Reviews You Can Rely On

Big Agnes Crosho UL -20 Review

This bag has 35oz of high quality down with a scant 11oz for the materials weight
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Big Agnes Crosho UL -20 Review
Credit: Big Agnes
Price:  $600 List
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Manufacturer:   Big Agnes
By Matt Bento ⋅ Review Editor  ⋅  Dec 18, 2018
  • Warmth - 20% 9.0
  • Weight - 20% 8.0
  • Comfort - 20% 6.0
  • Packed Size - 15% 8.0
  • Features - 10% 6.0
  • Weather Resistance - 15% 9.0

Our Verdict

Big Agnes discontinued the Crosho UL -20 in 2020.
Superior warmth-to-weight ratio
Tight fit for bigger sleepers

The Big Agnes Crosho -20 has one the best warmth-to-weight ratios we've ever seen. Big Agnes is known for their emphasis on comfort and making sure you get a good night sleep in their roomy bags that couple with their sleeping pads, at the expense of weight savings. With the Crosho, they've successfully created a great bag for the alpine climbing and cold weather backpacking crowds. We weren't able to test this bag to it's lowest temperature limit (-20F), but compared to other bags in our review with a -20 rating, it doesn't feel as warm. That being said, if this bag had a 0 or even a 5-degree rating, we would still be impressed with the Crosho's lightweight performance.

This bag reminds us a lot of the classic Feathered Friends Snow Bunting, an awesome bag for alpine climbing. Both the Snowbunting and the Crosho have a narrow cut to keep the weight down and boost thermal efficiency, making them excellent for folks on the move, but not as comfortable as wider bags with more space to toss and turn. The Crosho saves a few ounces with a half-length zipper, but this makes it less versatile since there is less venting for times when you've overestimated the cold, or you need to make one bag work for two-person shiver bivvies.

Our Analysis and Test Results

Performance Comparison

big agnes crosho ul -20 - with 35oz of 850 fill power down, this is one of the warmer bags we...
With 35oz of 850 fill power down, this is one of the warmer bags we reviewed.
Credit: Matt Bento


  • 20F is a temperature our testers rarely encounter in the Eastern Sierra, especially in these warmer, modern times. Two other bags in our review, the North Face Inferno -20 and the Marmot Col -20, feel warmer to our testers than the Crosho. A look at the numbers supports this feeling, sort of. The Inferno has 36.4oz of 800 fill down, while the Crosho has 35oz of 850 fill down. That's pretty dang close, and it's hard to assert that one bag is warmer than the other based off this. The Marmot Col -20 has a whopping 44oz of 800 fill down, so it makes sense that our testers think the Col is warmer.

Sometimes we wish companies wouldn't rate their bags, since, despite EN ratings and high tech heat sensors, warmth and comfort is so subjective. So we're not saying that -20 is a bogus rating, we're just stating that it doesn't seem as warm as the other bags we reviewed with the same temperature range. Regardless of what number is in its name, the Crosho is an exceptionally warm bag for its weight. It's much warmer than the Rab Neutrino 800, the Nemo Sonic and the Western Mountaineering Antelope.

big agnes crosho ul -20 - our 6' tall 200lb tester felt that this bag felt too tight. it's...
Our 6' tall 200lb tester felt that this bag felt too tight. It's also available in a larger size.
Credit: Matt Bento


According to our scales, his bag weighs 46oz, with a fill weight of 35oz, with the remaining 11oz for the zipper, drawstring, and all the shell fabric. This gives the Crosho an impressive warmth-to-weight ratio, one of the best we've seen. This bag is at least as warm as the Editor's Choice Award-Winning Western Mountaineering Kodiak MF and the Feathered Friends Snowbunting. Looking to turn the thermostat down a notch and carry a lighter bag? Check out the Western Mountaineering Antelope MF.

big agnes crosho ul -20 - this sleeping bag weighs 46oz after subtracting the weight of our...
This sleeping bag weighs 46oz after subtracting the weight of our compression sack.
Credit: Matt Bento


For a minimalist, lightweight bag, the Crosho is pretty comfortable. Its measurements are very similar to the Snowbunting, with 60" of shoulder girth, 54" in the hips, and a narrow 36" in the foot box. Compared to bags with a wider cut like the Western Mountaineering Kodiak MF and the Nemo Sonic, the Crosho feels constrictive. If you're going out for weeks at a time, it's nice to have extra room in your bag to burrow, read, and toss and turn. The half-length zipper makes it impossible to vent the bag down by your feet or completely open up the bag and use it as a blanket. To be fair, the Crosho is not a blanket. Its a sleeping bag designed to keep you alive and warm in the mountains.

big agnes crosho ul -20 - the hood employs one effective cinch cord, we just wish we could...
The hood employs one effective cinch cord, we just wish we could tighten it from the inside of the bag.
Credit: Matt Bento

Packed Size

The stuff sack that's included with this bag isn't very small, but we had no trouble cramming the Crosho into the compression sack we used for the lighter Western Mountaineering Versalight 10 and the super room Kodiak. 850 fill down is very compressible and re-lofts quickly after it's unpacked. The storage sack that comes with this bag is a little too small for storing the bag full lofted, and we'd suggest finding a bigger sack or hanging the bag for storage.

big agnes crosho ul -20 - this bag packs down relatively small for its warmth.
This bag packs down relatively small for its warmth.
Credit: Matt Bento

Weather Resistance

The DWR-treated shell fabric on this bag has no trouble repelling light rain and snow, and is seemingly impervious to frost and dew. After the shell, there's still several inches of hydrophobic Downtech treated goose feathers between the sleeper and the elements. This bag isn't as weather resistant as the Marmot Col -20, but it's way lighter, and you won't need a completely waterproof sleeping bag if you're carrying a tent, tarp shelter, or a bivy sack.

big agnes crosho ul -20 - light rain is no problem thanks to the dwr treated shell fabric.
Light rain is no problem thanks to the DWR treated shell fabric.
Credit: Matt Bento


This bag stays lightweight by not going heavy on the features. It only has a half-length zipper, and one simple drawstring to secure the hood around the face. When pulled tight, the hood creates a nice air slot for your nose and mouth, with a draft collar to keep out the cold air. Our testers wish the cinch cord was situated on the inside of the bag instead of the outside. The draft tubes on either side of the zipper aren't as insanely lofty as draft tubes on the Western Mountaineering bags, but we still didn't notice any cold air seeping in around the zippers.

big agnes crosho ul -20 - this bag is one of the only models we reviewed with vertical...
This bag is one of the only models we reviewed with vertical baffles. Its draft collar is effective at keeping out cold air, and the zipper operates snag free.
Credit: Matt Bento

Best Applications

When “the woods are lovely, dark, and deep” and you've miles to go before you sleep, you need a lightweight sleeping bag. Frost was on a horse in the poem, so he'd likely go with a heavier, warmer bag like the Marmot Col -20, but for human-powered winter travel, your knees are going to love you for carrying a sub-three pound bag. The Crosho is geared for long winter hikes in the great north woods and alpine missions where compressibility and lightweight are crucial.


This bag costs $579 for the regular sized version of the bag. While that may sound expensive, it's less than the Western Mountaineering Kodiak and the Feathered Friends Snow Bunting. It's around the same price as the less warm Rab Neutrino 800. Regarding high quality down for your dollar, it's not a bad deal at all.

big agnes crosho ul -20 - a half zipper detracts from this bag's versatility since you can't...
A half zipper detracts from this bag's versatility since you can't vent your legs on warmer days. Fortunately, this day was not warm.
Credit: Matt Bento


The Crosho is a great alpine bag, earning top marks in warmth, weight, and compressibility. While it's not as comfortable as our Editor's Choice Award winner, it's slimmed down and ready for high mountains and long treks, and will save you about $100. If you're on the slender side, the Crosho could be the perfect bag for your adventures this winter.

Matt Bento