Zpacks Mummy Sleeping Bag Review

Not sold on quilts but don’t want to compromise on weight? The main reason to move to a quilt was always to save weight, for me at least. Bringing back the warmth and features of a traditional sleeping bag while still staying light is something you can’t beat. The Zpacks Mummy sleeping bag aims to do just that.

This bag would be great for those a little hesitant to make the switch to a quilt as well. I was a little skeptical about going back to a mummy bag after having used a quilt for so long, but this mummy doesn’t disappoint. For colder trips especially, if you want to cocoon yourself completely and have the extra features a mummy bag offers while staying ultralight, you can’t beat this new Zpacks sleeping bag.

Zpacks Mummy Sleeping Bag at A Glance


  • 10-degree: $559
  • 20-degree: $539

Weight / Fill Weight*:

  • 10-degree: 27.7 oz / 19.8 oz
  • 20-degree: 23.2 oz / 15.6 oz


  • Shell and liner: 0.51 oz/sqyd Ventum ripstop nylon
  • Insulation: DownTek 900-fill water-repellent goose down


  • Short: 68″ long / 60″ wide at shoulder / 40″ wide at feet
  • Medium: 74″ long / 60″ wide at shoulder / 40″ wide at feet
  • Long: 80″ long / 60″ wide at shoulder / 40″ wide at feet

*For a medium bag, which fits users up to 6’0

Intended Use

This mummy bag is for any ultralight hiker who still wants the comfort of a sleeping bag with a mummy hood. Its weight is on par with many popular backpacking quilts and can even function like a quilt when it’s warm. The 20-degree version will work for three-season use and keep you warm throughout the shoulder seasons.


Circumstances of Review

I have the 20-degree, short-length version of this sleeping bag and have taken it out for over 15 nights across the Utah desert. Temperatures ranged from 20 to 50 degrees Fahrenheit. I’ve used it in combination with a single-wall tent in addition to cowboy camping on a few nights.

Zpacks Mummy Bag Features hiker lays down inside fully-zipped zpacks mummy sleeping bag with hood up


The most important part of a sleeping bag is its insulation. Zpacks uses premium certified DownTek PCF-FREE water-resistant 900 fill power goose down. That’s a lot of words with a lot of positive connotations.

First of all, 900 is quite a high fill power, creating more loft and warmth with less weight. The DWR treatment helps the down to maintain loft even when there’s condensation overnight—and it’s PFC-free, which is better for the environment and the consumer. In addition, the down is responsibly sourced and certified under the Responsible Down Standard.

Vertical Baffles

The sleeping bag features vertical baffles to keep the down in place. They worked well for me, and I never had to redistribute the down anywhere. Zpacks also overstuffs each compartment by 30 percent to account for future down compression.


The square footbox is plenty roomy and has enough space to stretch your feet out in any way imaginable. I sleep with my legs and feet in all kinds of positions and my feet never felt cramped.hiker sits up on sleeping pad on sandy ground with legs inside blue zpacks mummy sleeping bag and feet sticking out bottom


The integrated hood is great for keeping you warm on colder nights. It’s adjustable via a full cinch cord, so you can lock down drafts in the cold but not feel trapped and sweaty when it’s warm.

Full-Length Two-Way Side Zipper

The zipper gives the bag a lot of versatility. You can open it completely and use the bag like a quilt or just unzip the footbox to stick your feet out. The possibilities are endless. It also features a zipper guard so it doesn’t snag. The draft tube and snap at the top of the zipper will also prevent any drafts from getting in on cold nights.

Dry Bag

The bag comes with a roll-top DCF dry bag for packing. Or you could reuse it for another purpose if you’re like me and just stuff your sleeping bag in your pack liner.

Black Liner Fabric for Drying

The inner fabric on all Zpacks bags is black and treated with PFC-Free durable water repellent. It’ll dry quickly if you put it inside-out in the sun.cowboy campsite in desert with black interior of Zpacks Mummy sleeping bag exposed

Temperature Rating

I had the 20-degree Fahrenheit bag and took it down to just above its rating multiple nights. According to Zpacks, “While our sleeping bags and quilts have not been tested for their International Standard Organization (ISO) rating, we estimate based on feedback and use that they are closest to the ISO ‘Transition Range.’”

The transition range is between comfort and limit, and I found this to be accurate. At 20 degrees Fahrenheit, it took me a bit to warm up but I did eventually, except for my feet. This could have been mitigated if I’d worn warmer socks or perhaps down booties. Around 30 degrees Fahrenheit, I was toasty warm in the bag.

I was typically wearing a fleece midlayer. I did find the hood sometimes difficult to keep around my head and occasionally wished for a second cinch cord on the opposite side to pull the bag itself a bit tighter to my neck. On warmer nights, I found it easy to use the bag more like a quilt to stay cool enough.

Sizing and Space

I’ve been a quilt user for a long time and was worried I’d feel too constricted in the mummy bag or that it would shift around during the night. I didn’t find this to be the case at all. I’m 5’4″ and had the short version of the bag, and I found this to be perfect.

I’ve had quilts of a short length before that were a bit too short, particularly when I sleep on my stomach. That wasn’t the case at all here. I found the bag to be plenty roomy throughout as well. I could curl up on my side and pull my knees up without issue, and roll over without the entire bag moving with me. Certain movements, like changing clothes, couldn’t be done with the zipper completely up, but that’s to be expected.

The sleeping bag was easy enough to get in and out of as well. I did find the zipper to snag occasionally, which made me even more glad for the zipper guard.

READ NEXT – Zpacks Duplex Review

Zpacks Mummy Sleeping Bag Pros

Warmth-Boosting Features

The hood, draft tube, and zipper snap really allow you to keep the heat in and the cold out. I sleep snug as a bug with all of these features in use. They work together as a great system.


While this sleeping bag works great for its intended use as a mummy bag, it can also be opened like a quilt. You can also just vent just your feet with the two-way zipper. There’s so much adjustability that it’ll work across a wide range of conditions. I used the bag like this on a warm night and thought it worked great.

Weight Savings

This fully featured mummy bag is competing in the weight category with quilts. Zpacks uses only the best and lightest materials to keep the weight down and features up.

Zpacks Mummy Sleeping Bag Cons

Hood Could Be More Adjustable

While the hood has a highly adjustable cinch cord, I still found it hard to keep it snug around my head. I often find myself just tucking my head into my jacket hood or further inside the bag instead. I’m still glad to have the hood, as I can put my hands in it and it still insulates more than not having one. I think increasing the hood depth could fix this small issue.

Down Loss

I’m finding that down is coming out of the bag at a higher rate than I’d expect based on my experiences with other quilts and sleeping bags. It could be that the material is very light, so that plumes can sneak through more easily, but that’s unclear. This isn’t a deal breaker, but down loss can definitely add up over time.


At over $500, these sleeping bags are definitely on the pricier side of sleeping bags and not a budget option. However, you are getting high-fill-power, premium down and quality ultralight fabrics, so I’d say the price is realistic.

Overall Value

I was honestly a bit skeptical of how much I would like this sleeping bag when I first got it, but it’s been great. I’ve come to appreciate all the features it brings and having a sleeping bag over a quilt again.

The 20-degree temperature rating is relatively accurate if you’re using the Transition Zone between true comfort and not-quite-shivering as your benchmark. If you’re looking for complete comfort at 20 degrees, you could upgrade to the 10-degree bag to make up the difference.

The light materials of this sleeping bag have been holding up well to harsh desert conditions so far. I would recommend the Zpacks Mummy sleeping bag to any ultralight hiker looking for a true mummy sleeping bag.

Shop the Zpacks Mummy Sleeping Bag

Comparable Sleeping Bags

Zpacks Classic Sleeping Bag

  • MSRP: $469
  • Weight: 23.2 oz

Feathered Friends Hummingbird Down Sleeping Bag

  • MSRP: $509
  • Weight: 1 lb 10.3 oz

The Zpacks Mummy Sleeping Bag was donated for purpose of review.

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Comments 1

  • Michael Laico : May 31st

    Awesome article, all th einformation I needed. After reading I thought this bag would work for me, probably will but I call Zpak and talked with someone that was no help at all. Zpack does not offer a compression sack, trying to get the bag volume so I could find my own compression sack. CS was no help at all on this, she was nt abl eto help and did not care. thank you for a great article!!!


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