Kelty Cosmic 0 Review

Cosmic Down 0 Updates

Kelty has updated their Cosmic line since our test cycle with this winter bag. The new model was revised with trapezoidal baffles, and the water-repellent coating is now PFC-free. The fill weight has increased by 6 oz, so it's a little warmer than the previous iteration. Most importantly, the weight (now over 4.5 pounds for size Regular), packed size, and price have increased significantly. It's now a very large sleeping bag that is unlikely to fit in many backpacking packs. Compare the two versions below; the model we tested is pictured first, followed by the updated Cosmic Down 0.

We have had our hands on the newer version, though, and can confirm that it's heavier and bulkier than ever. We're linking to the updated version above, but the content of this review from here on refers to that older version.

Hands-On Review of the Cosmic Down 0

There's no getting around it—this bag comes in at the bottom of the heap in nearly every one of our testing metrics. If the high price of premium down feathers is stopping you from enjoying cold weather camping, the Cosmic Down provides the necessary warmth but is a bear to carry around in the backcountry.

Warmth

With 33 oz of 600 fill power duck down, the Cosmic Down is as warm as the super-lightweight Western Mountaineering Versalite, which costs hundreds of dollars more and is almost two pounds lighter. A draft collar and an effective draft tube help trap in heat, and so does the narrow foot box.

While not as comfortable for tossing and turning or stomach sleeping, a narrow cut reduces the bag's uninsulated space, keeping the user warmer. While this bag's shell fabric compromises weather resistance, and low fill power down adversely affects packability, warmth is one metric where this budget-friendly bag still does ok.

Weight

At 3.8 lbs, the Cosmic 0 is one of the heaviest bags in our review. This is because of the relatively heavy shell materials and the 33 ounces of duck down needed to achieve the same warmth as lighter bags with higher quality down.

While thick and durable, the 50-denier ripstop shell adds lots of weight. The fill weight to material weight ratio on this bag is about 1:1, where on the Western Mountaineering Versalite, it's 3:1. This bag has a relatively poor warmth to weight ratio and wouldn't be our first choice to lug into the mountains, but it's still lighter than many of the synthetic options out there. If you aren't hiking far, this Best Buy on a Tight Budget could be the ticket, especially if you're looking to save some Benjamins.

Comfort

A generous 62" of girth around the shoulders make it possible for back and side sleepers to snuggle in comfortably. The foot box is on the narrow side at 40", which helps maintain heat efficiently, but doesn't allow for much space to spread your feet around.

We feel that staying warm in bitterly cold winter conditions affects our comfort level more than room to spread out. But if you think you'll be spending hundreds of hours inside a sleeping bag this winter, you'll want something more spacious.

Packed Size

The 600 fill down is the least compressible fill material in our selection, but the Cosmic 0 packs down smaller than the warmest bags in our review, which contain more much more down and have roomier cuts.

The included stuff sack is enormous, but our testers managed to cram the Cosmic 0 down to a backpackable size with a compression sack. If you're primarily looking for a sleeping bag for car camping or short backpacking trips, packed size is less of a concern.

Features

The Cosmic 0 offers many features similar to bags two and three times its price. It has a full-length draft tube that hangs down over the zipper and keeps out wind and moisture. When fully zipped, the draft collar rests under the chin, but it doesn't have a cinch-cord. The hood is well insulated and kept our testers' heads toasty.

We feel that deeper hoods are generally more comfortable, as they aren't as claustrophobic feeling and it's easier to cover our faces when it's super cold out completely. The Cosmic 0 has four webbing loops intended to create a way to attach a sleeping bag using cordage (user provided). Our testers had various opinions on this feature.

Some thought that the tie-in points were helpful for staying on the pad all night, others felt they were unnecessary and inhibited them from sitting up in the bag to drink coffee or investigate curious nighttime sounds. Our lead tester accidentally got one of the loops caught in the zipper and almost ripped it off. Overall, we felt that this bag has one of the more “snaggy” zippers in our review selection. The Cosmic does not have a stash pocket, but the stuff sack will do the trick if you need to keep small items like batteries warm and contained inside the bag.

Weather Resistance

This bag scored low in this metric because it wetted out through the stitching in our light rain test, and it was the only bag in our review that had this problem. It also absorbed the most water in our submersion test and took the longest to dry. Unlike many of its competitors, this bag doesn't have a DWR treatment on its shell fabric. The good news is that you probably won't be using your 0-degree bag in a rainstorm, and weather resistance is the least of your concerns if your sleeping bag is submerged underwater. You can always add a DWR treatment to your bag after purchase pretty easily (we like Nikwax products for this purpose).

Nonetheless, these tests illustrate that the Cosmic is more vulnerable to melting snow and condensation than the other bags. This problem can be alleviated by an adequate tent or bivy sack.

Value

The Cosmic 0 will keep you warm in the low temps for a low price. For folks that only spend a few nights a year in the wintry backcountry, the cash savings are worth the extra weight. For what it is, it's an okay deal.

Conclusion