The Best Ultralight Sleeping Bags of 2018

Waking up to a chilly morning after sleeping out in the San Juan Mountains. The Vireo  in blue  and the HighLite in purple.
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If you're on a mission to cut as much weight from your backpacking gear as possible, your sleeping bag is an excellent place to start. We studied over 50 ultralight options and purchased the 12 best for our side-by-side tests. Our expert testers spent hundreds of nights in these bags in remote corners of the globe, from the Rockies to the Himalayas. We used them in various conditions and elevations, and then carried them all on our backs during the day. We evaluated them on their comfort and warmth and picked out some favorites for you below. Whether you are a gearing up for a multi-month thru-hiker 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.

Read the full review below >

Test Results and Ratings

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Analysis and Award Winners


Review by:
Andy Wellman
Senior Review Editor
OutdoorGearLab

Last Updated:
Tuesday
April 10, 2018

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Updated April 2018
We're constantly scouring the market checking for new or improved options to add to our review. Marmot recently overhauled their performance line, and we tried out the Phase 30, which after testing took home our Top Pick for Water Resistance. We were also excited to check out Patagonia's new line of bags, and we gave their 850 our Top Pick if you're looking for a mummy bag. We also have a new recommendation for those on a tight budget who need something for warmer weather: the Kelty Cosmic Down 40. None of these contenders could quite match the Feathered Friends Flicker 40, which retains its top spot as our Editors' Choice winner (see review below).

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 was the highest rated bag in our review. 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 UL 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. The lack of a hood also makes it less warm on cooler evenings — check out the 30F and 20F options if you want a little extra warmth for only a bit more weight. We did 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 was 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

Best Bang for the Buck


Enlightened Equipment Revelation 20


Best Buy Award

$285 List
List Price
See It

Weight: 18.5 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
While not quite as high scoring as our Editors' Choice winning Feathered Friends Flicker 40 UL, the Enlightened Equipment Revelation 20 retails for a lower price of $285. If price is your primary consideration, it is hard to find an ultralight sleeping bag that offers anywhere near as much versatility or warmth as this bag, without overly burdening the budget. Enlightened Equipment provides perhaps the most highly customizable sleeping bag you could ask for, which is fantastic for people with who are extra tall or wide, want more or less insulation, or are very particular about color choices. For this review, we chose this non-customized "off the shelf" model, which ships immediately upon order instead of waiting for a custom bag to be constructed.

If you do want a custom-made option, expect to wait 2-4 weeks for shipment, so give yourself ample time before your next trip. We tested the standard size, and it felt a little constricting when entirely closed up, so if you are even a little bit on the broad side, we'd recommend a custom cut. There's a lot of dangling cords as well, which was annoying at times. Other than that, we liked everything else about the Revelation 20. It's a highly versatile quilt that is also very warm, and it ranked in the top half of the products we tested. It's not the cheapest model in this review, but it did offer the best value, with a high overall performance score and a lower-than-most price tag.

Read review:Enlightened Equipment Revelation 20

The Best Ultralight Mummy Bag


Patagonia 850 Down 30


Patagonia 850 Down Sleeping Bag 30 Top Pick Award

$399.00
at Patagonia
See It

Weight: 26.2 oz | Fill: 850 fill Traceable Down
A fully enclosed mummy bag with hood
Spacious and non-constricting
Very warm for the rating
Heavier than most
Half-zip makes it challenging to ventilate
As one of the highest rated ultralight sleeping bag we tested, the Patagonia 850 Down 30 deserves recognition as the best fully enclosed hooded mummy bag. While quilts may offer greater versatility or options for venting, when it comes to hunkering down outside on a cold night, nothing beats the tight wrap and over-the-head protection of a hooded mummy bag. As one of Patagonia's first generation of sleeping bags, we are pleasantly surprised that they managed to create such an excellent product on their first try — hats off! It is well-designed with functional features, such as a two-way zipper, hidden cord-lock release buckles, and a more spacious foot box.

While it is on the heavier side compared to the competition, it was also one of the warmest bags we slept in, despite only coming with a 30F rating. There's only has a half zipper though, making it harder to ventilate on warm nights and unable to open up fully like the quilts can. But, if you're looking for a light, toasty, and snuggly mummy bag, this is an ideal option.

Read review:Patagonia 850 Down Sleeping Bag 30

Top Pick for Water Resistance


Marmot Phase 30


Top Pick Award

$319.16
at Backcountry
See It

Weight: 18.3 oz | Fill: Certified 850 fill with Down Defender treatment
Combination of Pertex fabric and Down Defender treated insulation makes it supremely water resistant
Very lightweight for a fully hooded mummy bag
Full-length zipper allows easier ventilation than most mummy bags
Not nearly as warm as its rating suggests
Zipper has an annoying habit of snagging on draft tube fabric
Looking to go ultra-light, 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's 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

$298.95
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 (!) in the included compression stuff sack
Low 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

Notable for Those on a Tight Budget


Kelty Cosmic Down 40


Cosmic Down 40
$91.04
at Amazon
See It

Weight: 31 ounces | Fill: 600 fill DriDown
Inexpensive
Easy to find
No custom ordering
Not that warm, lower quality 600-fill down
Heavy for an ultralight bag
Most ultralight backpackers will scoff at the Comic Down 40. We did as well until we used it. While not as high-performing as the other models, it still works! We tested it in the High Sierra at 11,000ft where it got down to 30 degrees at night, and we stayed warm enough when we kept our hat, thermals, and down jacket on at night.

It's not as light as the other ultralight options (almost 2 pounds), but we've included here for people that are on a very tight budget or only backpack once a year, and want something that costs $120 or less. The expensive gear in the review is often high-quality and worth it if you backpack a lot. But if you're just getting into traveling fast and light, we don't think money should keep you from diving in. Products like the Cosmic Down 40 fit that need.

Read review:Kelty Cosmic Down 40

Best Warmth to Weight Ratio


ZPacks Classic


ZPacks 20 Degree
$379 List
List Price
See It

Weight: 20.3 oz | Fill: 900 fill
Warm!
Simple design
Customizable
Constricting
Small foot box
Poor neck drawcord

For one ounce more than our Editors' Choice winner, the Feathered Friends Flicker 40 UL, you get 20 degrees more comfort rating from the ZPacks Classic. Made with 900 fill down, it doesn't get much loftier for the weight than this. It compresses down to a tidy package, and we loved the included roll-top waterproof stuff sac.

This wasn't the perfect bag - we found it a little constricting and cut on the narrow side, but it is customizable and available in a wider girth. It doesn't open up to a full quilt like other UL bags, limiting its versatility a little particularly in warmer conditions. There's no hood either, so we slept about as warm in the Classic as we did in the 30F-rated Patagonia 850 which does have a hood. If you're setting off on a thru-hike and need something that can take you through the Sierra in the early spring, this bag is an excellent choice and a great way to get your base weight down under 10 pounds while still keeping you toasty at night.

Read review: ZPacks Classic

select up to 5 products
Score Product Price Our Take
72
$339
Editors' Choice Award
Won our Editors’ Choice Award because it had the best performing set of features that allowed for the most versatile usage.
70
$379
With an enclosed foot box and ¾ length zipper, this warm hoodless mummy can also be used quilt style…
69
$285
Best Buy Award
Offers the versatility of sleeping under it as a blanket or fully wrapped up, with a huge range of customizable options.
69
$400
Top Pick Award
When you want a fully enclosed mummy bag with a hood, but don’t want to carry a ton of extra weight, this is your bag…
69
$399
Top Pick Award
A great choice for those who want the lightest bag they can get but still want a fully un-zip-able mummy bag.
67
$329
The only mummy bag that uses more down fill in the foot box and less around the torso, to take advantage of the clothing you have with you.
64
$300
Top Pick Award
Packing down to the size of half a Nalgene, this sleeping bag is great for bike touring or bike packing, as well as summer time backpacking.
63
$470
A warm, lightweight, small packing quilt that takes more work, but attaches more securely to a pad than any other quilt…
63
$250
This unique quilt design has no straps or zippers of any sort, but is large enough to completely wrap around oneself like a burrito.
55
$350
This is a hooded mummy bag we wanted to love, but compared to the competition it simply didn’t stack up.
33
$250
We wouldn’t recommend this quilt for pretty much any reason, and think it needs to be sent back to the design lab.

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'll explain why each testing category is essential to consider when making a purchase and how we tested for that parameter. Then we'll 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 features, materials, and the buying process.

Ultralight vs. Traditional
What do we even mean when we say an Ultralight sleeping bag? These are models that prioritize weight savings and compressibility over warmth and features. Many are "quilts," or can become quilts, the thought being that the down under you in a regular sleeping bag is not doing much to keep you warm, so why carry it? They might not look like a traditional mummy bag, or have a hood. They also assume that you can stretch the comfort rating of each one with clothing that you are already carrying, like a puffy jacket. The models in this review range in weight from 12 ounces to just under 2 pounds, and in our Backpacking review they range between 1 and 3 pounds. A subtle difference for sure, with some crossover as well. Be sure to check both comprehensive guides out if you are on the fence about which way to go.

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 component we talk a lot about in our reviews (but don't score for) is value. How much bang for your buck are you getting from your purchase? Considering all of the different products you have to purchase for backpacking or other remote camping activities, buying great, but not too expensive, products can save you hundreds, if not thousands of dollars, without compromising your comfort or safety on the trail.

The chart below shows you how each product scored in our metrics relative to their price. This can help you winnow out the ones that have a hefty price tag without a comparable increase in performance, and it can also help you find something that offers a lot of value for its price. Bags that fall to the bottom right of the graph have a high score relative to their price, including the Sierra Designs Backcountry Quilt 700 and the Sea to Summit Spark I. Not surprisingly, this is also where our Best Buy winner, the Enlightened Equipment Revelation 20 also lands. While a higher price tag often correlates with better performance due to advanced materials used in construction, know that you don't always have to break the bank to get a good product.


Warmth


Getting a good night's sleep is key to enjoying your overnight outdoor adventures, and warmth plays a critical role in making that happen. More importantly, though, warmth is important for your safety. In the quest to lighten your load for comfort and speed, compromising on warmth is just not an option. If your ultralight sleeping bag, paired with your warm clothing, does not keep you warm enough to sleep well and recuperate from your big day of hiking, climbing, or bike riding, well, it doesn't matter how little it weighs. Fortunately, the innovative bags we test here deliver excellent warmth-to-weight ratios. We strongly believe that you should choose your warmth based on the weather you will encounter, and our warmth ratings contribute 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. 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. The type of baffles (sewn-through vs. box baffle) impacts how many 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?

It turns out there is only one standard for sleeping bag temperature ratings, the EN 13537 standard. To qualify for this standard test, a sleeping bag must have a hood, which rules out all but four of the bags in our test. For those that get a standard EN rating, there are two ratings — comfort and lower limit. In most cases, manufacturers publish the lower limit rating number, as was the case with the two bags we froze in, but without stating as such. It is true that we didn't freeze to death that night, so the bags did perform to their tested lower limit, but hidden on their websites was the (real) helpful information that these bag's comfort ratings were in the upper 20's, a fact we didn't know. 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
Most of the quilts we tested are not designed to enclose the person inside of them fully and are instead meant to wrap around one on the top and attach to a sleeping pad underneath. The idea is that if the down underneath a person is compressed, it will not provide warmth-trapping loft, so why not save the weight if it won't be used effectively? In theory, this is a smart move, but for it to work, you must take into consideration the R-value and insulating properties of your sleeping pad. Since your sleeping pad now forms a very critical part of your warmth envelope, it needs to be insulated. Check out our Sleeping Pad Review and look particularly at the R-value of the pad, higher is better. During our testing, we found that on some cold nights, even an insulated sleeping pad was not enough to keep us warm with a quilt, and so we would have appreciated the extra weight and insulation beneath us.

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 was the Zpacks Classic, a hoodless mummy featuring 900 fill down 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. While we love quilts for their versatility and spaciousness in warmer weather, our testing revealed that in cold weather, they don't seal off well and can't keep us as warm as mummy style bag.

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. 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.

All of the ultralight sleeping bags in this review 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! The majority of these are smaller than a similar Traditional Mummy Bag. On the top  L to R: Patagonia  Sierra Designs  Revelation 20  Superlight 15  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.
All of the ultralight sleeping bags in this review 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! The majority of these are smaller than a similar Traditional Mummy Bag. On the top, L to R: Patagonia, Sierra Designs, Revelation 20, Superlight 15, 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.

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, our Top Pick for 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 cover 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 when included, 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 was supremely satisfying because it had no zippers, buckles, or drawcords to disturb your sleep. Instead, it was 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 was the most comfortable mummy bag due to its generous sizing around the torso, the deep fitting hood, and a unique foot box design that was 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 three was 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 was the Feathered Friends Flicker 40 UL. Made with the lightest and highest quality 950+ fill goose down, 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 was 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 DryDown to protect against condensation build up. Our favorite choice for battling wet weather was the Marmot Phase 30, which included 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 Award-winning Feathered Friends 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 was a game-changer for trapping in heat.

The Patagonia 850 Down Sleeping Bag 30 also had 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 Bang for the Buck Award-winning Enlightened Equipment 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 are hundreds, if not thousands, of sleeping bags available on the market today to choose from, ensuring it is a challenging task to find the right one. This review specializes in ultralight sleeping bags, specially designed to be as light as they can be. Ultralight sleeping bags are ideal for use in the summer and depending on the climate and your sleeping system, hopefully, spring and fall as well. They are great for outdoor sports like thru-hiking, fast-packing, bike-packing, bike touring, trekking, adventure racing, alpine climbing, and any situation where weight and pack size is of critical importance to the success of the adventure. We chose these as the best and most popular 12 sleeping bags out of literally hundreds of options, and then tested them extensively in the mountains and deserts all over the world, often in quite cold temperatures, in order to provide you with the most comprehensive comparative review available today. We hope that this article, used in conjunction with the individual product reviews and our Buying Advice Article, helps you to make a purchase the suits your particular needs.
Andy Wellman

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