Zpacks Mummy Sleeping Bag Review

Zpacks Mummy Sleeping Bag

Best Mummy Sleeping Bag For Backpacking | Lightest, Best Warmth-to-Weight

The Zpacks 20F Mummy Sleeping Bag is our pick for the singular best backpacking sleeping bag with the highest performance, traditional-style chassis in terms of warmth-to-weight ratio. This is a true ultralight sleeping bag, and top notch materials keep the weight to only 23.2 oz. Shop now.

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  • Weight: 23.2
  • Price: $539
  • Down: 900 fill power RDS hydrophobic goose down
  • Fill Weight: 15.6 oz
  • Fabric: 7D Ventum Ripstop Nylon
  • Estimated Comfort: +25 F
  • Pros: Ultralight. High warmth-to-weight. Converts to blanket.
  • Cons: Expensive. Slightly delicate.


It’s constructed with 7D Ventum ripstop nylon which is comfortable, breathable, wind/water resistant. We find it’s durable enough for most backcountry use. Its baffles are overstuffed (by 30%!) with 900 fill power RDS hydrophobic goose down.

Overstuffing reduces cold spots due to down drift, and is a very desired feature that adds minimal weight.

It’s even protected from snagging on its own zipper by the full length zipper guard. But like most ultralight sleeping bags, it’s a bit more delicate than average. Handle with care and it will last many years.

On colder nights, we love cinching down the hood to stay cozy, and on warmer nights, we love how it can fully unzip and convert into a blanket for better ventilation. Or just zip open the footbox to add airflow. It is available in three lengths (short, medium, long) and two widths (standard, broad) to accommodate a wide variety of bodies.

We have zero major knocks against this excellent product and feel it raises the industry-wide bar for backpacking sleeping bag performance.


It’s as simple as this. If you want the single best traditional sleeping bag money can buy, choose the Zpacks Mummy.

Zpacks Mummy Sleeping Bag Open for venting

Zpacks 20F Mummy Sleeping Bag Key Stats

Measuring medium length, standard width.

Price $539 | Weight 23.2 oz

ISO Comfort Rating: N/A

Our Predictive Comfort Rating: 25 F

Our Warmth-to-Weight Score: 4.1

Our Warmth-to-Cost Score: 2.4

Down: 900 fill power goose down, RDS-certified, DownTek PCF-Free water resistant goose down,

Fabric 7D Ripstop Ventum Nylon with C0 DWR (.51oz/sqyd)

Other Versions: Also available as a 10 degree bag.

Zpacks Mummy Sleeping Bag foot box closed zipper

Compared To Other Zpacks Sleeping Bags and Quilts

Compared to the Zpacks Solo Quilt, Classic Sleeping Bag, and Zip Around Sleeping Bag (all very excellent options) the Mummy is slightly heavier, slightly more expensive, and has a slightly lower warmth-to-weight ratio. This is simply due to the fact that the mummy design includes all the bells and whistles of a traditional sleeping bag: the fully enclosed back, the full-length zipper, and the hood.

While virtually all campers grew up with traditional sleeping bags and prefer them, we believe hoods and enclosed backs are the least hard working and most overrated parts of a sleeping bag. The down underneath one’s back is compressed by body weight, minimizing its insulation properties.

The hood is also compressed by the head, and further made redundant by the fact you are likely already carrying a hat and a fleece or puffy jacket with a built-in hood. To be clear, this is nothing against the Zpacks Mummy Sleeping Bag, simply our philosophical perspective that quilts are superior in performance to sleeping bags.

However, we do think sleeping bags close the gap somewhat with quilts when it comes to winter camping, and the 10F version would be a great option for very cold weather.

Warmth-to-weight performance rankings as follows within the Zpacks sleep system family:

  1. Zpacks Solo Quilt 20
  2. Zpacks Classic Sleeping Bag 20
  3. Zpacks Zip Around Sleeping Bag 20
  4. Zpacks Mummy Sleeping Bag 20

In Conclusion

The Zpacks Mummy Sleeping Bag is the best traditional sleeping bag on the market, and the only options that eclipse it in terms of performance are quilts, and hoodless sleeping bags. This raises the bar on mummy bag, is best-in-class, and excellent in every way. We highly recommend this sleeping bag!

Read about more great sleeping bags in our guide to the Best Sleeping Bags of the Year, or crank up the performance further with our guide to the Best Camp Quilts of the Year.

Check out the hoodless version of this sleeping bag, the Zpacks Zip Around.