Reviews You Can Rely On

Western Mountaineering Alpinlite 20 Review

western mountaineering alpinlite 20 backpacking sleeping bag review
Credit: Western Mountaineering
  • 1
  • 2
  • 3
  • 4
  • 5
Price:  $585 List | $625.00 at Backcountry
Compare prices at 2 resellers
Pros:  Excellent loft, no catch zipper, warm, comfortable, lightweight
Cons:  Expensive, very warm for mid-summer, weak velcro closure for draft collar
Manufacturer:   Western Mountaineering
By Mike Phillips ⋅ Review Editor  ⋅  Nov 22, 2015
Our Editors independently research, test, and rate the best products. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Learn more

Our Verdict

The WM AlpinLite is a slightly wider version of the Editors' Choice award winning Western Mountaineering Ultralite. The wider cut of the Alpinlite makes it more suitable for wider shoulders and those who are willing to sacrifice a few ounces for a more comfortable fit. The Alpinlite features a respectable 5" of loft and continuous baffles to shift down around in order to suit the conditions. The bag is compressible and lightweight thanks to high quality down and excellent exterior fabric. Western Mountaineering bags have great no-catch zippers that are reliable and easy to slide. Overall, this bag is an excellent choice for the not quite ultra-light backpackers and climbers looking for a high quality, made in the USA down sleeping bag for three season use in the mountains.

Our Analysis and Test Results

Testers agree that the Western Mountaineering Alpinlite is a great sleeping bag for the weight conscious but not quite ultra-light backpackers and climbers who want a comfortable and versatile 3 season down sleeping bag.

Performance Comparison

western mountaineering alpinlite 20 backpacking sleeping bag review - two traditional mummy style bags: the western mountaineering...
Two traditional mummy style bags: the Western Mountaineering Alpinlite (red) and Ultralite (blue) in a side by side comparison. See how they are both a tubular, comfortable shape and have hoods. You can see that the roomier Alpinlite leans towards even more comfort than the Ultralite.
Credit: Mike Phillips


Warmth is primarily determined by the amount of loft and the fit of a sleeping bag. The Alpinlite is rated for 20 degrees Fahrenheit but testers agreed that this felt a bit conservative. In near freezing temperatures above 11,000' the bag was cozy without the draft collar or hood cinched down. In warmer sub-alpine terrain, the bag could be unzipped a little bit for a more comfortable sleep.

Testers who used this bag were narrow shouldered and generally found this bag to be roomy but comfortable thanks to the extra space around their upper body. Surprisingly this did not drastically affect the perceived warmth of the Alpinlite when used in temperatures above its advertised 20 degree rating. Skinnier users will also appreciate the extra room to layer more clothing for those chilly nights in the fall. If you prefer a closer fit for more warmth and less dead air space, try the slimmer-cut Ultralite, which is a slightly narrower and lighter version of this bag, which wins our Editors' Choice award.

We feel that this bag is best suited for cooler mountain environments and will remain warm when used in the shoulder seasons of spring and fall especially with warm clothing on.


The Alpinlite weighs two pounds in the 6'0" option which is a very respectable weight for a bag as warm as it is. It features top quality Extremelite fabric on the top and bottom of the sleeping bag. This fabric weighs less than 1 oz. per square yard and is very compressible. The lightweight fabric makes this bag slightly more fragile than heavier bags with more durable fabrics; so take care! Western Mountaineering uses 850+ fill down which allows them to fill the down chambers to keep you warm and keep the weight down. Western Mountaineering bags are simply functional by design. They are fairly traditional mummy style sleeping bags that use high quality materials and limit features to the highly functional to save weight.


With 5 inches of loft the Alpinlite is like sleeping wrapped in a three season cloud. It has just enough down to keep you warm at high mountain campsites and continuous horizontal baffles to allow you to shift down around to make warmer nights more comfortable. The extra shoulder girth allows for a better fit for bigger people, and allows narrow shoulders to move more freely and layer up for colder late season conditions. A two pound or less sleeping bag is a reasonable goal for weight conscious backpackers who want to carry a lighter pack on extended trips or demanding terrain.

western mountaineering alpinlite 20 backpacking sleeping bag review - the alpinlite features substantial loft for a 3 season bag. the...
The Alpinlite features substantial loft for a 3 season bag. The small velcro closures for the hood and draft collar are shown here.
Credit: Mike Phillips


The continuous horizontal baffles on the Alpinlite make for an easy to use thermostat. The down chambers encircle the sleeping bag from zipper to zipper allowing the user to shift down toward the top of the bag for cold nights and shift the material beneath the bag for warm nights. By opening the bag and laying it flat, you can press down and run your hands in the desired direction, pushing insulation to where you need it less.

western mountaineering alpinlite 20 backpacking sleeping bag review - the continuous horizontal baffles on the alpinlite allow for...
The continuous horizontal baffles on the Alpinlite allow for adaptation to the temperature.
Credit: Mike Phillips

The Alpinlite features a reverse differential hood which is very comfortable. This means the fabric on the inside of the sleeping bag being larger than the shell fabric. The hood can cover your head comfortably without needing to cinch it too tight. Tightening the hood on some sleeping bags is uncomfortable and can be claustrophobic for some people.

The one inch stiffening tape that Western Mountaineering uses on both sides of their zippers aids in easy, snag free exits from the bag at night when nature calls.

western mountaineering alpinlite 20 backpacking sleeping bag review - the stiffening tape on the zippers of the alpinlite provides...
The stiffening tape on the zippers of the Alpinlite provides snag-free performance.
Credit: Mike Phillips

Simple, functional extra features and high quality materials make the Alpinlite an exceptional three season sleeping bag and help keep the weight down.


A 3 season sleeping bag should be versatile by definition. It can be your single go-to bag for adventures during most of the year in a variety of environments. The Alpinelite shines as a prime example of that desire for a do-it-all sleeping bag. It is light enough to be part of a weight conscious backpacking kit, comfortable enough for long trips and long seasons sleeping in a sleeping bag most of the time, and warm enough to be used in the shoulder seasons without concern. Layer up in this bag and it can handle late fall and mild winter conditions.

Best Application

The Alpinlite is an excellent 3 season sleeping bag which is best suited for summer backpacking in the mountains and shoulder season backpacking and mountaineering trips. Weight conscious backpackers will appreciate the Alpinlite weighing in at two pounds or less and being highly compressible. It is warmer than its 20 degree rating and its slightly wider shoulder girth will accommodate wider shoulders and extra clothing layers for the shorter days and falling temperatures of late fall trips in the mountains. This bag is a comfortable choice for people who sleep in a sleeping bag more often their own bed (ie: guides, outdoor educators) who need one bag to handle the entirety of a busy summer season.


High quality down sleeping bags have a long lifespan if they are well taken care of. Down maintains it's insulative qualities after years of compressing and unstuffing sleeping bags over and over while out on the trail. Good three season bags like the Western Mountaineering Alpinlite are especially valuable because you can have one bag that can be used on a variety of trips, across different seasons and in different environments.

Price is always a factor, no matter the purchase. At $500+ for a Western Mountaineering Alpinlite, the high price is definitely a factor. Sleeping bags are big investments gear wise, and finding bang for your buck, is really important. If you spend a lot of time in a sleeping bag, or have the money to invest in a single three season sleeping bag to keep you warm most of the year, we think it is worth it to spend the extra money on the Western Mountaineering Alpinlite.


The Western Mountaineering Alpinlite is well respected for being a comfortable, light-weight and versatile 3 season sleeping bag. This bag is right at home at mid to high elevations during the summer and will excel on shoulder season backpacking and mountaineering trips. We like that the sleeping bags from Western Mountaineering are made in the USA and they continue to pay attention to important design details. These bags are expensive but worth the extra money for the performance they provide and the fact that high quality down products can last a long time with ongoing care for them.

Mike Phillips
You Might Also Like

Ad-free. Influence-free. Powered by Testing.

GearLab is founded on the principle of honest, objective, reviews. Our experts test thousands of products each year using thoughtful test plans that bring out key performance differences between competing products. And, to assure complete independence, we buy all the products we test ourselves. No cherry-picked units sent by manufacturers. No sponsored content. No ads. Just real, honest, side-by-side testing and comparison.

Learn More