The Nemo Disco Endless Promise 15 ($300) is a comfortable, feature-rich sleeping bag that prioritizes roominess and temperature control. Its hourglass shape, excellent ventilation, and thoughtful details make it one of the most luxe-feeling backpacking bags we’ve used, especially if you’re a side sleeper. It’s heavy and bulky compared to many competitors, but if sleeping well matters more to you than achieving the lowest pack weight, the Disco is an easy bag to like.
Warmth / Weight
Comfort
Features
Durability
Water Resistance
Sustainability
Temp Rating
27/16°F (ISO Comfort/Limit)
Weight
2 lb. 14 oz.
Fill
1 lb. 7 oz. of 650-fill down
Shell
20D polyester
Shoulder/Hip Girth
62/57 in.
Packed Volume
14.9L
Other Temps
30F
Pros
Cons
Nemo Disco 15
For this season's top models, see our guide to the Best Backpacking Sleeping Bags.
At nearly 3 pounds, the Nemo Disco Endless Promise 15 is one of the heavier backpacking sleeping bags that Better Trail has tested in this temperature range. Its weight and bulk all but rule it out for fast-and-light trips, especially when you compare it to premium 15-degree bags like the Sea to Summit Spark (1 lb. 9.7 oz.) or Western Mountaineering Ultralight (1 lb. 13 oz.), which are far lighter—but, at more than $500, also far more expensive.
To break down the differences: Those models are stuffed with 850-fill down, but the Disco’s insulation is 650-fill, which is considerably less lofty. Lower fill power down is cheaper, but it also means that more of it is required to hit the sleeping bag’s ISO rating. To this end, the Disco 15 contains a whopping 1 pound 7 ounces of insulation, which helps explain its weight. That also means that the Disco is far larger when packed than the Spark and the Ultralight, so if you’re a minimalist hiker, this is not the sleeping bag for you. All in all, the Disco’s warmth-to-weight ratio is its biggest compromise, which Nemo makes in the name of comfort.
Weight aside, it is a genuinely warm bag. I tested the Nemo Disco 15 in an alpine hut next to a lake with high humidity, where overnight temperatures dipped into the low 30s, and I stayed warm the entire night while sleeping on a basic hut mat. Its oversized draft collar (which you can fold out of the bag or snuggle into like a blanket), draft tube, cinchable hood, and zippered chest make it easy to fine-tune warmth. I could vent without fully unzipping the bag, which helped prevent overheating while still sealing out drafts. It’s not a light bag, but it’s versatile across a wide range of temperatures.
Comfort is where the Nemo Disco 15 truly shines. The bag’s hourglass shape provides significant room at the shoulders (62-in. girth) and knees (61 in.) while narrowing at the hips (57 in.). This design is meant to reduce dead air that can make you cold while still granting plenty of space, and it works exactly as intended. As someone who switches sides frequently while sleeping, I immediately appreciated how unrestricted the bag felt. It offers far more freedom of movement than a traditional mummy shape without sacrificing too much warmth.
The spacious footbox keeps my feet from feeling cramped, and the silhouette feels more like a semi-rectangular bag (which you probably wouldn’t use for backpacking at all) than a mummy. Compared to other comfort-oriented backpacking sleeping bags I’ve used, including slimmer, side-sleeper-specific bags, the Disco strikes a much better balance between space and insulation efficiency.
The fabric on the Disco isn’t the softest I’ve encountered, and if you’re particularly sensitive to texture, a silk or cotton liner would add a noticeable boost in comfort. In terms of noise levels, they were typical for a down bag and nothing distracting. I also liked the baffle layout—vertical on the upper body and horizontal on the lower—which seemed to help the bag drape naturally as I shifted positions. Between the roomy cut, the cozy draft collar, and the customizable venting system, the Disco feels built for folks who want to thrive, not just survive, in the backcountry.
For a backpacking sleeping bag, the Nemo Disco 15 is unusually feature-rich, and it’s clear Nemo prioritized usability over minimalism. The standout feature is the Thermo Gill system, which is comprised of two zippered vents near the torso with both internal and external zippers. When opened, they expose a jersey mesh that releases heat without letting cold drafts rush in. I haven’t used another bag with this kind of ventilation, and it genuinely works.
The oversized “Blanket Fold” draft collar is another highlight. I could flip it outward on warmer nights to encourage airflow or tuck it in tightly when temperatures dropped. The hood is fully cinchable and paired with a full-length draft tube along the zipper to seal in warmth.
There’s also a small pillow barn in the hood designed to hold a backpacking pillow or extra clothes. It’s a tight fit—you’ll want to insert your pillow before inflating—but once set up, it kept everything in place. Last but not least, Nemo includes a proper compression sack with four straps, which lets you shrink the bag down to roughly the size of a small volleyball. It’s heavier than a basic stuff sack, but it matches the bag’s comfort-first philosophy.
The Disco feels notably more durable than most down backpacking sleeping bags I’ve used. It’s made with a 20-denier recycled ripstop polyester shell with a durable water-repellent (DWR) finish, and is thicker than the fabrics found on many premium ultralight 15-degree bags. I never felt like I needed to baby it.
The reinforced hood and footbox stood out as well. They’re built with an extra layer of fabric that’s also covered with a waterproof coating. The bag’s head and foot are what move around the most and can potentially snag most frequently, and they also come into contact with tent walls wet from condensation; the reinforcement helps keep those areas rip-free and dry. Finally, the Disco’s anti-snag zippers worked fine—nothing remarkable, but no issues during testing.
All in all, the Nemo Disco inspires more confidence than most other backpacking bags I’ve used. While it’s heavier than I’d prefer, the added durability makes the weight feel more justified, especially for weekend trips where comfort and longevity matter more than ounce-counting.
For a down sleeping bag, the Nemo Disco 15 does a commendable job managing moisture. The shell fabric is treated with DWR, and Nemo reinforces the hood and footbox with a PFAS-free waterproof material. Those areas are especially prone to condensation in small backpacking tents, and the added protection makes a real difference between a soggy sleep and a dry, cozy one.
The Disco also contains hydrophobic down, which helps prevent moisture absorption and clumping. Of course, it’s still a down bag—if it gets truly wet, performance will suffer—but for dealing with tent condensation and damp environments, the Disco feels more resilient than many competitors. If you think your trip is going to be absolutely sodden, though, and that your bag may get wet, go with a synthetic option like the Marmot Trestles Elite Eco.
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Longevity
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Responsible Down
The Responsible Down Standard (RDS), developed by Textile Exchange, is the leading certification for responsibly sourced down and uses third-party audits throughout the supply chain to verify animal welfare, responsible farming practices, and safe working conditions. Recycled down is another responsible choice that helps reduce demand for newly sourced down while keeping existing materials in circulation. A green check mark indicates a product uses responsibly sourced or recycled down, a yellow check mark indicates the brand sources responsible or recycled down for the majority of its products but does not specify it at the product level, and a red X indicates the product does not use responsibly sourced or recycled down.
PFAS-Free DWR
Durable water-repellent (DWR) finishes can contain PFAS (per- and polyfluoroalkyl substances). These highly persistent “forever chemicals” are used in outdoor gear for their strong resistance to water, oil, and heat, but are linked to environmental contamination and a range of health concerns. A green check mark indicates the product uses a PFAS-free DWR, while a red X means the DWR contains PFAS.
Recycled Materials
Recycled materials are prevalent in outdoor gear, with nylon, polyester, wool, and down among the most common, but the composition varies widely. A green check mark indicates the product is made with a substantial amount of recycled materials (100% recycled or the core fabric that makes up most of the product is recycled), a yellow check means it contains a moderate to small amount of recycled materials, while a red X means there are no recycled materials in the product.
Bluesign Approved
Bluesign Technologies, based in Switzerland, operates a third-party textile management system that ensures materials are manufactured to strict environmental, chemical, and worker safety standards. A green check mark indicates a product is either a Bluesign Product (contains at least 90% Bluesign-approved fabrics and 20-30% Bluesign-approved accessories) or features a significant amount of Bluesign-approved materials. A yellow check mark means it uses some Bluesign-approved materials but less than the aforementioned category, and a red X means there are no Bluesign-approved materials in the product.
Responsible Manufacturing
This criterion evaluates a brand’s commitment to fair wages, safe working conditions, and reducing environmental impact through certifications and programs like Fair Trade Certified, Fair Wear Foundation, Worldwide Responsible Accredited Production (WRAP), and the Fair Labor Association, while also recognizing brands that manufacture primarily in the U.S. or Europe under strict labor and environmental regulations. A green check mark indicates a brand meets our responsible manufacturing criteria, while a red X means it does not.
Recycled and/or Reduced Packaging
Packaging can add significant waste to outdoor gear purchases, so many brands work to reduce its impact by using recycled materials, incorporating Forest Stewardship Council-certified paper products, and minimizing plastic and paper use. A green check mark indicates a brand uses recycled or reduced materials across all of its packaging, a yellow check indicates moderate or limited use of recycled or reduced packaging, and a red X indicates the brand does not make either of these efforts.
Repair Services
Repair services extend the lifespan of outdoor gear and reduce overall consumption, though programs vary widely. Some brands offer comprehensive repairs for a range of issues, while others provide limited or no repair support. A green check mark indicates a robust repair program, a yellow check mark indicates limited repair services, and a red X indicates the brand does not offer repair services.
Resale and/or Recycling Services
Resale and recycling programs help keep outdoor gear in circulation longer and out of landfills, ranging from trade-in resale platforms that offer store credit to take-back initiatives that recycle products at the end of their usable life. A green check mark indicates a brand offers both resale and recycling programs, a yellow check mark indicates it offers one or the two, and a red X indicates it offers neither.
Carbon Footprint Tracking
This criterion evaluates whether a brand measures, reports, and works to reduce its greenhouse gas emissions using established frameworks such as the Higg Index, Greenhouse Gas Protocol, or The Change Climate Project. A green check mark indicates a brand publicly reports greenhouse gas emissions data, sets clearly defined reduction targets, and uses established tracking frameworks such as Higg or The Change Climate Project. A yellow check mark indicates the brand tracks emissions and outlines reduction goals but provides limited data, lacks science-based verification, or does not clearly report progress. A red X indicates the brand does not appear to track greenhouse gas emissions or provides so little information that its efforts cannot be verified.
Annual Impact Report
Annual impact reports provide transparency and accountability by outlining a brand’s sustainability efforts across areas such as material sourcing, greenhouse gas emissions, waste, water use, supply chains, and packaging. A green check mark indicates a brand publishes a detailed, brand-specific impact report that closely aligns with our sustainability criteria and leaves little room for ambiguity. A yellow check indicates a brand provides some relevant sustainability reporting but lacks detail in key areas or is covered only briefly within a parent company report. A red X indicates a brand does not regularly publish an impact report.
I’m 5-foot-8, and I tested the Disco in the men’s regular size, which is rated for sleepers up to 6 feet tall. The fit was roomy, but that’s the point, and the Disco lands somewhere between a trim mummy bag and a semi-rectangular design. There was plenty of space at the shoulders and legs, which contributed heavily to the bag’s comfort.
Nemo offers a broad range of sizes, including Regular Wide, Long, and Long Wide options for men, as well as multiple women’s-specific cuts. If you know you want extra room, the Wide versions provide a lot of space without pushing the bag into full rectangular territory.
If you’re coming from a slim mummy bag, the Disco will feel spacious immediately. That extra room is a big part of its appeal—but also part of why it weighs what it does.
Big Agnes Sidewinder 20 ($330): A More Specialized Bag
The Sidewinder 20 is purpose-built for side sleepers, with a centered zipper that prevents rolling onto it during the night. While its shoulder girth is similar to the Disco’s, it tapers aggressively at the feet, offering far less room overall (whereas the Sidewinder is meant to turn with you, the Disco is roomy enough that you can turn inside of it). Both bags use 650-fill down, but the Disco packs in more insulation to achieve a slightly warmer ISO rating—at the cost of additional weight, though. Where the Disco really pulls ahead is features: The draft collar, vents, pillow pocket, and reinforced hood and footbox all help justify its higher price and weight. In the end, the Sidewinder feels more niche; the Disco feels more versatile. To learn more, check out our Sidewinder SL 20 review.
Nemo Riff Endless Promise 15 ($400): An Identity Crisis
The Riff shares the Disco’s hourglass shape and many of its best features, but upgrades to 800-fill down, trimming about 4 ounces off the total weight. It’s still over 2.5 pounds, though, and the packed size difference is negligible, so this is also a sleeping bag for relaxed backpacking trips rather than long-distance epics. The Riff also costs $100 more. In terms of interior space, the Disco offers noticeably more, particularly at the hips and knees, and feels more relaxed overall. Unless shaving a few ounces is a high priority for you, the Disco delivers better value, more room, and nearly identical warmth. For more, read our review of the Riff Endless Promise 15.
With an hourglass shape that provides plenty of room at the shoulders and knees, the Disco’s dimensions are a boon for side-sleepers. Ultra-soft materials and zippered vents add to the comfort-first design—at the expense of some extra weight.
Warmth / Weight
Comfort
Features
Durability
Water Resistance
Sustainability
The purpose-built Sidewinder is made for one specific group of backpackers: those who sleep almost exclusively on their sides. However, it’s not for everyone, and is middling in weight and packability.
Warmth / Weight
Comfort
Features
Durability
Water Resistance
Sustainability
The Riff pairs nominally weight-saving materials with a comfort-minded mentality, but the results aren’t spectacular. This bag feels great, but we wish it leaned into either its roominess or packability even more.
Warmth / Weight
Comfort
Features
Durability
Water Resistance
Sustainability
If you place a high premium on sleeping bag comfort (and to be honest, who doesn’t?), want room to move around while you sleep, and like smart temperature regulation—and you’re willing to carry extra weight to get it—the Nemo Disco Endless Promise 15 is a great sleeping bag choice. It’s ideal for weekend backpackers, side sleepers, and anyone who dislikes the restrictive feel of mummy bags. Given its hefty weight, it’s not a thru-hiking or ultralight specialist, but for shorter trips that are more about laid-back fun than obsessing about mileage, the Disco is an inviting bag to retire into at the end of the day.
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