
iRunFar’s Meghan Hicks has been using the Western Mountaineering HighLite for warmer weather trips for years, sometimes pushing it into cooler temps by utilizing a puffy and a bivy. Photo: iRunFar/Eszter Horanyi
A sleeping bag is one of the most important pieces of gear when assembling a fastpacking or ultralight backpacking kit. Without a good night of sleep, trips can become miserable quickly, and if you spend the dark hours shivering, you’re probably not sleeping well. The best ultralight sleeping bags will keep you warm without weighing you down.
Whether you’re looking for an ultralight sleeping bag for mild desert nights or one that will keep you warm above treeline on a late fall trip, the weight of the bag matters. When combined with a slimmed-down kit, the best ultralight sleeping bags will keep your backpack light, allowing you to run on many types of terrain and move quickly and efficiently at other times.
For this guide, we researched and tested over 25 sleeping bags over the course of several years. We took them on spring, summer, and fall trips in the San Juan Mountains of Colorado, shoulder-season trips through the deserts of the Colorado Plateau, and countless trips through the Wasatch Mountains of Utah. We also tested sleeping bags in the damp climate of New Zealand, where keeping gear dry was a key challenge.
The sleeping bags in this guide are all light, warm, durable, comfortable, and packable. If you’re looking for one hooded bag that can do it all, we recommend the Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree. If you prefer a quilt, we loved the Katabatic Gear Alsek 22F Quilt for its lightweight warmth. And if you’re looking for a hooded sleeping bag for warmer temperatures or want to shave grams off your kit, consider the Western Mountaineering HighLite, which weighs only 16 ounces.
For more background information, see our buying advice, testing methodology, and frequently asked questions below the picks.
Make sure to check out our best fastpacking packs, best ultralight tents, best ultralight sleeping pads, and best ultralight backpacking gear guides as well!
Best Ultralight Sleeping Bags
- Best Ultralight Sleeping Bag With a Hood: Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree
- Best Ultralight Sleeping Bag With a Hood — Runner-Up: Montbell Seamless Down Hugger 800 #2
- Best Ultralight Sleeping Bag Without a Hood: Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree
- Best Ultralight Sleeping Bag Without a Hood — Runner-Up: Zpacks Classic Sleeping Bag – 20F
- Lightest Ultralight Sleeping Bag: Western Mountaineering HighLite
- Lightest Ultralight Sleeping Bag — Runner-Up: Sea to Summit Spark Down Sleeping Bag – 30F
- Best Ultralight Quilt: Katabatic Gear Alsek 22F Quilt
- Best Ultralight Quilt — Runner-Up: Enlightened Equipment Convert Sleeping Quilt – 20 Degree
- Best Budget Ultralight Quilt: Outdoor Vitals StormLoft Down TopQuilt 15

The iRunFar team tests sleeping bags in all sorts of locations and temperatures. Photo: iRunFar/Eszter Horanyi
Best Ultralight Sleeping Bag With a Hood: Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree ($660)
Pros:
- Comfortable
- Extremely warm
- Dimensions fit all testers well
Cons:
- Expensive
- Minimal draft collar
The Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree is the warmest sleeping bag we tested. At 27 ounces, it is just barely light enough to qualify as a fastpacking sleeping bag. It features light, durable, downproof fabrics and is packed with 16.8 ounces of 950-plus fill down.
We slept in this bag on several fastpacking trips in temperatures ranging from 22 to 45 degrees Fahrenheit. Even at 22F, we didn’t feel like we were approaching the lower limit for this bag. It’s warm.
One downside to this bag is that it lacks an actual draft collar. To keep the cold out, you have to cinch the opening fairly snugly around your face. Draft collars give us the option of leaving the opening uncinched on cold-but-not-too-cold nights, which we think would be more comfortable.
Several of our female testers were happy with this sleeping bag’s 60-inch shoulder width. We believe the Swallow UL 20/30 is a truly unisex sleeping bag, fitting a range of bodies better than other wider and narrower bags. It’s also just insanely warm. This sleeping bag is on the more expensive end of the spectrum, but if you’re someone who spends a lot of nights out in the wild and can afford the price tag, we believe it’s a worthwhile investment that will last you a long time if properly cared for. The combination of features in this bag has led us to include it in our Best Ultralight Backpacking Gear guide.
The 20F version is so warm that we were able to push it into the shoulder season. This sleeping bag also comes in a 30F option for those who fastpack in warmer climates and want to save a couple of ounces compared to the 20F option.
Type: Hooded Mummy Bag | Actual Weight: 27.0 ounces (764 grams) | Fill Weight: 16.8 ounces (476 grams) of 950-plus fill | Temperature Rating: 20F | Packed Size: 7 x 12.5 inches (17.8 x 31.75 centimeters), 9 liters
Shop the Feathered Friends Swallow UL 20/30 Sleeping Bag - 20 DegreeBest Ultralight Sleeping Bag With a Hood — Runner-Up: Montbell Seamless Down Hugger 800 #2 ($455)
Pros:
- Lightweight
- Reasonable price
- Fewer seams improve thermal efficiency
- Nice draft collar
Cons:
- Less loft than other options
For several years, the Montbell Seamless Down Hugger 800 #2 has been a go-to option for multiple members of the iRunFar testing team due to its warmth-to-weight ratio and somewhat lower price point. This 25-degree Fahrenheit bag has a unique baffle-free design and weighs 22.7 ounces in size regular.
Instead of using baffles to keep the down from shifting around and clumping up, Montbell uses threads of yarn to create something resembling a spiderweb inside the bag that traps the 800-fill down where it belongs. The brand claims this increases its ability to loft while preventing it from moving around in the bag. The design also reduces the number of seams in the bag. Since seams are one of the major points of heat loss, this design increases the warmth of this sleeping bag.
This bag seems a viable option well below its temperature rating, especially if you wear a layer or two for sleeping. The 10-denier Ballistic Airlight nylon taffeta shell doesn’t feel scary-light and has withstood multiple summers and shoulder seasons of use without any sign of wear. We also haven’t noticed any down leaking out.
The draft collar seals in warmth, and you can cinch the hood for the warmest setup. A draft tube along the zipper also prevents heat loss. The bag’s tapered shape makes it thermally efficient, yet still provides enough room to stretch out the legs after a big day.
While both of our testers for this bag were women in the mid-five-foot range, Montbell claims it will accommodate a person up to six feet tall. A long version is also available for taller people or those wanting extra space.
While this sleeping bag doesn’t loft quite as much as the Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree reviewed above, it’s still very warm. At a significantly lower price, it’s an excellent option for those looking for something that will keep them warm on nearly any summer mountain or shoulder-season desert trip.
Type: Hooded Mummy Bag | Actual Weight: 22.7 ounces (644 grams) in size regular| Temperature Rating: 25F | Packed Size: 5.9 x 11.8 inches (15 x 30 centimeters), 4.7 liters
Shop the Montbell Seamless Down Hugger 800 #2Best Ultralight Sleeping Bag Without a Hood: Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree ($560)
Pros:
- Very light
- Conservative temperature rating
- Comfortable
- Tapered mummy shape is thermally efficient
- Opens into a blanket
Cons:
- Expensive
Our testers agree that the Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree can be used comfortably in a wider range of temperatures than any other sleeping bag on this list. Its versatility is just one of the many things that we loved about it. Hoodless sleeping bags are great for people who are going to fastpack with a hooded down jacket or a warm hat and don’t need extra warmth around their head.
The full-length zipper, which allows this sleeping bag to open into a blanket, makes it useful for both cold- and warm-weather trips. It features a drawstring footbox closure, allowing for easy ventilation of the feet on warmer nights.
We were impressed with how light and packable this sleeping bag was, given its warmth. It is stuffed with 14.7 ounces of 950-plus fill down and weighs only 25.8 ounces in a regular size on our scale.
We found this sleeping bag warmest and most comfortable when we kept the zipper underneath the body. In this orientation, we could unzip the bag to just below the hip, effectively using it as a quilt, a setup that we found comfortable and warm between about 27 and 45 degrees Fahrenheit.
Below about 25F, we recommend zipping up the sleeping bag all the way but keeping the zipper under the body. Even though most bags have a draft tube, zippers tend to be a cold spot. This zipper’s low profile makes it virtually imperceptible when lying on it.
When fully zipped, the shape is mummy-like for thermal efficiency, snugging around the legs. By contrast, the Enlightened Equipment Convert Sleeping Quilt – 20 Degree, reviewed below, is more egg-shaped, which could be why it wasn’t as warm.
Our only gripe with this sleeping bag was the cord locks around the neck, a literally and figuratively small issue. The neck cinch features two shock cord drawstrings — one on each side — that are adjusted by cinching a small cord lock. Unfortunately, these cord locks cannot hold the neck opening closed, and even small movements uncinch the opening. To remediate this issue, we added an additional cord lock to each shock cord.
The Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree has truly outstanding versatility, making it our recommendation for anyone wanting only one sleeping bag. It’s cozy well into the teens, super-light for its warmth, vents easily, and can be draped blanket-style for warmer nights.
We tested the 20F version, but you can get this sleeping bag in 20-, 30-, and 40-degree Fahrenheit options for fastpacking in any season.
Be sure to read our in-depth Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree review, too!
Type: Hoodless Sleeping Bag/Quilt | Actual Weight: 25.8 ounces (731 grams) in size regular | Fill Weight: 14.7 ounces (417 grams) of 950-plus fill | Temperature Rating: 20F | Packed Size: 7 x 13 inches (17.8 x 33 centimeters), 8 liters
Shop the Feathered Friends Flicker UL Quilt Sleeping Bag - 20 DegreeBest Ultralight Sleeping Bag Without a Hood — Runner-Up: Zpacks Classic Sleeping Bag ($490)
Pros:
- Very light
- Durable #5 coil zipper
Cons:
- Expensive
- 7-denier shell material is less downproof than others we tested
The Zpacks Classic Sleeping Bag is a high-end quilt and sleeping bag hybrid with which we have only minor quibbles, most of which are superseded by the fact that it’s so dang light. This bag comes in three different temperature ratings, and each one is available in seven different size options, with varying lengths and widths. We tested the standard-medium 20-degree Fahrenheit bag.
Weighing only 21.4 ounces at the size we tested, this is the lightest 20F bag on our list. Its premium materials include 13.7 ounces of 900-fill Muscovy Duck down, 7-denier liner, and shell fabrics. The fabrics are thin and light, allowing the down to loft fully. The shell is so thin that it’s scary, but it’s constructed with a tiny ripstop thread woven throughout, providing some peace of mind. Unfortunately, this material has proven to be the least downproof of any bag we tested, with little feathers leaking through here and there. On the plus side, thin fabrics are often super soft against the skin, and this one is no exception.
The bag has a three-quarter-length zipper, allowing you to open it nearly all the way on warm nights and zip it closed during the chillier times of the year. The neck opening cinches closed with a very thin shock cord, stretchy enough not to feel constrictive around the neck. The collar clasp is a plastic wafer clip instead of the snap most companies use, a move we can get behind because it’s secure and easy to use.
So now, you might be wondering what on earth could be wrong with this sleeping bag to make it the runner-up. Honestly, nothing. The Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree, reviewed above, features more high-quality down — 14.7 ounces of 950-plus fill versus 13.7 ounces of 900-fill Muscovy Duck down in this one — and is constructed with a differential cut, and more durable materials. The Zpacks, on the other hand, is $70 cheaper and nearly 4 ounces lighter — and light is the name of the game in fastpacking.
It’s hard to tell why this bag wasn’t quite as warm as the Flicker, but we wondered if the lack of the differential could be the culprit. In short, bags with a differential cut have the shell cut a couple of inches wider than the liner. This difference in material dimensions means that the bag can loft fully even when your elbows, knees, and shoulders press into the liner.
We tested the 20F version, but this bag is available in 30-degree or 10-degree Fahrenheit options as well. Given the chance, we might pick the 30 for summer use and the 10 for fastpacking beyond the shoulder season.
Type: Hoodless Sleeping Bag | Actual Weight: 21.4 ounces (606 grams) in size standard/medium | Fill Weight: 13.7 ounces (388 grams) 900 fill Muscovy Duck down | Temperature Rating: 20F | Packed Size: 6 x 12 inches (15 x 30 centimeters), 7.1 liters
Shop the Zpacks Classic Sleeping BagLightest Ultralight Sleeping Bag: Western Mountaineering HighLite ($445)
- Impressively warm for the weight
- Very light
Cons:
- Temperature rating limits its versatility
Weighing a mere 16.2 ounces in our testers’ 5-foot-6-inch length version, the Western Mountaineering HighLite is an incredibly lightweight bag that feels warmer than its 35-degree Fahrenheit rating suggests. It’s perfect for mountain trips when you’re not planning to spend nights high above treeline, and want to keep your pack as light as possible. It’s also ideal for those spring and fall desert trips when the days are perfect for walking and running, but temperatures drop at night to a point that you don’t want to go with an ultra-ultra-lightweight sleep system.
The warmth-to-weight ratio of this sleeping bag is what has us returning to it, trip after trip. It’s not a viable option for really cold outings, but for the majority of our summer fastpacks, it’s just enough. This sleeping bag has been around for a long time and remains a favorite among the ultralight community.
The shell is made of ExtremeLite fabric and weighs less than an ounce. The 12-denier ripstop fabric is incredibly durable for its weight and is filled with 850-plus fill ethically sourced goose down, which is some of the highest-quality down available.
The baffle system is relatively unique, with the horizontal seams sewn completely through. The vertical seams, which make a quilted pattern, are made with strips of netting. This helps keep the down in place while maximizing the loft and, thus, the warmth of the bag.
The half-length #4 YKK zipper is quite small, but we didn’t have any durability issues with it as long as we were careful. In fact, for how light this bag is, we were impressed that after years of use, we didn’t have any issues with the zipper failing, even after countless trips in the Utah desert. The down continued to loft well and stay in place, and we’ve seen people use this bag for well over a decade before finally deciding to replace it … with the exact same bag.
The HighLite comes in three lengths, and you can choose the side on which you want the zipper.
Type: Hooded Mummy | Actual Weight: 16.2 ounces (460 grams) in 5-foot-6-inch size | Fill Weight: 8 ounces (255 grams) 850+ fill goose down | Temperature Rating: 35F | Packed Size: 6 x 12 inches (15 x 30 centimeters), 5.6 liters
Shop the Western Mountaineering HighLite Sleeping BagLightest Ultralight Sleeping Bag — Runner-Up: Sea to Summit Spark Down Sleeping Bag – 30F ($450)
- Baffle pattern optimizes warmth
- Lightweight
- Good draft collar
Cons:
- Not warm enough for high and exposed mountain conditions
Not all trips require a 20-degree Fahrenheit sleeping bag, and the Sea to Summit Spark Down Sleeping Bag – 30F is a lightweight option perfect for warmer fastpacking outings. With a 30F rating, this bag is adequate for many mountain trips when you’re not planning on spending nights in frigid and exposed places. In fact, we chose it for a 6-day late-summer traverse of Wyoming’s Wind River High Route and ended up too warm on a couple of the nights. We also used this bag for spring and fall desert trips when the days were perfect for travel and night temperatures dipped into the 30s.
Weighing 17.1 ounces (484 grams), this lightweight bag compresses to 2.4 liters, making it small enough to fit into essentially any fastpack. The 9.3 ounces of 850+ fill down provides plenty of warmth for the weight. The down has a PFAS-free hydrophobic treatment to help it maintain its loft even if the feathers become damp. We’ve spent many nights pairing this sleeping bag with a marginally breathable SOL Escape bivy, and we never felt like this bag got soggy.
The 10-denier outer fabric employs a PFAS-free DWR coating, and we found it to be plenty durable as long as we took care of it. The hood and neck area are lined with a draft collar to keep cold air out, and the hood cinches down tightly if you want to burrow as deeply in as possible.
With a combination of horizontal and vertical baffles in different areas, this sleeping bag provides warmth where needed while also saving weight and construction costs. The vertical baffles around the core provide a high level of warmth, while the horizontal baffles around the leg area help save weight and reduce construction costs, keeping the sleeping bag’s price reasonable.
This sleeping bag is available in several different temperature ratings. It also comes in a women’s version with extra insulation in areas, like the hips, where women tend to get colder. The women-specific bag weighs 584 grams, which is nearly 100 grams more than the unisex version. Our female tester tested the unisex version and found it warm enough for her needs. If you know you tend to sleep a little colder, you might consider getting the women-specific bag.
We include this sleeping bag in our Best Ultralight Backpacking Gear guide because of its versatility and lightweight performance.
Type: Hooded Mummy | Actual Weight: 17.1 ounces (484 grams) in size regular | Fill Weight: 9.3 ounces (264 grams) of 850+ fill | Temperature Rating: 30F | Packed Size: 2.4 liters
Shop the Sea to Summit Spark Down - 30F Sleeping BagShop the Sea to Summit Spark Down - 30F Sleeping Bag - Women's
Best Ultralight Quilt: Katabatic Gear Alsek 22F Quilt ($480)
Pros:
- Very light
- Comfortable
- Tapered mummy shape is thermally efficient
- Adjustable shoulder girth
- Small packed size
Cons:
- Fiddling with sleeping pad attachment straps isn’t for everyone
The Katabatic Gear Alsek 22F Quilt is an amazingly light and warm quilt with well-thought-out features. On our scale, it weighs 23.7 ounces in size regular and is packed with 14.1 ounces of 900-fill goose down. It also has the most secure sleeping pad attachment system we’ve seen on any quilt.
One of our testers has been using this quilt for nearly 10 years and can speak to the iterations. An older version of this quilt was only 52 inches wide at the shoulder, and a few years ago, Katabatic Gear widened it to 54 inches to increase comfort and reduce drafts. Narrower quilts are more prone to drafts by default. While this 5-foot-11-inch, 160-pound tester liked but didn’t love the older, narrower version, he now has dozens of nights in the latest version and absolutely adores it.
Due to their shape and size, several sleeping bags on our list suffer from inherent inflexibility, often fitting certain bodies better than others. Because this one has an adjustable girth, we found it to fit a wider range of body types better than any other sleeping bag on this list, from those with very narrow shoulders to those with very broad shoulders. The quilt narrows to 54 inches and widens to an effective width of around 66 inches while still sealing in body heat.
While all zipperless quilts are prone to being drafty, this one reduces the risk with several unique design features. This quilt’s differential cut gives it a permanent tube shape, rather than a folded-over blanket shape, so it always looks ready to hug you.
The elastic-hemmed edges seem biased to snug under the body rather than spill out over the edges of your pad. The pad attachment system utilizes a static cord, so it doesn’t stretch when you toss and turn at night. We had no issues with drafts when using this bag.
We have nothing but good things to say about the updated version of this quilt. It is warm and comfortable across a range of temperatures, is adjustable for climate control, and can fit different body sizes.
Type: Quilt | Actual Weight: 23.7 ounces (671 grams) in size regular | Fill Weight: 14.1 ounces (400 grams) of 900 fill | Temperature Rating: 22F | Packed Size: 6.5 x 11.5 inches (16.5 x 29.2 centimeters), 6.5 liters
Shop the Katabatic Gear Alsek 22F QuiltBest Ultralight Quilt — Runner-Up: Enlightened Equipment Convert Sleeping Quilt – 20 Degree ($415)
- Lower price point
- Warm and comfortable
- Can work as a blanket as well
Cons:
- Egg shape is less thermally efficient
The Enlightened Equipment Convert Sleeping Quilt – 20 Degree is a very comfortable, reasonably priced, and versatile quilt. The stock model features a 10-denier shell and liner. The Regular/Regular size weighs 27.2 ounces and is filled with 17.9 ounces of 850-fill water-repellent goose down. This same quilt is also available in a 950-fill option with temperature ratings ranging from 0F to 50F. We selected the 20F rating and down quality that most closely matched the other quilts on our list.
This is one of only two sleeping bags on this list with a drawstring footbox closure — the Feathered Friends Flicker UL Quilt Sleeping Bag — 20 Degree, reviewed above, being the other. On really warm nights, you can unzip this quilt completely and drape it over your body for a cooler sleeping experience.
The foot cinch doesn’t close as securely as the Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree, and it’s the possible culprit for the cold feet one of our testers experienced during one 20F night in the Wasatch Mountains in early May. Because the fully open bag is more or less rectangular, it transforms into an egg-shaped, rather than mummy-shaped, tube when zipped. This leaves a lot of room around the legs. A few of our testers enjoyed the extra space, but others wished the bag was more mummy-shaped to provide more thermal efficiency.
The sleeping pad attachment straps are stretchy, which we found less effective than the static cord attachments on the Katabatic Gear Alsek 22F Quilt. On the other hand, the wafer clips are easier to use than the little cord lock system on the Katabatic Gear quilt.
The shell and liner materials are concerning, at least in appearance, because they lack ripstop. While they feel thicker than the 7-denier fabrics on the Zpacks Classic Sleeping Bag, and could theoretically be more downproof, they probably won’t withstand dog claws or general abuse as well as a fabric with ripstop. If a tear begins, it will only get bigger over time. Only time will tell if this is a real issue, but our testers preferred the look and feel of some of the fabrics on other bags that got our highest ratings.
Lastly, this quilt doesn’t have a differential cut, but the importance of this factor was a matter of debate between a few of our testers.
Overall, this sleeping bag is a solid choice for those seeking a sleeping bag/quilt hybrid that performs well between 20F and 60F. If you want versatility without spending extra money on the premium features of higher-rated bags, definitely check it out. You can also select the same bag in 50-, 40-, 30-, 10-, or 0-degree Fahrenheit versions.
Type: Hoodless Sleeping Bag/Quilt | Actual Weight: 27.2 ounces (772 grams) in size regular/regular | Fill Weight: 17.9 ounces (507 grams) 850 fill water-repellent down | Temperature Rating: 20F | Packed Size: 6.5 x 12 inches (16.5 x 30.5 centimeters), 8.3 liters
Shop the Enlightened Equipment Convert Sleeping Quilt - 20 DegreeBest Budget Ultralight Quilt: Outdoor Vitals StormLoft Down TopQuilt 15 ($355)
Pros:
- Inexpensive
- Warm
Cons:
- Ineffective sleeping pad attachment straps and flimsy clips
The Outdoor Vitals StormLoft Down TopQuilt 15 made our list primarily because of its reasonable price tag. This quilt is moderately light at 24.5 ounces, constructed from decent materials, including 10-denier shell and liner fabrics, and stuffed with 15 ounces of 800-fill water-repellent duck down. This is an excellent option if you’re just starting fastpacking and want a quilt that provides great value for the cost.
We chose this quilt with a temperature rating of 15 degrees Fahrenheit but were skeptical that this rating was realistic. With 17.1 ounces of water-resistant 800-fill duck down inside, we didn’t expect it could be as warm as other bags with higher-quality down, and our testing proved our suspicions correct. But in the end, that’s all right with us, though, as this quilt has an incredible price tag!
This quilt’s legs and footbox appear loftier than the torso area, which isn’t necessarily bad because it’s easier to add an extra layer to your upper body than to your legs if you need extra warmth. One of our testers got chilly in the high desert when temperatures plunged unexpectedly to the high 30s after a storm passed, but she warmed up after putting on her down jacket. Other testers found the quilt plenty warm to about 35F while wearing only base layers and a warm hat.
The quilt’s stretchy pad attachment straps don’t slide easily through the wafer clips, making them nearly impossible to adjust. One of our testers broke a clip while adjusting the straps, making the quilt more susceptible to drafts during one cold night in Colorado’s San Juan Mountains. Fortunately, she simply tucked the edge under her body and slept all night comfortably.
That said, don’t think twice about the shortcomings of this quilt if you can’t spend a ton of money on a premium quilt — it’s good enough for most situations. And sometimes — dare we say usually — good enough is all anyone ever needs. Given that the price of entry into fastpacking gear can be steep, we highly recommend this quilt to those who are putting together their first kit.
Type: Quilt | Actual Weight: 24.5 ounces (695 grams) in size regular with pad attachment straps | Fill Weight: 17.1 ounces (485 grams) of 800-fill water-repellent down | Temperature Rating: 15F | Packed Size: 7 x 12 inches (17.8 x 30.5 centimeters), 9.6 liters
Shop the Outdoor Vitals StormLoft Down TopQuilt 15Comparing the Best Ultralight Sleeping Bags
| SLEEPING BAG | PRICE | WEIGHT | TEMP RATING | PACKED SIZE |
| Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree | $660 | 27.0 ounces | 20F | 7 x 12.5 inches |
| Montbell Seamless Down Hugger 800 #2 | $455 | 22.7 ounces | 25F | 5.9 x 11.8 inches |
| Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree | $560 | 25.8 ounces | 20F | 7 x 13 inches |
| Zpacks Classic Sleeping Bag | $490 | 21.4 ounces | 20F | 6 x 12 inches |
| Western Mountaineering HighLite | $445 | 16.2 ounces | 35F | 6 x 12 inches |
| Sea to Summit Spark Down Sleeping Bag – 30F | $450 | 17.1 ounces | 30F | 2.4 liters |
| Katabatic Gear Alsek 22F Quilt | $480 | 23.7 ounces | 22F | 6.5 x 11.5 inches |
| Enlightened Equipment Convert Sleeping Quilt – 20 Degree | $415 | 27.2 ounces | 20F | 6.5 x 12 inches |
| Outdoor Vitals StormLoft Down TopQuilt 15 | $355 | 24.5 ounces | 15F | 7 x 12 inches |
Buyer’s Guide: How to Choose an Ultralight Sleeping Bag or Quilt
Types of Sleeping Bags
There are three primary types of ultralight sleeping bags, with some variation and crossover between the categories. For this guide to the best ultralight sleeping bags, we’ve reviewed hoodless sleeping bags, like the Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree, hooded sleeping bags, such as the Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree, and quilts, including the Katabatic Gear Alsek 22F Quilt.
The best option for you will be based on your sleeping style, how you plan to use the rest of your gear in conjunction with your sleep system, and the types of trips you want to take. We hesitate to say there is a best ultralight sleeping bag for back sleepers and one for side sleepers. Instead, we’ll explain how each style should work.

iRunFar’s Meghan Hicks opted for the Western Mountaineering HighLite on a trip across the Wind Rivers High Route in Wyoming. Photo: iRunFar/Eszter Horanyi
Hooded or Mummy Sleeping Bags
In general, hooded bags like the Montbell Seamless Down Hugger 800 #2, Western Mountaineering HighLite, and Sea to Summit Spark Down Sleeping Bag – 30F should move with you as you toss and turn because your head remains in the hood. Regarding warmth, the primary benefit of hooded bags is that they provide insulation for your head, eliminating the need to wear a beanie or hooded jacket inside.
The issue is that if you want to use your hooded jacket or beanie as part of your sleep system to save weight, you will face some redundancy issues. Some of our testers also like that hooded bags keep their pillow right where they want it, and other testers like the ability to cinch the hood down around their face for added warmth.
Hoodless Sleeping Bags
Hoodless sleeping bags can either move with you or stay stationary because there is no fixed hood. These bags shine in part because they work well with whatever layers you may want to bring along.
If you plan to pack a hooded jacket on every trip, you can wear it inside your Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree, effectively tacking a hood onto it. Fastpacking necessitates the implementation of multiple-use items for efficiency and weight savings, which is why many of us here at iRunFar like hoodless bags.
Some of our testers — especially those who tend to sleep cold, or try to get away with too light a sleeping bag for the conditions — feel like having a hood that they can cinch down over everything but their nose and mouth adds enough extra warmth to justify the weight of a hood.
Quilt-Style Sleeping Bags
Quilts such as the Katabatic Gear Alsek 22F Quilt and Outdoor Vitals StormLoft Down TopQuilt 15 remain fixed to a sleeping pad, with your body spinning rotisserie-style inside the pad and quilt sandwich. Like hoodless sleeping bags, quilts also work with hooded jackets to reduce gear redundancy.
Quilts have three real benefits. First, they keep weight low by making a sleeping bag “bottomless,” effectively leaving out fabric and down that would normally wrap underneath the body. Since the down under your body compresses in a normal sleeping bag, and thus doesn’t insulate very well, there’s little actual effective insulation lost with this system. Second, quilts can potentially increase comfort by making the width of the bag adjustable. Third, they ensure that the top of the bag — the area where condensation and frost will land — never ends up underneath the body, where the moisture could get pushed through the fabric into the down.
The main downside of a quilt is its susceptibility to drafts. Futzing with straps and cords can also be annoying, especially after a long day when all you want to do is sleep.

iRunFar’s Meghan Hicks and Eszter Horanyi took a pair of Montbell Seamless Down Hugger 800 #2 on a late fall desert trip on the Colorado Plateau. Photo: iRunFar/Eszter Horanyi
Weight
For this guide, we capped the upper weight of sleeping bags at 29 ounces because fastpacking requires lightweight sleeping bags. In general, lighter sleeping bags compress small enough to fit in a 25-liter pack, making running more enjoyable. The lightest bag on our list is the Western Mountaineering HighLite, which weighs 16.2 ounces. However, the best ultralight sleeping bag must also be warm enough for the conditions, and finding the right balance between weight and warmth is always the ultimate challenge.
The Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree, our favorite overall hooded sleeping bag, is also the heaviest on the list. At 27 ounces, it’s just light enough to be part of a cold-weather fastpacking kit, as long as you streamline the rest of your gear. If you’re only going to own one sleeping bag, we recommend investing in one at the lower end of the temperature range that you’re going to camp in, even if it’s a bit heavier.
To learn more about fastpacks that can easily carry any of the sleeping bags included in this guide, you can check out our Best Fastpacking Packs guide. To learn more about weight considerations in an entire fastpacking kit, you can check out our Best Ultralight Backpacking Gear guide.
Warmth
The best fastpacking bags must have excellent warmth-to-weight ratios, or we won’t be stuffing them in our packs. One way to determine this is to identify how much of a bag’s total weight is down. To create this guide, we chose sleeping bags with weights made up of primarily down, from 50% to 65%. This ensured that any 20F bag we chose would theoretically be warm at or below about 25 degrees Fahrenheit on an insulated sleeping pad. After a while, we sought out some 30F and 35F bags with amazing warmth-to-weight ratios as well. So, before even considering the cost or features, we compiled a list of theoretically lightweight and warm sleeping bags.
That left us mostly with pretty expensive bags, such as the insanely warm Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree. Sleeping bags with great warmth-to-weight ratios, by default, use the highest-quality down, which is one reason they are more costly than heavier bags. Exceptions to this rule are the budget options we found, such as the Outdoor Vitals StormLoft Down TopQuilt 15. This quilt utilizes mid-grade down and ultralight shell materials with minimal features and the simplest design. It’s pretty warm for what it is.
We also tested a handful of warmer-weather bags, like the 35F Western Mountaineering HighLite and the 30F Sea to Summit Spark Down Sleeping Bag – 30F, for situations where you don’t need a 20F bag to stay warm and want to save some weight in your pack.

Hallie Taylor tests a Sea To Summit Women’s Spark 15 Sleeping Bag and a Feathered Friends Swallow UL 20/30 Sleeping Bag – 20-degree under a purple tarp on a rainy night in the Wasatch Mountains of northern Utah. Photo: iRunFar/Ben Kilbourne
Insulation Material
The two primary insulation materials in sleeping bags are down and synthetic. Down comes from either ducks or geese. Synthetic insulation, such as Climashield Apex, is continuous filament insulation, meaning it is manufactured in large sheets and requires no quilting for construction.
People choose synthetic-fill sleeping bags for exceptionally wet climates because they keep you warm even when damp. Some brands, such as Enlightened Equipment, offer synthetic versions of some of their quilts.
A greater amount of synthetic insulation is generally required to achieve the same warmth as a high-grade down fill, so we didn’t test any synthetic sleeping bags. Synthetic insulation also doesn’t pack down quite as small as down and doesn’t spring back from compression as well, meaning it has a shorter lifespan. We recommend down sleeping bags, including our favorite, the Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree, over synthetic ones for nearly any fastpacking situation in drier climates.
Down Fill Power or Loft
Fill power measures the “poofiness” or “floofiness” — depending on which iRunFar tester you talk to — or lofting ability of goose or duck down, which are the primary insulation materials in sleeping bags. Lofting is the capability of down clusters to trap air. The higher the grade of down, the loftier it will be, and the more air — and thus body heat — it will trap.
Fill power is measured by placing 30 grams — or about 1 ounce — of down in a plexiglass cylinder and then compressed. Higher grades of down continue to fill higher volumes than lower grades.
To use a real-world example, a sleeping bag with 15 ounces of 800-fill down will be less lofty and, therefore, less warm than one with 15 ounces of 950-plus-fill down. To reach the same loft and warmth as the 950-plus-fill sleeping bag, the one with 800-fill would need several more ounces of down, making it heavier.
The only downside to high-loft down is its high price tag. The Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree has 16.8 ounces of 950-plus-fill down and is the highest-priced bag on our list, at $660.
When shopping for a sleeping bag, we recommend looking for one with as high of a loft rating as your budget allows. This will ensure a warmer sleeping experience at a lower weight.

Ben Kilbourne has been using the Katabatic Gear Alsek 22F Quilt more than any other bag for nearly 10 years, a true testament to its performance and versatility. iRunFar/Ben Kilbourne
Responsible Down Standard (RDS) Certification
Textile Exchange states, “The Responsible Down Standard (RDS) aims to ensure that down and feathers come from animals that have not been subjected to any unnecessary harm.” Every sleeping bag on this list uses RDS-certified down, and we wouldn’t have chosen any of them if they didn’t. The Katabatic Gear Alsek 22F Quilt comes with both goose-down and duck-down options.
Versatility
Versatility in fastpacking gear enables you to use a single item for multiple purposes. The Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree is probably the most versatile bag on this list because it is light and warm and can open at the foot and work as a blanket in warmer weather.
This can be nice if you only want to own one bag and know your trips will take you through mountains and deserts in all seasons. That said, it’s overkill for some situations where a lighter bag, like the Western Mountaineering HighLite, will keep you plenty warm and save you a significant amount of weight in your pack.
Hooded mummy bags like the Sea to Summit Spark Down Sleeping Bag – 30F can be less versatile than hoodless zippered bags or quilts because they have fewer venting options. Also, if you’re carrying a jacket with a hood or a warm hat, you may not need a hood on your sleeping bag.

Testing a sleeping bag on a decidedly not-ultralight hiking and packrafting trip in Utah. Photo: iRunFar/Eszter Horanyi
Durability
Many of this guide’s best ultralight sleeping bags utilize ultralight shell materials that sometimes appear scarily thin. The 7-denier shell on the Zpacks Classic Sleeping Bag is an example of a shell material that feels like it needs to be treated carefully. That said, not all shell materials are created equal, and it’s possible that the Zpacks’ 7-denier shell could outlast 10-denier or 15-denier materials on some cheaper bags.
We have seen 7-denier material withstand dog paws traveling across them without damage, while the same paws went through the 10-denier material of a different bag like butter. The latter bag’s main issue was a lack of ripstop within the fabric. Ripstop is a woven fabric with a grid of stronger reinforcement fibers to make it more resistant to ripping.
We recommend choosing a sleeping bag fabric with a ripstop whenever possible, no matter the denier. The Enlightened Equipment Convert Sleeping Quilt – 20 Degree lacks ripstop in its material, which raises concerns about its durability.
Sleeping bag durability includes both the shell material and the quality of the down. Higher grades of down, such as the 950-plus fill found on the Feathered Friends sleeping bags, will generally continue lofting longer than the 800 fill found on the Outdoor Vitals StormLoft Down TopQuilt 15. It’s essential to store your sleeping bag uncompressed and as lofted as possible to preserve the down and prevent premature clumping.
Zippers are another point of failure on a sleeping bag, as sand can work its way into the coil and either jam or wear down the sliders. Generally, a larger coil will last longer than a smaller one. We recommend sleeping bags with #5 coil zippers, such as the Zpacks Classic Sleeping Bag, over bags with #3 zippers, like the Enlightened Equipment Convert Sleeping Quilt – 20 Degree, for the sake of durability.

Hallie Taylor tests a sleeping bag’s warmth while eating breakfast on a cool morning in Colorado. Photo: iRunFar/Eszter Horanyi
Packed Size
Every sleeping bag on this list features an ultralight shell, liner materials, and high-quality down for excellent packability. The smallest-packing sleeping bag on our list is the Western Mountaineering HighLite, measuring 6 x 12 inches when packed. This bag takes up very little space, fitting easily inside even a tiny fastpacking pack such as the Pa’lante Packs Joey. You can check out more fastpack options in our Best Fastpacking Packs guide.
A sleeping bag is likely the largest volume item in a fastpack, so you’ll want to consider it carefully when assembling a fastpacking kit. If you want to fit everything into a 25-liter pack, you’ll need a more packable sleeping bag than if you’re using a 30-liter or larger pack.
Why You Should Trust Us
The iRunFar team has been fastpacking for over a decade and has watched this adventure niche grow. What started as two separate endeavors — ultralight backpacking and adventure running — have now merged into one: fastpacking.
For many of us, a good night’s rest is critical for completing the next day’s miles. We frequently have no idea where we’ll end up for the night — parked on the edge of a snowfield at 13,000 feet or cowboy camping below the cold, cloudless firmament — so we want to haul along a sleeping bag that will perform wherever we lie down.
While a couple of fastpacking-appropriate sleeping bags have been in the iRunFar team’s rotation for a few years, for this guide, we set out to research dozens and test 15 of what we thought could be the best sleeping bags for three-season fastpacking and ultralight backpacking.
We rated the bags on their warmth, shape, comfort, and weight, carefully examining the quality and quantity of down in each. Since the initial publication of this guide, we have continued to add new sleeping bags to our rotation in order to providing you with recommendations on the best ultralight sleeping bag options on the market.
We tested sleeping bags on adventures in the San Juan Mountains of southwestern Colorado; the Wasatch Mountains of northern Utah; the Mazatzal Mountains of central Arizona; and various locations throughout the canyon country of the Colorado Plateau. Some of our team members also head to New Zealand regularly to test gear in a completely different climate. Our team has a wide range of body types, and we tested these ultralight sleeping bags in various temperatures and environmental conditions.

Testing the Enlightened Equipment Convert Sleeping Quilt – 20 Degree in Colorado, which we called our runner-up for the best fastpacking sleeping bag. Photo: iRunFar/Eszter Horanyi
Frequently Asked Questions About Ultralight Sleeping Bags and Quilts
What fill power is best for a fastpacking sleeping bag?
This is one of the very few areas where there’s a pretty simple answer that doesn’t require much nuance. Higher fill-power sleeping bags, like the 950-fill Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree, are lighter, warmer for their weight, and will last longer than lower fill-power sleeping bags. The only downside is the higher cost.
A good sleeping bag filled with quality down will easily last 20 years if you take care of it. The Feathered Friends sleeping bags utilize the highest-grade down of any on our list. The Outdoor Vitals StormLoft Down TopQuilt 15 uses 800-fill down, but is also the least expensive sleeping bag in this guide.
How should my sleeping bag or quilt fit?
Fit is somewhat subjective, so we won’t give you any absolutes here. When shopping for a fastpacking sleeping bag, remember that narrower bags are generally more thermally efficient, meaning they’ll be warmer for their weight than wider sleeping bags. Wider sleeping bags create a lot of air space between your body and the bag, sometimes making it difficult to warm up.
Mummy bags like the Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree and Western Mountaineering HighLite will be more thermally efficient than the egg-shaped Enlightened Equipment Convert Sleeping Quilt – 20 Degree.
If you can’t stand narrowness and prefer wider bags for comfort, consider quilts, as their shoulder circumference is adjustable. You can widen the shoulder girth of the Katabatic Gear Alsek 22F Quilt to around 66 inches and narrow it to 54 inches. Additionally, you can buy most sleeping bags on this list in different widths and lengths.

iRunFar’s Meghan Hicks and Eszter Horanyi test the Montbell Seamless Down Hugger 800 #2 sleeping bags on a fall desert trip. Photo: iRunFar/Eszter Horanyi
Do I need water-resistant down?
Some of the sleeping bags on our list, including the Outdoor Vitals StormLoft Down TopQuilt 15 and the Sea to Summit Spark Down Sleeping Bag – 30F, have hydrophobic or water-repellent down. This means the down clusters are treated with a durable water-repellent (DWR) chemical coating. Third-party tests show that this treatment indeed increases the down’s water resistance. However, it is unclear how long this treatment will last or if it affects the down’s long-term lofting ability.
Some major brands, such as Western Mountaineering and Feathered Friends, don’t use treated down. However, if you want extra peace of mind during fastpacking adventures in a wet climate, choosing a bag with hydrophobic down probably couldn’t hurt. Sometimes, especially if you’re sleeping in a bivy or a single-wall tent, it’s nearly impossible to wake up with a completely dry sleeping bag. In this case, it’s often a good idea to dry a down sleeping bag out during a lunch stop to ensure the down can stay as dry as possible throughout a longer trip.
If you consistently fastpack in wet or humid climates, you might want to consider a synthetic sleeping bag. Synthetic fill will remain warm even if wet, while down will lose its insulating properties as it gets damp and the down feathers start to clump together. Synthetic insulation has a lower warmth-to-weight ratio compared to down, so you’ll need to carry a heavier bag to achieve the same level of warmth.
These sleeping bags are expensive! Do I really need to spend $400 or more on a sleeping bag?
The four most expensive items in a fastpacking kit are the fastpack, sleeping pad, tent, and sleeping bag. However, excellent budget options are available in every category except sleeping bags. You can find $150 packs, $50 pads, and $100 tarps, but sleeping bags are different. The least expensive bag on our list, the Outdoor Vitals StormLoft Down TopQuilt 15, is still $355!
However, because a high-quality sleeping bag can last 20 years, we recommend saving for a good one. With this in mind, we stand by our top pick, the Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree. At $560, it’s undoubtedly expensive, but if you take care of it, it will continue to perform well in virtually any fastpacking scenario for a long time.
If a $500 sleeping bag makes it 20 years, that’s only $25 a year.

An ultralight sleeping bag will fit into a 30-liter fastpacking pack, allowing you to cover many miles. Photo: iRunFar/Eszter Horanyi
What’s the best fastpacking sleeping pad to pair with my quilt or sleeping bag?
Many folks, including some of our testers, sleep on a foam or inflatable torso-length pad, placing their pack under their legs for a bit of additional warmth. This is a great way to save weight by incorporating every possible item into your sleep system. It’s also pretty hardcore. If you can get a good night’s rest in this Spartan fashion, by all means, go for it. But to stay warm using this system, you may want to bring along a quilt or sleeping bag that’s a bit warmer than the expected lows because the insulation value of the assorted items under your legs will be much lower than the insulation value of a real sleeping pad. Any of the sleeping bags and quilts listed here will work for this method.
If you want to ensure that you get some solid deep sleep and REM cycles so you can crush another 30 miles the next day, there’s absolutely no shame in carrying a full-length inflatable sleeping pad. And if you’re a quilt user, it’s much easier to attach your quilt to a full-length pad. We found the Enlightened Equipment Convert Sleeping Quilt – 20 Degree to be a bit more difficult to attach to a pad than the Katabatic Gear Alsek 22F Quilt. Pads have gotten so good over the last decade or so that most of the fastpackers on our team now carry full-length ultralight pads. Check out our Therm-a-Rest Neo Air XLite NXT Sleeping Pad review — at only 13 ounces in a size regular, it has become a team favorite. For more packable, light, comfy, and fastpacking-worthy sleeping pads, check out our Best Ultralight Sleeping Pads guide.
Should I get a down or synthetic sleeping bag?
High-quality down sleeping bags are warmer for the weight than similarly rated synthetic sleeping bags, prompting us to choose them for most fastpacking trips. Down insulation also compresses smaller than synthetic insulation and bounces back from compression better than synthetic, giving it a longer lifespan. The primary benefit of synthetic sleeping bags is that they retain their warmth even when wet.
Some sleeping bags, such as the Outdoor Vitals StormLoft Down TopQuilt 15 and Sea to Summit Spark Down Sleeping Bag – 30F, have down treated with a water-repellent coating that helps keep them warmer when damp. People who try to avoid using animal products may also prefer to opt for a synthetic sleeping bag.

This guide features award-winning sleeping bags, including the Katabatic Gear Alsek 22F Quilt on the left and the Outdoor Vitals StormLoft Down TopQuilt 15. Photo: iRunFar/Ben Kilbourne
What is the difference between a sleeping bag and a quilt? Which one should I get?
The main difference is that sleeping bags fully encapsulate you, whereas quilts are open underneath your body. Choose a sleeping bag like the Western Mountaineering HighLite if you want it to move with you when you toss and turn. Choose a quilt like the Katabatic Gear Alsek 22F Quilt if you want it to remain fixed to your sleeping pad as your body spins inside of it.
Quilts save weight by losing the zipper and the material that would normally be underneath the body. They are also adjustable in width, widening for comfort and snugging close for thermal efficiency. This adjustability also means that a single quilt could fit a range of body shapes and sizes.
One downside of quilts is that they can be susceptible to drafts. The cordage or webbing used to attach them to your sleeping pad can be a pain to fiddle with, especially when you’re tired and cold. The clips on the Outdoor Vitals StormLoft Down TopQuilt 15 had durability issues, but we could tuck the quilt underneath us and stay warm.
We recommend sleeping bags for those who don’t want to spend a lot of time setting up their sleep system. You just get in it and pass out. Quilts have a bit of a learning curve.
I sleep cold at night. Which sleeping bag should I get?
Instead of looking at temperature ratings, note the amount of down in each sleeping bag you’re trying to choose between. For example, the Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree features 16.8 ounces of 950-plus fill and is rated at 20F. The Outdoor Vitals StormLoft Down TopQuilt 15 has a lower claimed rating — 15F — and a similar weight but lower grade of down. In this case, the Swallow will be a far warmer bag than the StormLoft, even if the marketing claims otherwise. Our testing proved this, with all testers agreeing that the Swallow was the warmest bag we tried.
Most sleeping bags come with three different temperature ratings: Comfort, Lower Limit, and Extreme. Companies generally define the comfort temperature as the rating where a “standard” woman can sleep comfortably through the night. We fully acknowledge the shortcomings of this rating system, as different women sleep comfortably at different temperatures, and some sleep as warm or even warmer than men.
However, this is the system that has been established. Since women, on average, tend to sleep colder than men for various physiological reasons, this rating is higher than the Lower Limit, which is where a “standard” man can sleep comfortably for eight hours. The extreme rating is defined as the temperature at which a “standard” woman will be able to survive for six hours without the risk of death from hypothermia, but you’ll be shivering for sure.
When choosing a sleeping bag, determine whether you’re a warm or cold sleeper and select one based on how important complete warmth is to you versus saving a bit of weight.

Hallie Taylor tests a Sea to Summit sleeping bag in Utah’s Wasatch Mountains. Photo: iRunFar/Ben Kilbourne
If I sleep hot at night, which sleeping bag should I get? Should I get a quilt?
Most sleeping bags on our list come in different temperature ratings. Our top hoodless pick, the Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree, is also available in 30- and 40-degree Fahrenheit ratings for those who sleep hot.
If you sleep hot at night, we recommend getting a sleeping bag or quilt with a full-length zipper and a drawstring footbox, such as the Enlightened Equipment Convert Sleeping Quilt – 20 Degree. These bags provide more venting options than any others on our list. If you get too hot, you can uncinch the drawstring, poke your feet out, or unzip the entire thing and drape it over you like a blanket.
Some quilts are better for hot sleepers than others. The Katabatic Gear Alsek 22F Quilt doesn’t vent as well as others because it doesn’t unzip all the way or open at the feet.
Can I push a 40- or 30-degree Fahrenheit sleeping bag into colder temperatures?
There are several steps you can take to make a lighter sleeping bag work in temperatures lower than what it was designed for. Many fastpackers wear most or all of their layers inside their sleeping bag to effectively boost its rating while also making sure there’s no warmth redundancy in their kit. By wearing pants, socks, a baselayer, and a puffy, you may be able to push a 40F or 30F sleeping bag beyond its claimed rating — as long as your layers are dry. We’ve taken the 35F Western Mountaineering HighLite sleeping bag into temperatures far below its rating and stayed warm by wearing all of our clothes.
The body does a better job of keeping us warm when we’re hydrated, so drink plenty of water and maybe even some electrolytes while in camp. One of our testers swears by a hot electrolyte drink mix before bed.
One of the best ways to sleep warm on fastpacking trips is to select warm campsites. Select sites that are sheltered from the wind and are away from marshy areas or depressions where cold air settles at night. While camping right next to a river or lake can be aesthetic, these areas tend to also be the coldest. Getting just a handful of feet above a body of water can make a big difference in air temperature.
Using a shelter can also let you get away with a lighter sleeping bag. Choosing a four-sided, fully enclosed shelter will block wind and trap ambient warm air heated by your body. For some of our favorite fastpacking shelters, check out our Best Ultralight Tents guide
Want to really make sure you stay warm? Combine all of the above!
How should I take care of my sleeping bag? How do I wash my sleeping bag?
You can take several steps to extend the life expectancy and functionality of your sleeping bag.
- Sleep in base layers or a sleeping bag liner to prevent skin oils from soaking into the sleeping bag and degrading the down.
- Don’t compress your sleeping bag longer than necessary. Too much compression can reduce the lofting ability of down.
- Store your sleeping bag hanging or in a large, breathable storage bag, allowing it to loft as much as possible. If you plan to hang your sleeping bag, do so in a closet with a closed door. As one of our testers tragically discovered, cats love to climb sleeping bags.
- Wash your sleeping bag by hand or in a front-loading washer on a gentle cycle. Use soap made for washing down-filled items, such as Nikwax Down Wash Direct and rinse at least twice to ensure all the soap is removed. Set the drier to low and tumble it with three tennis balls to break up clumping down clusters.
With proper care, a high-end sleeping bag like the Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree can last a very long time. Investing in the best ultralight sleeping bag your budget allows for and taking care of it can make it worth the price.

Some of our current and past sleeping bags from left to right are the Feathered Friends Flicker UL Quilt Sleeping Bag – 20 Degree, Feathered Friends Swallow UL 20/30 Sleeping Bag – 20 Degree, Katabatic Gear Alsek 22F Quilt, Feathered Friends Tanager 20 CFL Sleeping Bag, REI Co-op Magma 15 Sleeping Bag – Men’s, Outdoor Vitals StormLoft Down TopQuilt 15, Zpacks Classic Sleeping Bag, and Enlightened Equipment Convert Sleeping Quilt – 20 Degree. Photo: iRunFar/Ben Kilbourne
I ripped a hole in my sleeping bag. What do I do?
We recommend carrying stick-on patches on your fastpacking trips to field repair sleeping bag holes. A single sheet of Tear Aid Type A should be plenty. First, cut the patch to cover the tear completely and round the corners so it won’t peel. Then, clean any dirt away from the tear with water or alcohol and let it dry completely. Peel the backing from the patch and press it firmly over the tear.
A Tear Aid patch may last for a long time, but it probably won’t withstand multiple laundry cycles. If the tear is large, contact the manufacturer to see if they will sew a more permanent patch over it.
A sleeping bag like the Outdoor Vitals StormLoft Down TopQuilt 15, with its 10-denier liner and shell, will be more resistant to tears and scuffs than some extremely ultralight bags. Thinner fabrics with ripstop, such as those on the Zpacks Classic Sleeping Bag and Western Mountaineering HighLite, can be both incredibly thin and durable.
Call for Comments
- Do you prefer sleeping bags or quilts? Hooded or hoodless bags?
- How low have you pushed a 20F sleeping bag?
- What’s your favorite layering system for sleeping?









