Western Mountaineering UltraLite Review

Performance Comparison

Warmth

The 20° degree Fahrenheit rating of the UltraLite is pretty conservative. It is certainly on the warmer side of the 20°F bags available and is the warmest bag in our review. We slept in a 14F night with long underwear and a light fleece and were super comfortable when the draft collar and hood were properly cinched.


While we appreciate the extra space to roll around in or comfortably throw a thick jacket on while using the bag, which can be found in the The North Face Cats Meow and Kelty Cosmic Down, and to a lesser extent, the Marmot Phase. The UltraLite is a much more thermally efficient sleeping bag for average sized, or still even slightly larger than normal users. Remember that fit is a crucial component of a warm sleeping bag. The wider, "more-comfortable" bags have more dead air space inside the bag, resulting in a better chance for cold spots and the possibility of disrupted sleep.


Similar to the MegaLite, the UltraLite features continuous horizontal baffles. This design allows you to shift down from the top of the bag to the bottom of the bag, or vice versa. This is a very functional way to control the temperature inside your bag; you can have more insulation on the top of the bag for cold nights and the opportunity to shift that down to the bottom, where it can be compressed (and less useful for keeping you warm on those hotter nights).

Weight

The regular length UltraLite weighs 1 lb 13 oz. It's nearly the lightest bag that is rated to a temperature of below 25°F (in our review) and is lighter than a majority of bags rated in the 30-35°F range (that are currently on the market). The exception is the Marmot Phase 20 which isn't quite as warm as the UltraLite but warmer than most other 20° F bags and is more compressible and an amazing 6 ounces lighter checking in at 1 lbs 7 ounces and is one of the better performing all-around bags in our review. Be sure to check out the chart below to compare the weight score of the UltraLite to the other bags in this review.


What's more amazing about the weight of the UltraLite is not only is it warmer than a majority of 20° and 25° bags we reviewed, but in several cases, it was significantly warmer than these models.


The UltraLite uses "Extremelite", a 12D fabric for the shell, and is the exact same as our award winner, the Western Mountaineering MegaLite. Extremelite fabric weighs less than 1 oz per square yard, which is insanely light. The ultra-fine yarn that makes up this fabric is very soft and ultra-compressible. Albeit a little bit fragile, this very down-proof fabric greatly contributes to the bag's low weight and high compressibility. Another contributing factor to the low weight of the UltraLite is its slim cut, which is indeed one of the narrower sleeping bags in our test. Less material obviously shaves a handful of ounces from the overall weight.

Comfort and Fit

High loft and soft, lightweight materials make the UltraLite a very inviting place to lay your head for the night, earning it an 8 out of 10 in this metric. However, the narrow shoulder and hip girth make it less comfortable than the MegaLite or Marmot Phase 20. Folks who mostly sleep on their back won't detect this as much, but for side and tummy sleepers, it is more likely to be noticed. Overall, the UltraLite and MegaLite offered the softest and most comfortable feeling face fabric out of all the bags that we tested. It is worth noting that the Marmot Phase offers slightly larger dimensions and feels slightly wider than the UltraLite.


The Kelty Cosmic Down, Sierra Designs Backcountry Bed 600, and Nemo Salsa 30 are reasonably priced contenders that scored a 9, 10, and 10, respectively, in the comfort metric. If you're looking for an option that offers quality and comfort at a cheaper price point, consider these bags.

Packed Size

Five inches of loft looks like a lot to pack away when this bag is laid out on your sleeping pad. However, the 850+ fill down and extremely lightweight materials make the UltraLite a much smaller package than you would expect, especially when stuffed into its included well-fitting stuff sack - or better yet, a compression sack.



Despite being the warmest bag in our review, it was among the most compressible and packed down WAY smaller than all the 20F bags (and most of the 30F bags). The only bags that packed smaller were the Western Mountaineering MegaLite, Marmot Phase and Sea to Summit Spark Spark III.

Features and Design

The continuous horizontal baffles on the UltraLite make for an easy-to-use thermostat. The down chambers encircle the sleeping bag from zipper to zipper, allowing the user to shift down towards the top of the bag for cold nights. Conversely, you can 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 more or less.


The above chart details each bag's score in the Features and Design metric.


Similar to the AlpinLite, the UltraLite features a reverse differential hood, which is extremely comfortable. This basically means the fabric on the inside of the sleeping bag is actually larger than the shell fabric. This hood covers your head, offering extreme comfort, and is excellent at trapping heat without needing to tighten it too much.


Western Mountaineering uses a one-inch stiffening tape on both sides of the zippers that aids in easy, snag free operation. The draft tube along the zipper, and the draft collar on the UltraLite are lofty; they mate well, which keeps the warm air in, and cold air out. However, Western Mountaineering should consider a different method for closing the draft collar and the hood of this sleeping bag. Both closures are small pieces of velcro that are hard to spot and operate and come open very easily in the night. The draft collar, in particular, allows a minimal amount of cold air to enter the bag.

Versatility

The UltraLite is likely the most versatile bag in our review. It's capable of unzipping for warmer nights, but can be used in temperatures of 20F, as rated (and when sealed up). For sleepers that experience the cold sooner than others, or on extra cold nights, nearly all of our testers had no problem adding at least one lighter weight jacket to boost this bag's warmth (if temps really got frigid). The continuous baffle design also lets the user further regulate temperature. The bottom line is even for the weight-conscious backpacker, this one pound thirteen ounce sleeping bag is very reasonable to carry and is certainly warm enough for the cold nights of the shoulder seasons or at higher elevations.


The North Face Cats Meow and Nemo Salsa 30 are two contenders that also scored 10 out of 10s for versatility. The Cats Meow excels on shorter backpacking trips, extended car camping trips, or adventures where you might expect to feel a bit of moisture. The Salsa works for those fast and light backpacking trips, but is also comfortable enough to be used on extended car camping trips, especially as it ensures that the sleeper has adequate space to move around in.

Best Application

The UltraLite is the one of the best sleeping bags in our review for 3-season use. Because it's so warm, it's best suited for travel in the mid to high elevations in the middle of the summer. It is also warm enough to stretch your season into the shorter days of fall and transitional periods in the spring. If you're someone who gets cold easily, the UltraLite could be your anytime, anywhere 3-season bag. It's plenty warm for most summer-time mountaineering in the lower-48 and lower regions of Canada and is light and compact enough for spring multi-day ski touring missions.

Value

One of the reasons that we prefer high-quality down sleeping bags is that they have a very long lifespan if they are well taken care of. Unlike synthetic fabrics, they can be stuffed and unstuffed over and over without breaking down the insulation. If you are able to buy a quality bag that can handle most, if not all, of your on trail (or off trail) adventures, you will save some cash in the long run.

However, at around $500 for the regular length model, the UltraLite is a pretty big investment. But, if that bag can sustain 10-20+ years of use, and be your go-to for most of your backpacking trips, along with maybe the occasional mountaineering or ski touring adventure, we think that it is a good investment. You won't be disappointed by the UltraLite. If considering the Ultralite be sure to check out the similarly performing Marmot Phase 20 which is $40 less expensive.

Bottom Line

The UltraLite is a former Editors' Choice and remains a fantastic bag. It offers a few disadvantages, mostly revolving its slimmer-than-average fit, but is among the lightest, warmest, and most compressible bags for its temperature rating, similar to the Marmot Phase. The UltraLite wins our Top Pick for the Best 3-season sleeping bag for cold sleepers or "colder" 3-season use, as it is still noticeably warmer than the Phase. The MegaLite won our Editors' Choice over the UltraLite because it is a little more spacious; it also offers a 30°F rating that we think is warm enough and more appealing for most folks that are interested in backpacking bags. As a result of having less insulation, the MegaLite compresses smaller and is five ounces lighter. If you're a cold sleeper, the UltraLite is tough to beat for weight, packed size, comfort of materials, and warmth.