What we like: A super comfortable and fully featured option for two campers; temperature rating feels generous. This zipper is the entire length of the bag and built for use. Large pull tabs help to locate it in the night, but it is a little more delicate than we’d prefer. It’s especially important to know them for those who don’t have so much experience in tourism. Let’s try to figure it out with specific examples and take a few sipid models: Kelty Cosmic down 20, Marmot Trestles 30, The North Face Women’s Cat’s Meow 20 and Klymit KSB 20. These sleeping bags are roughly the same class, so the comparison will be correct. To understand the variety of models, you need to distinguish a few basic principles. Purpose of the sleeping bag The two pads I used for testing were the Thermarest Women's Trail Pro (R-5.1) & Exped DownMat 9 (R-8). The R-8 pad, sufficient for subzero *F temperatures, was the pad I used on the cold-sleeping night in the teens. It was clear that all variables were unchanged except for the daytime/nighttime temperature swing. As a brand, Kelty is also strong on sustainability. It is one of the four founding members of The Conservation Alliance. The Alliance was founded in 1989 by industry leaders REI, Patagonia, The North Face, and Kelty, who shared the goal of increasing outdoor industry support for conservation efforts.

The 600-fill of hydrophobic down is wrapped in a durable 50D polyester taffeta liner and a ripstop shell, all of which is shaped into a mummy-style bag that hugs your body in the right places. Features such as the adjustable hood, draft collar, and draft tube work well to hold in your warmth. Clouds? They just don’t come close. I was warm throughout the night, and the DriDown kept the moisture at bay. Keep in mind, my coldest tests were in the mid 30s and I didn’t have to pull out the super warm layers. That said, the 20 degree rating on the Cosmic Down 20 may be a bit of a stretch. Although a sleeping bag’s warmth is usually quantified by the EN rating mentioned above, the fill power and loft are the two most important factors in determining what that rating will be. What we don’t: Heavier and less compressible than mummy bags (although it’s a nice improvement from the past model).

Performance Comparison

Now, I dont come across many perfect things in my life and this is not one of them. It has some slight, VERY slight issues that MAY bother others: the zipper tends to be a little annoying when zipped down all the way, it's a little annoying (not hard) to get it zipping again, but once it's started it's great (simple solution: just don't unzip it ALL THE WAY... problem solved). Second thing that may bother someone (this is also my first mummy style bag so I'm not sure if most are like this) is that the hood doesn't cinch tight around your face unless you have a giant head (could be a perfect fit for my girlfriend) HOWEVER, this is far from a deal breaker.

Update: The Kelty Cosmic Down 20 is a staple, and doesn’t change that often. Kelty updated it in 2016, and the bag is not received a major revision in 2019. Kelty Cosmic Down 20 Video Review Compared to its 20-degree competitors, it measures up favorably, with models like the synthetic The North Face Wasatch 20° Sleeping Bagweighing in at 3 pounds and the down-filled Marmot Ironwood20 at 2 lbs 6.7 ounces. Synthetic—Usually slightly heavier and less compressible than down fills but, in its favor, costs a lot less and can insulate even when damp or wetWater-resistant down sleeping bags are becoming ever more common on the market. This one, however, does something that the vast majority of its water-resistant competitors don’t—it’s affordable. Compared to other 20-degree-rated sleeping bags with water-resistant down fills, this bag could easily be classified as a “budget” model and is one of the cheapest in its class out there. Shell Fabric The material used in your sleeping bag’s shell or outer layer is important for two reasons: protection and durability; and, resistance to dampness and condensation. 1) Protection and durability There’s no definitive answer to this one, and in most cases, the weight of your future sleeping bag will be determined by finding the ideal weight-to-warmth ratio, basing your calculations on how heavy a bag you’re willing to carry and how much warmth you will need to sleep soundly and safely where (and when) you intend to do your camping.

The Lower Limit means this bag will technically be comfortable to 19 degrees. However, through our tests “comfortable” isn’t really the word. Survivable is the word. This is a common issue with sleeping bags and the EN testing system, and we feel the rating should be higher. More on sleeping bag EN testing in our guide.

Get Schooled in the Geometry of Comfort

If you know you "sleep cold" or have plans for colder trips in the spring or fall, the Western Mountaineering UltraLite is the bag for you. With 17 ounces of 850+ fill power down and a legit draft collar, this is the warmest bag in our test. Our cold-sleeping lead tester used it at 12,000 feet in October and had no problems staying warm. At the same time, its full-length zipper and horizontal baffle construction provide ample options to shed heat and cool off on warmer nights. We slept comfortably in this bag across an expansive range of overnight temperatures from 10° to 55°F.