Big Agnes  Sidewinder SL 20 Sleeping Bag

I've had this bag for about 2 months now. I slept with it in 28 degree weather in Colorado while it was pouring rain outside my tent, and I was 100% warm. I slept on a yoga mat. If you plan on sleeping outside a tent while the weather is in the 20s, you'll want a liner, an additional trail quilt and/or a heavier sleeping bag. I'm 6' tall. I bought the long. The reason I bought this bag is because I valued compression size over weight. I have a 37 liter pack so I needed a bag that would save space. After sleeping out for 7+ nights, I can happily say that I made a smart decision with this purchase. You can sleep on your back with this bag. I do it all the time in a hammock.

1st off this is a cold 20deg bag feels more like a 30deg in the field. But that us not it's worst offense. This thing leaks down like a sieve! If you sleep on your side you tend to move around a lot after a recent 4 day trip my tent floor looked like an Audubon murder scene each morning and it isn't leaking out of just the seams but the fabric itself. The zipper catches all the time and the shoulders are very narrow which makes rolling around even more difficult. I think that the variable padding design is good in concept but my hips were still complaining the next morning. I wanted this to work but it just doesn't. Makes me wonder if the folks who recently gave it an award actually slept in it...

I have a collection of sleeping bags at this point, and this is by far the most comfortable I've used. Having the zipper in the middle is really a game changer for side sleepers. Plus this bag is quite roomy, feels like you're under a blanket. The only negatives are that it sheds a lot, I mean A LOT. Everything was covered in feathers after a night in this, looked like a goose massacre took place. The other negative is that this bag is not very compact. I ended up buying a 15L compression sack, but even with that its still quite large. So something to consider if you plan on using this for backpacking. Personally though, that extra weight and space is worth the comfort this bag provides.

Just used this bag this weekend near Sierraville CA. Im 5'8", 195lb. I went with the mens version as it was the only one in the store and I decided I wanted the extra room. This bag lets me stretch a lil more and was still warm enough. Granted the weather was warmer, but being roomier gives me more space to add layers. There was a good amount of feathers that came out after some tossin and turning in my sleep. However it's a factor I'm willing to deal with since I got to do my normal sleep and was not woken up due to restrictive movement like in my other sleeping bags.

This sleeping bag is so comfortable and warm. I just spent four nights in a row sleeping in this bag, and it was the best camping sleep I’ve ever gotten! I am a side sleeper and mummy bags gave me hip pain, so I did quite a bit of research and settled on the sidewinder. This bag allows me to sleep with my knees and feet in a variety of positions. I am a 5’10 woman, but this bag fits me perfectly!

This is my second one. The first one I used on my through hike of the Appalachian trail in 2022. It performed well in all temperatures. I used it the entire trip. On the coldest nights it kept me warm on the hottest nights I used it as a quilt. I destroyed it by not heeding the washing instructions and wash it with normal detergent. The down clumped together and I couldn’t get it to separate. The insulation was destroyed.

So I have slept in this for 3 nights on one trip so far. The center zipper is more convenient than a standard one-side only zipper, but I still find myself rotating inside the bag so that it is not permanently stomach centered. That is my issue as I can't wear with the hood as I need to stick my arm out to the side due to shoulder issues. I can't exactly figure out how to use the arm hole pocket feature yet. Regardless, this bag was definitely warmer than my old bag that was similarly rated. Will likely open up the zipper a bit near the feet next time. I like that it comes with both a loose storage bag AND a small compressed bag.

Best sleeping bag I’ve ever used. Great for a side sleeper such as myself. I’ve never been able to sleep on my back like a mummy except for a few minutes here and there. This is the bag you have been looking for, fellow side sleepers.

I'm 6'4" and usually a regular size bag works for me; and when I'm at home I'm a side sleeper so tried the regular size initially. The regular size ended up being too small for my side sleeping position because of how I pointed my toes and bent my knees so I exchanged it for the long size. Now it fits perfectly and is super comfy and warm! If you're on the fence about sizing up I'd definitely recommend it.

Reviewer: cold-sleeper, side sleeper. Base layer pants, shirt, Merino wool socks Conditions: February, Dry night, 15-20mph gusting winds, 28deg., open air tarp shelter. Weight as used: 1128grams (2lbs 8oz. exactly as advertised) I was very pleasantly surprised at the warmth and fit of this bag. I've had several bags before that were "cut for side sleepers" and for this cut they were often too roomy and I was chilly in them. I feel that this bag got the fit just right and the insulation management dialed in for comfortable sleeping and heat retention. Looking through the bag in the morning sun I was able see a silhouette and uniform distribution of the insulating material. In my last 2 test bags I was able to easily see where the down was (dark spots) and WASN'T (lots of very light spots). In THIS bag, it was clearly a uniform distribution with lightly shaded insulation throughout each baffle and no major cold spots. The foot box was roomy as well and the FireLine material (never heard of it before) seemed to reduce those cold shocks you find as you kick around. The baffle along the zipper also worked well to keep out any drafts; I felt no leaks there. But that's where the baffle's useful ends. The zipper-and-baffle do NOT play well together! This is a snag-ful zipper, NOT snag-free. Overall the bag was comfortable and work, while all this is well and good, there is this HUGE caveat of snagging the zipper at nearly every opportunity. The baffle material is easily caught in the zipper from knee to nose at least 10-12 times getting in the bag and getting out. Other reviewers across the internet have said the same thing and I fully agree with them; this zipper or the baffle or both are TERRIBLE. Ultimately I believe it's a baffle fill issue: either too much material for the amount of fill, or not enough fill to keep the material out of the zipper path. The open/close issue would be enough to get rid of ANY other bag, but this bag is so dang warm and roomy - I'm not sure I'll be returning it. If Big Agnes reads these, you've got a good design with 2 small changes: (1) bump to 850FP (2) draft tube change - either more fill or less material. The problem is that the draft tube material gets caught in the zipper and needs to loft more to avoid bunching up and snagging. Final point: If you can deal with a snagging zipper (A LOT) because you're looking for a sub $300 bag with below average weight and above average warmth for a side sleeper - this is pretty dang good option. Just don't say I didn't warn you about the zipper.