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Kelty Cosmic 20 Degree Down Sleeping Bag Review

I bought the Kelty Cosmic 20 degree down sleeping bag on Amazon to use for hiking, travel, and bicycle touring. I needed a bag that was light enough for backpacking, warm enough for 3 season use, and, most importantly, affordable. After extensive research, I settled on the Kelty Cosmic 20. In my opinion, this is the best value lightweight down sleeping bag on the market.

My Kelty Cosmic 20 Sleeping Bag
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Main Features of the Kelty Cosmic 20

  • Available in 3 sizes- Fits people up to 6’6”
  • 19 degree EN rating- This is a lower limit rating
  • 18.2 oz of 600 fill dridown- Treated for water resistance
  • 60 inch zipper- For easy entry and exit
  • 20D Nylon taffeta shell with a 50D Polyester taffeta liner- These are down proof and durable fabrics.
  • PFC free DWR down and fabric- This means that the bag is treated for water resistance without the use of PFCs. This is better for the environment and possibly your health.
  • Built-in draft collar and hood- To keep drafts out and to keep your head warm
  • Affordable price- One of the best value sleeping bags on the market
  • Included stuff sack- For storage

Warmth and Performance

The Kelty Cosmic 20 has an EN comfort rating of 19° or -7 Celsius. It uses 18.2 ounces of 600 fill DriDown for insulation.

Before taking a new piece of gear out camping, I like to test it out in my back yard first to make sure it works as it’s supposed to. This is particularly important for sleeping bags. I don’t usually camp in cold weather but I did test the bag over the winter to see how it would perform. Keep in mind, I’m an average sleeper (not cold or hot).

When the weather fell to the mid-20s last January, I set up camp in my backyard. I slept in my Big Agnes 1 person tent on top of a CCF pad and inflatable for extra insulation from the snow. I spent the night in the bag while wearing a wool base layer. At that temperature, the bag kept me surprisingly warm. While I wasn’t toasty, I was definitely warm enough to get a decent night of sleep.

I wrapped the draft collar around my neck and tightened the cinch on the hood. This kept the warm air inside the bag. While reading reviews before purchasing, I read one complaint about cold spots. I did not notice any. My bag lofts surprisingly well.

Kelty Cosmic 20 loft
A view of the loft

While camping in 20 degree weather, I’d probably want to wear my down puffer or fleece to sleep. Having said this, the bag is perfectly usable in 20 degree weather. The 20 degree rating is a lower limit, after all. That means that the bag is designed to keep you alive at that temperature.

I’d say this bag is comfortable down to around freezing. At that temperature, I could probably sleep in just a t-shirt and shorts if I wanted to.

A Note about DriDown

The biggest problem with down sleeping bags is the fact that down loses its insulation qualities when it gets wet. The Kelty Cosmic 20 uses 600 Fill DriDown for insulation. DriDown is natural down that has been treated with a special polymer. This creates a hydrophobic coating on the down without adding much weight. DriDown offers several benefits over untreated down including:

  • Faster drying- Takes 33% less time to dry than untreated down.
  • Lofts better in moist and humid conditions- DriDown retains some lofting abilities even when it’s damp.
  • Stays dry better- They hydrophobic treatment helps keep your bag dry longer.
Down feathers
Down feathers

This feature comes in handy even if your shelter is completely waterproof. Under the wrong conditions, humidity and condensation can build up in your tent to a point that your sleeping bag gets soggy. Traditional down would lose its loft in this case and you would get cold. Condensation is particularly problematic if you camp in a bivy sack.


For its weight, the Kelty Cosmic 20 is surprisingly light at just 2 pounds 6.6 ounces (1.093 kilos) for the regular version. 18.2 ounces (516 grams) of that weight is the down filling. While I wouldn’t consider this ultralight, it’s definitely lightweight. Particularly when compared to low-end synthetic sleeping bags you might find at a big box store like Walmart. The Kelty Cosmic 20 is definitely light enough to use for backpacking.

While this bag light for the price range, it’s heavy when compared to ultralight options from cottage manufacturers. For example, a high-end ultralight 20 degree sleeping bag like the Feathered Friends Hummingbird weighs around 1 pound 8 ounces. Of course, the bag costs over $500. You can cut a few ounces more by switching to a camping quilt. The Enlightened Equipment Enigma weighs just over a pound at 19.25 ounces for the regular size 950 fill version. Of course, this bag costs hundreds more than the Kelty.

This gives you an idea of the weight you could save if you’re willing to shell out a couple of hundred extra bucks. Are high-end bags worth the additional cost? That’s for you to decide. If you’re on a tight budget, the Kelty Cosmic 20 offers one of the best price to warmth ratios. If you’re looking for an ultralight bag, you can save over a pound by saving up for a higher-end option.

Packed Size

In a compression sack, the Kelty Cosmic 20 packs down to a volume of 8.7 liters. That’s about twice as large as some high end 20 degree sleeping bags. By comparison, it’s a pretty bulky bag.

However, when compared to lower-end synthetic sleeping bags, the Kelty Cosmic 20 packs significantly smaller. For example, an average big box store 20 degree bags only pack down to around 12 liters. Even though it’s not the most compact sleeping bag, the Kelty is easily small enough to use for backpacking.

One complaint that I have is the fact that the Cosmic 20 does not include a compression sack. It doesn’t include a large storage sack for storing the bag uncompressed when not in use either. It just includes a large stuff sack. Personally, I’d rather pay a few bucks more to have a compression sack included instead of a stuff sack.

To save some space in my pack, I bought a compression dry sack. I went with a 14 liter model so I can store a few extra items with it. You could also use a 10 liter compression sack. 

To be honest, packed size is one area where I am a bit disappointed with the Cosmic 20. It is bulkier than I expected. While traveling, I always pack camping gear. I usually carry my 44 liter Osprey Talon hiking backpack which passes for carry-on size. This sleeping bag takes up about 1/5 of the volume of my bag. This doesn’t leave me enough space for the remainder of my gear for some trips. In those cases, I pack my 60 liter backpack instead and check it. For ultra-compact travelers, this bag isn’t ideal.

For bicycle touring and hiking, the extra volume doesn’t really matter. I can strap gear onto the outside of my backpack or bikepacking bags to make enough space inside.


The Cosmic 20 uses a 20D Nylon taffeta shell with a 50D Polyester taffeta liner. These materials are thicker than those you would find on a higher-end sleeping bag. A positive of a higher denier fabric is the fact that it makes the bag more durable. With a thicker fabric, you don’t have to worry as much about rips and tears.

The drawback to the thicker fabric is the fact that it’s just not as soft to the touch. These higher denier fabrics are a bit stiffer. They don’t have that silky smooth feel that higher-end fabrics offer. They also add to the weight and bulk of the bag.

Personally, I find the 20 denier inner shell to be plenty soft. I would appreciate the lighter weight and reduced bulk of a thinner fabric. Of course, Kelty had to cut costs somewhere while making this budget sleeping bag. Using a cheaper, thicker fabric was one way to do that.

The hood and draft collar of the Kelty Cosmic 20
The Kelty has a great hood and draft collar

Size-wise, the bag is surprisingly spacious. Being 6’1” I went with the long size to give myself a bit more legroom. The 64 inch shoulder is on the wider side for sleeping bags. This bag offers enough space for me to comfortable toss and turn in my sleep as much as I need to. It’s pretty roomy for a mummy-style sleeping bag.

One feature that I really like is the hood. It lofts really well. Being a bald guy, my head gets cold easily. When I cinch up the hood there aren’t any drafts and my head stays warm. I don’t even need to wear a hat.

The Zipper

The ¾ length zipper makes getting in and out of the bag easy. The fabric around the zipper is fairly stiff due to the higher denier. This makes it less likely to get caught up while zipping and unzipping.

One minor complaint is that the zipper is not full length. I prefer sleeping bags that have zippers that go all the way to the bottom. This comes in handy during warm nights because it allows you to use the bag like a quilt.


Kelty has a great reputation in the outdoor equipment market. They make high-quality gear in the mid to high-end price range. So far, this bag has proven to be pretty durable. I haven’t experienced any issues with the fabric, zipper, or down insulation. Mine still looks like new.

Having said this, while researching this bag before making the purchase, I read several reports of zipper problems including broken zippers. So far, the zipper on my bag has performed just fine. It feels sturdy and zips perfectly smoothly. No complaints here. I’ll report back if I have any issues down the line.

Best Application for the Kelty Cosmic 20

This is a ‘do it all, master of none’ kind of sleeping bag. It’s not the cheapest, lightest, or most compact bag on the market. It doesn’t perform the best in any one category, but it does well in all.

This bag works great for 3 season backpacking, bicycle touring or bikepacking, or international travel. It’s light and compact enough to fit in most backpacks. It’s warm enough for cold shoulder season use. So far it has proven to be pretty durable.

a fully loaded hiking backpack

Where this Bag Falls Short

Because it is a down bag, it won’t perform well when wet. Down clumps and doesn’t loft when it makes contact with water or humidity. Even with the DriDown treatment. If you plan to camp in particularly rainy or humid regions, consider purchasing a fully synthetic sleeping bag. Be sure to keep condensation in mind as well.

While 20 degrees is pushing the limits for this bag, it is usable at that temperature if you sleep in your jacket and long pants. The bag will keep you more comfortable in 25-30 degree weather. For winter camping, where you expect temperatures to drop very far below freezing, this bag isn’t ideal. In that case, I’d look for something a bit warmer.

Personally, my biggest complaint with the Kelty Cosmic 20 packed size. It’s just a bit bulkier than I would have liked.

Who is the Kelty Cosmic 20 For?

This is a budget down sleeping bag that is light enough and packs small enough to use for backpacking. It is warm enough for 3 season use as well.

When you choose this bag, you are making a compromise. You’re deciding to carry about 1 extra pound of weight use up about 2-3 liters of additional volume in your pack to save a couple of hundred dollars. In my case, the money savings was worth it.

Camping gear offers the best value in the mid-range. That’s what this bag is. When you buy a $500 sleeping bag, you’re not necessarily getting a warmer or more durable bag. You’re paying for lighter weight materials, more high tech materials.

If you can afford to spend a few hundred extra dollars on your sleeping bag, I feel that the reduced weight and bulk that high-end bags offer is worth the money. After all, this is a piece of gear that you will get many years of use out of. Many campers consider the sleeping bag to be their most important piece of gear. I tend to agree. Having said this, the Kelty Cosmic 20 preforms beautifully for its price range.


Dollar for dollar, the Cosmic 20 is probably the best value sleeping bag on the market. It is a legitimate 3 season backpacking bag from a name brand manufacturer. It packs down relatively small and is light enough to carry in your backpack.

Sure it weighs a bit more and is a bit bulkier than higher-end offerings. For the price, that’s to be expected. Kelty had to make sacrifices somewhere in order to stick to this price range.

With the hundreds of dollars that you save when choosing this bag over the higher-priced options, you can cut weight and bulk somewhere else in your backpacking kit.

My Experience with the Kelty Cosmic 20

The first real use I got out of this bag was during a short bicycle tour this spring. My old sleeping bag was a bulky synthetic 40 degree summer bag. Last season, it just wasn’t keeping me warm enough so I decided to retire it.

Compared to my old bag, the Kelty is softer, roomier, and most importantly, much warmer. Temperatures dropped to the mid-40s during the night and I was toasty warm. I even unzipped the bag at times to shed some heat.

The same time last season while sleeping in my old bag, I had to bundle up in my jacket and warm pants to keep myself warm. Even then I was so cold I could hardly sleep in 45 degree weather. The Kelty is a major improvement. I expect the down to last longer as well. It doesn’t seem to degrade as rapidly as synthetics. I hope to get years of use out of this bag.

Wild camping with my Kelty Cosmic 20 during a bicycle tour

Final Thoughts on the Kelty Cosmic 20

Ultralight camping gear is incredibly expensive. Not everyone can afford to spend over $1000 on a sleeping bag, backpack, and tent. Luckily, mid-range options are available which are nearly as good.

Before purchasing this bag, I researched extensively. I spent hours learning about backpacking sleeping bags. I looked into the offerings from name brands and cottage manufacturers. For a while, I even looked into sewing my own sleeping bag.

In the end, I found the Kelty Cosmic 20 to be the best choice in my budget range. To me, it just wasn’t worth spending an extra $200 to cut a pound from my pack. I could cut weight elsewhere for less money.

If you can afford a high-end sleeping bag, I think it’s worth the extra money. If you’re on a budget like I am, the Kelty Cosmic 20 is probably your best option.

You can buy the Kelty Cosmic 20 on Amazon here.

Do you have a Kelty Cosmic 20? Share your opinion about the bag in the comments below!

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Disclosure: Please note that some of the links in this post are affiliate links, including links from the Amazon Serivices LLC Associates Program. At no additional cost to you, I earn a commission if you make a purchase through these links. I only recommend products and services that I use and know. Thank you for reading!