Western Mountaineering is considered by many to manufacture the best sleeping bags in the world. The quality of their products is outstanding and it is designed with the requirements of hardcore ultralight backpackers, winter backpackers, and mountain climbers in mind.

A few weeks ago I decided to replace my REI Sub Kilo 20 which never performed up to its temperature rating. Based on the emphatic recommendations of some of my Twitter and Whiteblaze.net friends, I decided to make the extra investment and purchase the Western Mountaineering Ultralite 20, shown below. Western Mountaineering bags are priced at a premium, so "investment" is the appropriate word. 

Western Mountaineering Ultralite 20 Sleeping Bag

The Ultralite 20 is a mummy style bag rated for 20 degrees and contains 900 fill goose down. The 6 ft. model weighs 28.7 oz and has 5 inches of loft. The fit of the bag is fairly snug, particularly around the shoulders, with a girth of 59".  It also has a draft collar, which seals across your chest to prevent heat loss from the "bellows effect" when you move around at night. This is a very unusual feature on a 20 degree bag and something you usually only find on winter bags with a temperature rating of 0 degrees or lower.

Snag Proof Zipper, Western Mountaineering Sleeping Bag

One of the issues I had with my old Kilo 20 was that the zipper snagged constantly. On the Ultralite, there is a 2 inch strip of nylon on either side of the zipper that runs facing your body up the entire length of the bag and prevents the zipper from snagging. You can see a closeup of this protective barrier in the photo, above. It’s amazing: the zipper never snags. Ever.

I field tested my new Ultralite 20 this past weekend on a 3 night, 40 mile hike of the Long Trail in Vermont. The nights were a lot colder than we expected, with temperatures dipping into the mid-30’s. The Ultralite perfromed brilliantly. I was warm every night and far warmer than I ever was in my Kilo 20.

On the first night of my trip, I remember slipping into the Ultralite. Within 2 minutes I felt this incredible warmth envelope my entire body, which I attribute to the 900 fill goose down. I tried using the draft collar and that worked great too. In fact, I was so warm that it was unnecessary to use the mummy hood at all, and I slept all 3 nights with a light polypro hat on instead. 

After this weekend, I am really looking forward to using my new Western Mountaineering bag on the rest of my Long Trail section hikes this summer and fall. If you are looking at $250 down sleeping bags for 3 season use, I strongly recommend that you consider upgrading to the more expensive Western Mountaineering Ultralite 20.

The Western Mountaineering Ultralite 20 is available in the Sectionhiker.com Gear Shop. Check it out.


Reply to Jason: Here is a photo of the Ultralite that you asked for, to give you an idea how well this bag compresses. I’ve stuffed it into an 8L waterproof stuff sack with room to spare. Yep, I just finished off that Sierra Nevada too.

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