Sierra Designs Night Cap Sleeping Bag 20F review: a super cozy, zip-free design for comfort in car camping

This groundbreaking sleeping bag design does away with the annoying zip and lets you snuggle up in a surprisingly versatile cocoon

Sierra Designs Night Cap Sleeping Bag 20F
(Image: © Julia Clarke)

Advnture Verdict

If you’re tired of cold, scratchy zips when you go camping and seeking some true home comforts, look no further than this plush, zipperless sleeping bag


  • +

    Super cozy and warm duvet-like design

  • +

    Surprisingly spacious

  • +

    No cold, scratchy zip

  • +

    Self-sealing foot vent for fast cooling off

  • +

    Integrated sleeping pad sleeve

  • +

    Fully recycled insulation


  • -

    Big and bulky

  • -

    Too warm for summer camping

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Sierra Designs Night Cap Sleeping Bag 20F: first impressions 

Sierra Designs has officially broken the mold with the design of this zipplerless sleeping bag. Usually you have to choose between a zip-up bag or a zip-free camping quilt, but the Night Cap offers the best of both worlds with a duvet-like design that allows you to enjoy the comforts of home and no cold, annoying zip pressing against you or letting a draft in. This synthetic bag has an oversized blanket flap that feels just like snuggling under your comforter at home and keeps you toasty at temperatures well below freezing. 


RRP: $184.13 / £159.95
Unisex: Yes
Sizes: Regular/long
Materials: Liner: 20D Recycled Polyester; Shell: 20D Recycled Polyester; Insulation: SierraLoft Eco Synthetic
Weight: 3lbs / 1.37 kg
Length: 78" R 82" L / 198 cm, 213cm L
Fill: Recycled synthetic
ISO Comfort Rating: 34°F / -1.6°C
ISO Limit Rating: 23°F / -5°C
Colors: Blue/gray
Best use: Car camping, glamping 

An integrated sleeping pad sleeve keeps your pad underneath you so there’s no chance of rolling off onto the cold ground and a snuggly hood lets you bundle up on cold nights. If you get too warm, just stick your feet out the self-sealing foot vent and toss the blanket flap aside. Even though this bag is very much of the mummy-shaped variety, you’ll find there’s plenty of room to sprawl out a little. With its considerable size and heft, you won’t be hauling this on a backpacking trip any time soon, but for car camping and glamping, you’ll never be cozier than in this bag. 

Sierra Designs Night Cap Sleeping Bag 20F: in the field 

Sierra Designs Night Cap Sleeping Bag 20F

Cool off by sticking your feet out of the self-sealing foot vent (Image credit: Julia Clarke)

I’ve been testing out camping quilts this year and tried out this sleeping bag to see if it makes a worthy replacement for a sleeping bag. While it’s not super lightweight and intended for ultralight backpacking the way a true camping quilt is, I feel like I’ve discovered a whole new world of comfort when it comes to car camping and I’m actually not sure I’m going back to a zipped bag for freezing nights when I don’t have to hike in with my gear.

Whereas your typical sleeping bag is a pocket that zips up to form something vaguely rectangular, this groundbreaking design from Sierra Designs is kind of like you’ve taking your favorite comforter from home, swaddled yourself in it the way you do on a cold night, and then stitched it up. The plush insulation, cinched hood and blanket flap make it amazingly cozy and frankly it’s plenty warm for any temperature I’d be likely to go car camping in. It’s honestly like snuggling into my own bed at night.

Sierra Designs Night Cap Sleeping Bag 20F

A handy pocket keeps your sleeping pad in place (Image credit: Julia Clarke)

That said, after an hour or two I do tend to get warm, even on freezing nights, so I love the self sealing foot where I can just stick out a foot or two and instantly cool off. It has a built-in sleeve for my sleeping pad which I thought might be annoying but it’s actually great to keep from rolling off the pad in the middle of the night. I’m also a bit of a sprawler and sleep on all four sides and was pleasantly surprised to discover that I can easily curl up on one side and sleep on my back with one knee bent out to the side no problem.

This bag isn’t super light, and because it’s synthetic it honestly doesn’t compress down particularly small either. It’s the bulkiest bag I own but most of my gear is geared towards backpacking trips. I certainly wouldn’t be stuffing this into my hiking backpack as I’d have no room left over for anything else, but it’s definitely my top choice for car camping and glamping going forward, and it’s not a bad price either for such comfort.

Here’s how it performed:


It’s one of the snuggliest, coziest sleeping bags I’ve ever wrapped myself up in, and I love having space to spread out. 

Warmth and breathability

We’ve not had too much cold weather lately, but I’ve been super toasty on nights where it gets close to zero in this bag and definitely would trust it for all car camping. There’s nothing sweaty about it, and the foot vent and blanket flap make it easy to cool off. 

Sierra Designs Night Cap Sleeping Bag 20F

This sleeping bag doesn't pack down the smallest (Image credit: Julia Clarke)


This doesn’t compress down small at all – it’s more than twice the size of my sleeping pad packed down, so it’s reserved strictly for car camping. 


So far, so good, plus there’s no zip to break. 

Julia Clarke

Julia Clarke is a staff writer for and the author of the book Restorative Yoga for Beginners. She loves to explore mountains on foot, bike, skis and belay and then recover on the the yoga mat. Julia graduated with a degree in journalism in 2004 and spent eight years working as a radio presenter in Kansas City, Vermont, Boston and New York City before discovering the joys of the Rocky Mountains. She then detoured west to Colorado and enjoyed 11 years teaching yoga in Vail before returning to her hometown of Glasgow, Scotland in 2020 to focus on family and writing.