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.
