality sleep is one of the most important aspects of a successful backcountry trip, as you need to be able to recover after long days of difficult hiking, biking, climbing, or whatever it is you are doing. Since comfort is so important, we chose to weight it as 20% of a product's final score.


When assessing for comfort, the first thing we looked at is how well the bag fits. Our head tester is 5'11" 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 wasn'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, we found that quilts were 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 that included full-length zippers, or 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 of three quilts in the review that was capable of opening up fully into a blanket on warmer nights. It was the widest or those three  big enough for two people to fit under.
The Flicker 40 is one of three quilts in the review that was capable of opening up fully into a blanket on warmer nights. It was the widest or those three, big enough for two people to fit under.

Tied for second 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, a perfect 10. 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 Sleeping Bag 30 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 is a plethora of sleepings bags and quilts available these days, from voluminous square cut bags to featherlight quilts, and everything in between. This review specifically inspected ultralight sleeping bags, as there's a growing market for lighter gear to take us further into the remote parts of the world. Ultralight sleeping bags and quilts are ideal for warmer temperatures, and depending on conditions and the overall sleep system, into the shoulder seasons of spring and fall. These bags are designed for any multi-day activity where carried weight is a major limiting factor: thru-hiking, fast-packing, bike-packing, bike touring, trekking, adventure racing, alpine climbing, and other fast-and-light wilderness travel. We looked through hundreds of options to find the best and most popular sleepings bags and tested them on cold nights all over the world, from high mountain valleys to desert canyons, to give you the most comprehensive comparative review out there. We hope this article, our product reviews, and our Buying Advice Article help you find the option that suits you best.


Andy Wellman and Ethan Newman