How to Choose Sleeping Bags for Backpacking
NEMO Sonic 0 Sleeping Bag
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Stay cozy on frozen mountain bivouacs in the 800-fill-power down comfort of the NEMO Sonic 0 sleeping bag. Adjustable Thermo Gills™ regulate temperature without letting cold drafts in.
Shop newer versionKey Details
Fill
800-fill-power hydrophobic down
Temperature Rating (F)
0 degrees (F)
- Overstuffed with hydrophobic, PFC-free down; Responsible Down Standard (RDS) certification ensures humane treatment and traceability throughout the supply chain
- Waterproof/breathable Toester™ footbox is shaped for foot comfort; it has a layer of synthetic insulation to help eliminate cold spots
- 20-denier ripstop nylon shell fabric and 30-denier nylon taffeta lining feature durable water repellent (DWR) treatments to shrug off moisture
- Redesigned draft collar and draft tubes provide a secure barrier against cold air; offset zipper creates a thermally efficient seal
- Contoured hood with drawstring cord maximizes thermal efficiency
- Stretch construction at the knees allows side sleeping
- Updated profile holds warmth closer to your body
Imported.
Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Backpacking bags are typically rated for temperature according to an independent testing protocol—currently International Organization for Standardization (ISO) 23537, though some older items followed European Norm (EN) 13537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.
Each bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
View all NEMO Backpacking Sleeping BagsEach bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
| Best Use | Mountaineering |
|---|---|
| Tested Lower Limit | -1 degrees (F) - EN |
| Tested Comfort | 14 degrees (F) - EN |
| Temperature Rating (F) | 0 degrees (F) |
| Temperature Rating (C) | -18 degrees (C) |
| Shell | 20-denier ripstop nylon |
| Zipper Location | Left |
| Insulation Type | Down |
| Water-Resistant Down | Yes |
| Fill | 800-fill-power hydrophobic down |
| Lining | 30-denier nylon taffeta |
| Sleeping Bag Shape | Mummy |
| Stuff Sack Volume | 13 liters |
| Gender | Unisex |
| Sustainability | Down certified to the Responsible Down Standard (RDS) |
Buying Advice
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Needmorewarmth
Olympia
Cold area below waist
3 years ago
I tested this bag in my back yard, in the snow, 28 degrees, in my REÍ Arete 2 tent, with good thermal pads underneath me. From the waist up, I was toasty warm, but from the waist down, I was cold. Despite wearing a thermal base layer plus a mid layer fleece, I could feel cold air on my legs. When I reached my hand down to feel the inside of the bag around the level of my knees, the bag felt cold, almost as cold as the exterior of the bag. I gave it a full 2 hours before I gave up the test. My feeling it that there is plenty of insulation in the top of the bag, but not enough in the lower half. This is going back as my intention is to purchase a bag that will keep me comfortable in the teens.
Age:55–64
Weight:175–200 lbs.
Height:5'11"
No, I do not recommend this product
THEZAC
Asheville NC
Glad I bought it
5 years ago
Bought this for Self-support kayaking the Grand Canyon in Jan. Packs down small enough to fit in dry bag but expands to fit my wide shoulders and 6 foot 200lb frame. Far roomier than my last bag. Went to sleep in 40 degrees and was not too hot but then, as I slept outside with no tent, it dropped to 20 degrees. Was curious how it would do. Woke up with frost covering my bag and was still warm in my cotton PJ's and no socks. See exactly why it was chosen as gear of the year. Looking forward to NOT freezing at night on the Grand.
Yes , I recommend this product
Originally posted on nemoequipment.com
roomd
Very comfortable
5 years ago
I'm a side sleeper and this is the most comfortable and roomy sleeping bag I've ever had. Finally, I can get a decent sleep on my backpacking and mountaineering outings! Holds cold temps fairly well, I slept at about 5-10F for a few nights wearing my base layer and it was good enough. But again, roominess compared to an average mummy bag is the most striking feature of this bag. Highly recommended to any sleeper who need a bit more space for their legs (even with a few items like gloves and mittens that I've put there to keep warm and dry overnight).
Yes , I recommend this product
xsimmiesx
Yosemite National Park
Lightweight Warmth
5 years ago
Purchased this bag for snow camping and ended up using all season long! The bag is light, versatile, and built for adventure. My first trip with this bag was ski touring to Tuolumne Meadows from Yosemite Valley and the bag delivered. After this trip I continued to use it because of how light it was compared to my Verde 20 synthetic and thank goodness for the vents! Even when it’s 40-50f I’m able to open the vents and be quite comfortable. One problem I have encountered is how hot the waterproof foot box got while sleeping in my OR Bivy. (However my feet are almost always hot) Great product would recommend 10-10
Yes , I recommend this product
Originally posted on nemoequipment.com
rr21
Horrible damp, fishy, ducky smell.
3 years ago
I ordered 2 of these sleeping bags for my spouse and myself for upcoming winter backpacking trip. Both sleeping bags smell horrible right out of the box - fishy, damp, ducky smell. If I sleep with that backpack near my head and neck, I will throw up right away. We vented the sleeping bag over multiple days and entire sleeping bag still smells terrible. This looks like a poor quality control on Nemo's side. Duck down is not cleaned properly or has some bacteria/bad stuff in it. Now our home area where bags were venting smells bad. This was a horrible experience and our backpacking trip is in 3 days. REI customer service was good and agreed to send replacement with expedited shipping. We will see if we get lucky with the next Nemo shipment.
No, I do not recommend this product
Anonymous
Vermont
The Most Comfortable Bag I’ve Owned!
5 years ago
The Sonic has accompanied me on a backpacking trip in Wyoming, a 2-week camping trip throughout the west (in below freezing temps), and several backcountry ski trips this winter, once in -10 degrees F. So far, there are no conditions that I haven’t been comfortable in using my Sonic. It is also the most lightweight and packable bag I’ve ever owned. I can’t say enough about the Sonic.
Yes , I recommend this product
Originally posted on nemoequipment.com
Taylorleighhhh
Broinfield, Colorado
Use it all the time!
5 years ago
I was worried about getting a 0degree sleeping bag but living near the mountains and being that’s where I’m using it mostly, I decided to make the investment and go with something that will get me through some freezing nights since I get cold easily. With the gills and option to unzip partially it is a all-season bag for me! Super comfortable glad I bought it, I’ll have it forever
Yes , I recommend this product
Originally posted on nemoequipment.com
Anonymous
Omaha, NE
Used on Kilimanjaro Climb
5 years ago
Both my wife and I purchased the -20 Sonic bags in regular lengths and just used them on an October 2019 climb up Mt. Kilimanjaro. We both enjoyed the bags, and while the temperatures didn't get that low, it was reassuring that we would be prepared if a cold snap did hit us. We did have quite a bit of rain and several mornings we had heavy condensation inside the tent, and the extra waterproofing material on the footbox helped to keep the down from getting wet wher our feet touched the tent walls. I'm 5'9" and 195 lbs and I wear a 44" dress coat, I had a hard time getting the bag zipped up all the way to the top. If it had maybe just another 2 inches in shoulder girth, I would have an easier time contorting myself to fully zip the bag. I'm a side sleeper, and was able to sleep in the bag, but not as easily as in my older Nemo Nocturne 15 bag. I would also like to have the option for a right hand zipper. Overall, great bag and another quality Nemo product.
Yes , I recommend this product
Originally posted on nemoequipment.com
jhubbel
Denver CO
a perfect bag
5 years ago
I took this bag to the Northern Rockies for a month on a horse packing trip, then for five weeks to early-winter Mongolia. I was warm, comfy and comfortable the whole time. Hardest part of my day was getting up in the morning. I love this bag. Worth the extra weight, especially if you sleep cold like I do.
Yes , I recommend this product
Originally posted on nemoequipment.com
Thomas
Well designed, but cold.
6 years ago
Bought this a few months ago, tested it in temps down to about -5 and the bag felt pretty cold... I realize loft isn't everything when it comes to temp ratings but bags with the same amounts of loft (7") from other U.S. manufacturers are only rated at about 0 degrees F. Not -20... I bought this hoping I'd be able to use it for a Denali climb, but I'm afraid it's not on par for that despite supposedly having a -20 degree rating. Guess there's a reason other bags with similar ratings cost significantly more. It's otherwise a very comfortable bag, and well designed.
Originally posted on nemoequipment.com
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