How to Choose Sleeping Bags for Backpacking
REI Co-op Lumen Sleeping Bag
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With a relaxed mummy fit, this 3-season synthetic sleeping bag offers excellent compressibility, warmth and value.
Shop similar productsKey Details
Fill
Polyester fibers
Temperature Rating (F)
20 degrees (F)
- With a European Norm (EN) lower-limit rating of 20°F, this bag is suitable for 3-season use
- Synthetic polyester insulation is durable and highly compressible; the fill also retains some insulating ability if it gets wet
- Shingle construction with overlapping layers distributes insulation evenly and prevents cold spots
- Equally distributed insulation accommodates the multiposition sleeper; mummy shape is thermally efficient, yet roomy enough for sleeping comfort
- Durable ripstop nylon shell is water- and abrasion-resistant; nylon taffeta lining is soft and resists tears
- Relaxed fit through the shoulders and hips gives you room to move
- Contoured hood, insulated face muffler, roomy footbox and full-length zipper draft tube work together to keep heat in and cold out
- Bag has a stash pocket under the collar
- Pad loops provide attachment points to keep your sleeping bag and pad together (sleeping pad not included)
- Full-length zipper is backed by wide, antisnag binding tape
- Differentiated drawcords (1 round, 1 flat) allow quick hood and neck adjustments in the dark
- Nylon stuff sack and cotton storage bag included
- REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world
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. Our backpacking bags are rated for temperature according to an independent testing protocol: International Organization for Standardization (ISO) 23537. 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. For REI Co-op brand nongendered sleeping bags, we provide an overall temperature rating that falls between the Comfort and Lower Limit ratings.
View all REI Co-op 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. For REI Co-op brand nongendered sleeping bags, we provide an overall temperature rating that falls between the Comfort and Lower Limit ratings.
| Best Use | Backpacking |
|---|---|
| Tested Lower Limit | 20 degrees (F) - EN |
| Tested Comfort | 31 degrees (F) - EN |
| Temperature Rating (F) | 20 degrees (F) |
| Temperature Rating (C) | -4 degrees (C) |
| Shell | Ripstop nylon |
| Zipper Location | Left |
| Insulation Type | Synthetic |
| Fill | Polyester fibers |
| Fill Weight | Unavailable |
| Lining | Nylon |
| Sleeping Bag Shape | Mummy |
| Gender | Unisex |
| Sustainability | From a Climate Label Certified brand |
Buying Advice
Better gear is built together
From feedback to field testing, all of our gear is dialed-in by REI Co-op members. Their adventures informed every stitch and detail—making for better, longer-lasting gear.
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Carl K
Studio City, CA
A Worthy Upgrade...
8 years ago
I bought a 45º bag once. I'm not even sure why they make those. Well, that was before I really understood the rating system. Anyway, I'm super stoked about my Lumen sleeping bag. It was perfect for the trip I recently went on, and I'm sure it will be with me for a long time. I love the color and it fits nicely into my new Half Dome 2! It's cozy. Easy to get in and out of. I opted for the synthetic down because of price, moisture management, and I felt like this bag was a great balance of weight and effective heat retention/comfort. I feel like the stuff sac is a bit small, but I guess thats the idea and I need to just figure out the best way to cram my bag into it.
Yes , I recommend this product
MOWTIN
Maryland
MOWTIN REVIEW
8 years ago
Weighing roughly 3lbs, this synthetic polyester insulated bag was a total upgrade from our previous model. Ordered from REI.com, the bag came in promptly as always through REI's awesome free shipping with purchases over $50. On sale, this long-wide sleeping bag was purchased for $106 and some change + tax. To us explorers on a budget, this was a steal. The question is though....will it keep us warm? The answer is yes. Rated at -12 Degrees (F) as its Lowest Survival Rating and 20 Degrees (F) as its Comfort Rating, this bag is true to its word. (**Temperature Ratings are based from Women's Body Temperature when using the bag because studies show that Women have a lower body temperature than Men when put in the same environment) Wearing ONLY underwear in temperatures less than 20 Degrees (F), we stayed nice and toasty thanks to the mummy design, the insulated hood, and the adjustable face hole. As far as size goes...I'm personally 6' 4'' and this Long-Wide bag left me plenty of wiggle room all the way around. On warmer days I lay on top of the sleeping bag and once I get chilly, with help of the zipper "no-snag" design, I'm able to literately get in this bag in my sleep. Presenting another great REI Co-op product. Yet again, REI proving why we are life-time members!! Guaranteed to recommend this product and other REI sleeping bags to anyone looking for one! **recommendation for explorers. keep sleeping bag stored in its included cotton bag versus the stuff sack, once out of the stuff sack, shake out the sleeping bag and get the insulation nice and loose to keep you warmer!
Yes , I recommend this product
Crazy Jack
San Diego, CA, United States
Cozy, comfortable, and a bit cold
10 years ago
I bought this bag recently for a road trip which ranged from Los Padres to Lake Tahoe to Yosemite. The first few nights I slept fantastically well - the bag is roomy, plush, and on those warmer nights, very comfortable. The last few nights we spent in Yosemite were much less pleasant. Even though the temperature at nights stayed about the recommended cold temperature, I still had to pull in extra jackets and blankets to keep warm. Maybe I'm a cold sleeper, but I really wish this bag was just a bit warmer. I love that the mummy style also gives you room to move around, and that it packs so light and easy.
HammerDad
Redlands, CA, United States
Love this bag!!
10 years ago
Got this bag as my wife, son and I prepare to hike through Lassen and Redwood. I took it out on a test hike in the local mountains, where it got to the low 30's. This bag was great! The minute I got in I could feel it begin to warm up. Moving around a little helped generate more heat to keep in. The only gripe I have is that the pull to close around your head isn't as snug as I'd like, but it didn't let in a lot of cold air so it's no big deal. I didn't experience any cold spots on this bag. It compresses down nicely and isn't heavy.. I really like this bag and I strongly recommend it.
Yes , I recommend this product
termer
TN
Great Bag!
8 years ago
I just got this bag and I'm very pleased. I have slept outside twice in it.. First nite was 28 degrees and second nite was 22 degrees. Bag did an excellent job keeping me warm consirdering i was only in shorts and long sleeve shirt. The 22 degree morning i woke with frost covering the entire bag and i was completely dry and warm inside. I got the long/wide bag (Im 5'10, 220) and im not disappointed at all, I'm a side sleeper and it provides enough room for me to sleep comfortably and still got room to spare. I like being able to attach my sleeping pad directly to my bag so im not waking up off the pad. With proper sleeping attire and a bag liner I'm sure i can sleep in colder temps.
Yes , I recommend this product
OldBull
Vero Beach, FL, United States
First Impressions
10 years ago
Nikie in customer service pointed me toward this bag due to my size requirements. I have a 55" girth and 48" chest. Normal mummy bags are too constricting. Received the bag it looked huge in box. Laid it out and LOVE it already, I can actually move in it. I am a side sleeper. It stuffs down very well and fits in bottom of 65L pack with room to spare. Look forward to using it on the AT next week. Will Followed
Yes , I recommend this product
Caver-Dave
SF Bay Area, California
Light weight and comfortable, but could be warmer
10 years ago
I just bought this bag for a four day trip in the mountains in spring time. It was light weight, easy to pack, and was a good fit. The temperatures at night were in the high 30s. At this temp, even with a good mattress pad, it was a bit cool. I had to pull a bunch of extra clothes into the bag to keep my legs warm.
Yes , I recommend this product
Bend
Bend, OR, United States
Warm bag, good compression
10 years ago
Kept me toasty when the temp was in the lower 30s. Nice compression. I wanted a synthetic bag because of backpacking in wet and stormy conditions. It weighs just eight ounces more than my Marmot down bag. FYI, I weighed my 'regular' size bag, and it weighed 2 ounces more than the spec. It weighs 2 pounds 10 ounces on my precisely accurate scale. The spec. says 2 pounds 8 ounces.
Yes , I recommend this product
Alex Malson
Northern California
Good piece of gear at a great price
9 years ago
Bought this bag in Nov. just used it on a backpacking trip in Joshua Tree and loved it; wasn't cold at all in fact had to sleep with the bag partially unzipped. It was in the mid 40's at night on this trip so I really didn't get to test it at the low end of the recommended temp, but I would recommend this bag. It's fairly roomy and comfortable to be in. Also love that I can zip it to my wife's bag as well ;-). So I say it again "good piece of gear at a great price! -Hiking is life, the rest is just details!-
Gadget Girl Scout
Austin, TX
Excellent value
8 years ago
I'm in the process of collecting backpacking gear for my tall seven year old. I don't want to spend a ton of money on stuff that is either a) bad quality, b) poor function, or c) won't hold up to standard kid abuses (within reason). I wanted to get her a 30* bag that didn't weigh a ton and that had some way to secure a pad, because she rolls all over the place at nighttime. This bag does the trick well. She has reported it to be comfy and warm. The synthetic insulation means if she spills her water bottle on it the indicative value isn't gone. My only complain is it's a little bulky, but that is expected for synthetic insulation, and it's pretty snug in the stuff sack. I got mine from the REI Garage for a great price. I'm very satisfied with my purchase.
Yes , I recommend this product
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