How to Choose Sleeping Bags for Backpacking
Anacortes
Sea to Summit Alpine -20F Down Sleeping Bag
$934.00 – to $984.00
Gear up for high-altitude or colder-latitude adventures with the Sea to Summit Alpine -20F down sleeping bag. It offers ample space for gear, and the zip system provides ventilation and versatility.
Key Details
Fill
850+ fill-power goose down
Weight
3 lbs. 3 oz.
Compressed Volume
Regular: 12.6 liters
Long: 14 liters
Temperature Rating (F)
-20 degrees (F)
- RDS-certified, 850+ fill-power goose down with a non-PFAS Ultra-Dry Down treatment for maximum thermal performance
- Recycled 20-denier nylon shell with non-PFAS durable water repellent (DWR) is light and durable
- Hood and footbox have a highly water-resistant, breathable fabric for extra moisture protection—ideal for bivys or snow caves
- Highly breathable liner for enhanced comfort
- Roomy, expedition mummy fit provides plenty of space for you, your performance clothing and gear you don't want to freeze
- Free-Flow Zip System features a full-length zipper with a half-length zipper on the opposite side for excellent temperature regulation
- Technical hood and footbox, efficient mummy shape and generous draft tubes on the zippers maximize warmth retention
- Sea to Summit Guarantee is offered for the Lifetime of this sleeping bag
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 Sea to Summit 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 | Backpacking |
|---|---|
| Tested Lower Limit | -20 degrees (F) - ISO |
| Tested Comfort | -2 degrees (F) - ISO |
| Temperature Rating (F) | -20 degrees (F) |
| Temperature Rating (C) | -29 degrees (C) |
| Weight | 3 lbs. 3 oz. |
| Shell | 100% RCS recycled nylon (hood and footbox non-recycled 10D nylon) |
| Zipper Location | Left/Right |
| Insulation Type | Down |
| Water-Resistant Down | Yes |
| Fill | 850+ fill-power goose down |
| Fill Weight | Regular: 3 lbs. 3.5 oz. Long: 3 lbs. 10 oz. |
| Sleeping Capacity | 1-person |
| Lining | 100% RCS recycled nylon |
| Sleeping Bag Shape | Mummy |
| Fits Up To (in.) | Regular: 72.5 inches Long: 77.5 inches |
| Shoulder Girth (in.) | Regular: 62 inches Long: 66.9 inches |
| Hip Girth (in.) | Regular: 58.7 inches Long: 62.6 inches |
| Stuff Sack Volume | 26 liters |
| Compressed Volume | Regular: 12.6 liters Long: 14 liters |
| Gender | Unisex |
| Sustainability | Down certified to the Responsible Down Standard (RDS) Contains recycled materials |
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Customer Images
3 weeks ago
QUALITY . . . shelter for Sierra High Route
[This review was collected as part of a promotion.] Traveling in the High Sierras during winter can be challenging, as weather conditions can shift from problematic to critical very quickly. To manage these risks, I treat every trip as a calculated journey rather than a gamble against nature. My core gear for winter Sierra High Route treks includes: 1. Sea to Summit Alpine -20F long sleeping bag 2. Inflatable 7R insulated sleeping pad 3. Two-person, 4-season tent The key to safety is transitioning quickly from hiking to a secure, dry shelter. On days when I am exposed to the elements or forced to set up camp in difficult conditions, the Sea to Summit Alpine bag is essential. Even when I am wet and cold, jumping into this bag provides immediate warmth and security. I have found this bag to be incredibly durable and reliable. Even after tears and split seams, the Sea to Summit repair team has restored it to excellent condition. I gladly carry the extra weight for the -20F rating because it serves as my security blanket in harsh environments. Along with my 4-season tent, this bag is my most important investment for safely exploring remote routes. Happy trails and stay safe, W1SPR
Review originally posted on Sea to Summit
3 days ago
Extremely comfy but cold
Amazingly comfortable, roomy, and light for backpacking. I used it in DNP last winter in -15 and froze. Had to have a belay parka, puffy pants, booties on in the bag.
Review originally posted on Sea to Summit
Height:6'3"
Age:35–44
Weight:200–225 lbs.
1 year ago
Warm and cozy
So cozy. While I knew I wasn't going to be camping in -20 degrees anytime soon I purchased it to replace my old zero degree bag. So far I've only tested it in temperatures of about 12 degrees F but it was so warm while only wearing shorts to sleep in. I mostly purchased this item due to how roomy it presented and I was not disappointed.
Height:6'3"
Age:35–44
Weight:200–225 lbs.
1 year ago
Sleeping bag
[This review was collected as part of a promotion.] Going to use in BC canada in August till October. It feels great I thought. will give futher review when I get back
Review originally posted on Sea to Summit
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