ProView – Sierra Designs Night Cap 20°

Picture this: it’s 2am – you’ve been lying semi-awake in your tent for the past hour trying to convince yourself that you don’t actually have to go to the bathroom. After denial gives way to desperation you decide to brave the cold air. You go to unzip your sleeping bag when the unthinkable happens – the zipper snags. It’s dark, you don’t want to wake your tent-mate, and the urge to relieve yourself is becoming unbearable. The struggle turns monumental as you grasp blindly for the liner material. “Why does this stupid zipper always get stuck here?” you ask yourself. All of a sudden a mountain lion attracted by the sound of trapped prey pounces on you! The annoying dilemma is now a fight for your life. Nearby a brown bear is lumbering when it, too, is drawn in. America’s top carnivores are now fighting over the piece of meat that is your gift-wrapped body. And to think: this all could have been avoided if you just had a zipperless sleeping bag. 

Sierra Designs Night Cap 20°

Product Description: Based on our bestselling Cloud Sleeping Bag, but now in a lower cost fully recycled synthetic package, the Night Cap Sleeping Bag features a zipper-less design with an integrated comforter for all the comforts of home in the backcountry. The Night Cap also incorporates our patented self-sealing foot vent and a pad sleeve, allowing increased ventilation for hot sleepers and movability for wiggle worms, side, and stomach sleepers.

Offer price: MSRP: $169.95

  • Quality
  • Features
  • Durability
  • Ease of Use
  • Weight/Packability
  • Eco-Friendly


The Sierra Designs Night Cap is an innovative take on a product that has been around for decades. The zipperless comforter system hugs like a blanket and stays tucked in all night. The foot vent allows for some additional ventilation, and the soft recycled polyester liner will make you think you’re sleeping in a cloud. If you ever been frustrated by sleeping bag zippers, the Sierra Designs Night Cap is a product you will want to consider closely.



  • Warm and comfortable
  • Easy access foot vent
  • Sleeping pad sleeve
  • No zippers to catch hair
  • Comes with a mesh bag for storage
  • Made from recycled materials and plastic bottles


  • Can be restrictive at times
  • Hard to wrap up when laying in certain positions
  • No internal pocket
  • No insulation on pad-sleeve area
  • Pad sleeve doesn’t accommodate large sleeping pads

In 2014, Sierra Designs introduced their new zipperless sleeping bag, an innovative design that replaced the zipper with a clamshell comforter system that tucked into place instead of zipping. I’ve long looked at zipperless sleeping bags with an interested but skeptical eye. This summer I got the opportunity to try their newest version: the Night Cap 20°. This bag accompanied me on a few car-camping trips and an overnight excursion to a nearby National Forest.


Sierra Designs has removed the zipper on the Night Cap by replacing it with an innovative comforter system that acts similar to a blanket on a bed – it tucks into the bag opening and seals the bag without any mechanical fixtures. It really is an interesting feature that works surprisingly well. The comforter also has a small “corner” built into it that tucks into your shoulder and keeps the comforter from pulling out. Additionally, the section of the comforter that is near your waist is sewn into the bag to keep heat from escaping. It can be a bit overwhelming at first to find where to slide into the bag, but once you figure it out it’s like slipping on a glove. In fact, at times I found it to be a little too restrictive for my tastes – this however is pretty common for mummy bags, and is something I just have to get used to. 

The recycled polyester liner is comfortable and soft to the touch, and the zipperless design means that you never catch your hair or have the feeling of a zipper against your skin. Additionally, it is fairly easy to get in and out of the bag. Never again will you have to unstick a zipper in the middle of the night.

Another interesting feature of the bag is the “self-sealing” foot vent. This is basically just a hole that you can stick your feet out of for ventilation. The hole has overlapping insulated portions that should still keep your feet warm in cold weather. Because it is the middle of summer, I found myself using this feature a lot to keep from overheating. In fact, the foot vent combined with the comforter means that the bag has a really wide range of temperatures in which it can be used. 

One of the features I was most excited about was the sleeping pad sleeve on the back of the bag. This sleeve wraps around your sleeping pad and keeps the bag from rotating in the middle of the night when you turn over. However, to my great disappointment, I found that I can’t use this feature with my Thermarest NeoAir XTherm MAX because it is 25” wide; the Night Cap will only accommodate pads up to 20” wide. 

I would like to see a couple of additional features in later iterations of this bag. Primarily, I really missed having an internal pocket for my phone and camera batteries. I like to keep them warm at night to keep them from dying, and an internal pocket is usually the best way to achieve this. Also, it would be nice to have a button or a monkey fist + loop to keep the comforter closed. This way you wouldn’t ever have to worry about the bag opening when you turn over in the night. Finally, some type of adjustable sleeping pad sleeve would be nice for larger pads.


Because this is a 20° synthetic bag, it is relatively heavy. However warmth in the backcountry is invaluable, and this bag still weighs less than some of my other synthetic bags. I measured the bag at 3lb 6.6oz with the included stuff sack – slightly more than the 3lb 1.4oz Sierra Designs claims on their product specifications. This is equivalent to a 1.5L Nalgene filled almost to the top with water. While this is a fair bit to add to your pack, a down sleeping bag with the same temperature rating will cost easily twice as much as the Night Cap.

I do wish that this bag came with a compression sack instead of just a stuff sack. The stuff sack comes out to about 16.5” long with a 9.5” diameter when filled; this made for a pretty tight fit in the bottom of my 65L Osprey Pack. A compression sack might make it slightly easier to fit, although it may decrease the efficacy of the insulation over time.


I received this bag in the dead of Colorado summer – not exactly the ideal time to test the lower limits of the bag. However, one benefit to trying a 20° degree bag in the summer is that I got to try a variety of options to shed heat. First, I really enjoyed the foot vent on the bottom side of the bag. While many sleeping bags have a zipper at the foot, I’ve never actually used it; I never cared enough to sit up in the middle of the night and reach to zip or unzip a bag. The Night Cap, however, makes it easy to just slip your feet out or back in without fully waking. I’m curious how the vent will perform in the cold, but I believe the overlapping insulation layers will seal out cold air effectively. Additionally, the comforter that wraps up so nicely in cold weather opens up wide to release heat. 

One thing of concern is the lack of insulation where the pad sleeve connects to the bag. Sierra Designs obviously went with this design to reduce weight and to lean on the warmth of one’s sleeping pad. However, if you have a sleeping pad that isn’t very warm, this might become a cold area. Additionally, if you have a large pad (like mine) that will not fit into the sleeve and you roll over in the middle of the night, you might possibly expose your back to the cold air. I did not actually experience this, but it’s something to be aware of.

I was initially skeptical of the comforter design, but after some use I’ve grown to like it. It tucks nicely around your shoulders like a blanket, and it seems to stay in place throughout the night. It is easiest to use when sleeping on your back and on your left side – when sleeping on your right side or on your stomach, it can sometimes be a little awkward to tuck effectively. I’m really looking forward to seeing how it performs in super cold conditions.

Friendliness to the Earth

The Night Cap is constructed entirely of recycled materials including tough, 20D recycled polyester. Additionally (although it was a little unclear) Sierra Designs’ “SierraLoft” insulation is apparently made from recycled plastic bottles – a great way to reuse a product that never degrades. Whatever magic they are doing behind the scenes to turn plastic bottles into insulation seems to be working because the bag is really warm.

The Final Word

Overall, I am pleased with the Night Cap 20°; I didn’t get to test the lower limits of the bag, but I was left confident that it would keep me warm on chilly nights. The zipperless comforter certainly takes some getting used to, but quickly becomes a nice way to become a burrito. The foot vent is easy to use without fully waking, and the recycled polyester feels like a cloud against the skin. While the Night Cap may be a bit too much bag for summer nights, it will definitely be in my backpack for every Fall and Spring trip.

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About the Gear Tester

Outdoor Prolink Pro
Daniel John
Adventure Photographer :: Daniel John Photography

Daniel John is a commercial and editorial photographer in Boulder, Colorado with a passion for travel and adventure. Daniel’s obsession with photography was cultivated during a year-long backpacking trip through Asia and Oceania where he documented incredible places and people. When he isn’t editing photos, you can find him exploring the mountains and streams of Colorado. You can connect with him on Instagram (@ImagesByDJ) or through his website.

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