Western Mountaineering AlpinLite 20 F

Priced: $484.95 - $554.95 Rated:   - 5 stars out of 5 by 12 reviews.
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Western Mountaineering AlpinLite 20 F -
Climbing or traversing technical pitches with a massive load dangling behind you is a bad way to go through life. Western Mountaineering created the Alpinlite 20-Degree Down Sleeping Bag for alpine climbers and weight-obsessed backpackers who demand top-shelf quality and bottom-line weight savings. Though it packs the warmth of 850-fill goose down and a full draft collar, the Alpinlite 20 weighs in at just over a pound.

Lining and Layers:

  • Wider shoulder girth allows for extra layering in colder environments


  • (w/ full collar)


  • Highly breathable nylon shell fabric expels perspiration so that it doesn't condense in the down insulation and cause it to clump


  • Fill Wt.
  • Ultra-premium 850-fill down insulation retains your body’s warmth and provides a higher warmth-to-weight ratio than any synthetic-fill insulation
  • Continuous baffles and a down-filled collar prevent energy-sucking drafts from zapping your slumber


  • Stuff Size
  • Full-length #5 YKK Zipper


  • Western Mountaineering bags are made in the USA


  • Long
  • Loft
  • (163/140/99 cm)
  • 7 x 13 in
  • 21 oz (595 g)
  • 6'0" (180 cm)
  • (878 g)
  • Shape
  • 2 lb 1 oz
  • Regular
  • (935 g)
  • Inside Girth
  • 20° F (-7° C)
  • (160/142/99 cm)
  • 5 1/4 inch Spacing/Continuous Baffles
  • (18 x 33cm)
  • 5" (12.5 cm)
  • 6'6" (200 cm)
  • 8 x 15 in
  • 63"/56"/39"
  • (880 g)
  • 17 oz (480 g)
  • shdr/hip/foot
  • (165/142/99 cm)
  • Temp. Rating
  • 64"/55"/39"
  • (20 x 38cm)
  • Mummy
  • 5'6" (165 cm)
  • Total Wt.
  • 65"/56"/39"
  • Short
  • 19 oz (535 g)

The Western Mountaineering AlpinLite Sleeping Bag is wide, warm, and packed with features. With a 3-dimensional full down collar, a full-length YKK zipper, and 5 inches of loft, the Alpinlite has quickly become a popular model. The award winning Ultralite has been a favorite among lightweight backpackers for more than a decade, and the Alpinlite is just a wider version of that great bag. There are many 20 degree down mummy bags on the market, but none have the width, warmth, or loft of this bag.

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Average Price History: Price History
Review RatingNumber of Reviews
Fill Weight:19 oz / 539 g
Foot Girth:39 in
Hip Girth:55 in
Insulation:850 Fill Goose Down
Insulation Type:800+ Down Insulation
Max User Height:5 ft 6 in (Women's Regular), 6 ft 0 in (Regular), 6 ft 6 in (Long)
Shoulder Girth:64 in
Temperature Range:11° to 20°
Temperature Rating:20°
Weight:1 lb 15 oz / 0.88 kg (Regular)
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Subcategories of Sleeping Bags & Pads:

Western Mountaineering AlpinLite 20 F Reviews:


I'm 6'1" 225 and this is the perfect bag. I considered an Ultralite 20 but VERY happy I went with this instead. I need the room to turn & like the option to keep other clothing inside for something warm to wear in the morning.
I used it inside a double walled tent with a Thermarest Z-Lite SOL Sleeping Pad underneath. I wear merino wool socks inside mine along with "whatever" choice of long underwear as it was in the 20's where I lived. I was in my backyard & just wanted to test everything out. I also wore a 80% polyester/20% nylon blend balaclava; Cordura from Ranger Joes (that I noticed was surprisingly better than the merino wool offering from Smartwool)
Staying warm was not a problem in this bag, and I did not cinch up the available ties (there was no need as I had on a balaclava) No cold spots, even when my heels came off the mat & were in direct contact with the freezing tent floor I'd barely notice it, but I did have to scoot back up on the mat where I belonged. I can't tell you from experience (as it is very rare to get into the teens here temp wise) but I have a confidence I could have done so, but I bought the bag for a 20 degree rating only because that's the worst it gets around here & even then its only for a few days max.
The only gripe I had about my night was traffic noise on the adjacent highway I was not used to hearing from inside the house

chap838258 at Backcountry.com on 12/15/2013

I absolutely love this bag and would have kept it if I was bigger. I was initially torn between the Ultralite and Alpinlite, and ended up with getting the Alpinlite first. After some time in that bag I just found there to be too much dead air from the extra girth, but the Ultralite was snug to the point where I was worried about down compression if I had layers on. I returned the Alpinlite for the Versalite since it fit more snugly and rolled with me when I slept.
While the Versalite is slightly warmer than the Alpinlite or Ultralite bags, the chest girth sizing falls between the Alpinlite and Ultralite, which was perfect for me. The full length zipper allow for easy venting and I have no worries of overheating—I generally sleep very warm. The Versalite also comes with one more ounce of down than the Alpinlite, but is slightly narrower and thus warmer overall and spans a wider degree range. The full length zipper also allows the bag to be opened up and used like a quilt in warmer weather. I have taken both bags down to low 20s and the high teens and slept comfortably in a baselayer with the neck baffle completely loosened in the Versalite. The Alpinlite required me to cinch down both to trap in heat to fill the dead space.
The materials are top notch, the down is super lofty—WM bags are great.

Mike at Backcountry.com on 01/31/2012

6'5", 235lbs. Wear a 50L jacket, 34-36 inseam and waist. My arms aren't huge but they won't fit into the "check your blood pressure" thing at Walgreens. Point is, I take up some space.
The Alpinlite was perfect for my size. I move around a bit and never once felt claustrophobic, but I can't imagine having less space. I think I would have been freaking out in Ultralite. The 6'6" version of this bag couldn't have been a better fit. I never got cold at altitude and only got hot once at lower levels, but it was around 50* and I was still wearing a shirt and shorts so that one was on me. All it took was unzipping the bag a bit and it regulated nicely.
I thought I was crazy dropping almost $500 on a bag but this thing is absolutely awesome and it shows in the details: the stuff sack is perfectly sized and the zipper has smart things like a stiff backing so that you don't catch the bag in the zipper. I can't say enough great things about this bag.

Chris Rikli at Backcountry.com on 07/12/2012

Only used it twice but I love the fit. I'm 5'-2" and the bag fits perfectly with some room to spare for extra layers at the bottom.
My first trial was at the base of Mt Washington and the outside temp had dropped into the low 30s. I was cold with my base layers on but I run cold.
The second trial was in VT and the outside temp was in the 50s and damp. I was a bit too warm in the base layers on but boxers & undershirt was just right.
The only downside I experienced with the bag is the smell it gives off in damp conditions. The down smell can be a bit much even if the bag isn't directly wet.
Overall love the bag!

Jay S at Backcountry.com on 09/28/2011

I have been running the Alpinlite for a few years now. I really like the warmth and lack of weight.
The width is a bonus for me, as I am rather broad across the chest(44 coat size)and am a side sleeper.
I haven't had this bag much below 15*F, but in those cases it was still very warm-I have a hunch I could go into the high single digits with just a base layer and wool cap sleeping in the Alpinlite.
I will never part with this sleeping bag.

Tim at Backcountry.com on 08/23/2012

I love this bag. It has been warm on nights in a makeshift shelter in the 30s. I would feel comfortable taking it down towards that rating in a tent, but not really in a makeshift shelter. Quality of the bag is nice. Packs down small, zippers don't snag often, fabric and baffles feel good. Low weight, yet doesn't feel constricting. Nice bag! Plus made in the USA!

Alex at Backcountry.com on 06/05/2013

This is a premium bag. It's a mummy bag, but it's wider than a traditional mummy... which is great for those of us that like to move around while sleeping. It's very warm however, and has some cool features. It has excellent loft and compresses nicely. I have a full video review at backpackersreview.com

BackpackersReview.com at Backcountry.com on 03/20/2012

This bag is great quality! Western Mountaineering kills it when they make sleeping bags and this bag is as awesome as it sounds, it does, like all down bags, loose down throughout its adventures. All around great bag though except expensive but you get what you pay for!

Shawn Cash at Backcountry.com on 08/04/2013

Finally a warm and light sleeping bag for big guys that doesn't fit like a condom. Field tested it this autumn in the Dolomites in Italy in open air around freezing temperatures. Didn't need long underwear to keep comfie. Great product, fully worth the price.

Freek Strebe at Backcountry.com on 11/08/2011

Truly one of the favorite pieces of gear i own. Super warm, super light, super packable, super high quality construction. What else is there really to say about a sleeping bag? Outstanding in all regards!

brap733430 at Backcountry.com on 11/20/2013