The world's most in-depth and scientific reviews of outdoor gear

Sierra Designs Cloud 20 Review

A zipperless design with a traditional mummy bag shape.
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Price:  $330 List | $247.46 at Amazon
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Pros:  Easy zipperless closure, built-in foot vent, wider than average dimensions, fair price
Cons:  Drafty hood, limited lower body ventilation, uninsulated sleeping pad sleeve
Manufacturer:   Sierra Designs
By Jack Cramer ⋅ Review Editor  ⋅  May 7, 2019
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64
OVERALL
SCORE


RANKED
#11 of 14
  • Warmth - 20% 6
  • Weight - 20% 6
  • Comfort - 20% 7
  • Packed Size - 15% 7
  • Versatility - 15% 6
  • Features & Design - 10% 6

Our Verdict

Tired of fussing with sleeping bag zipper but fear a chilly draft in an open backcountry quilt? Sierra Designs has you covered. The Sierra Designs Cloud 20 encloses you like a traditional mummy sleeping bag but without the hassle of finicky zippers. Instead, a pair of overlapping flaps open for easy entry and closes the to seal the heat inside. Our testers found it to be an innovative and comfortable design. There are drawbacks, however, to the bag's thermal efficiency and versatility that are had to ignore. We also consider its relative, the Sierra Designs Backcountry Bed to be an even more comfortable zipperless option.


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Our Analysis and Test Results

Zippers are so 1990's. Sierra Designs can help you embrace the 21st century with several zipperless sleeping bag offerings. Our testers prefer their Backcountry Bed the most, but their Cloud also has some innovative features that we like.

Performance Comparison


Of the two innovative zipperless bags from Sierra Designs  we prefer the "comforter" closure of the Backcountry Bed (blue) over the angled flap on the Cloud (red).
Of the two innovative zipperless bags from Sierra Designs, we prefer the "comforter" closure of the Backcountry Bed (blue) over the angled flap on the Cloud (red).

Warmth


Sierra Designs gives the Cloud we tested a 20°F rating, but its performance on the industry-standard EN test is a little lower (15° lower limit). Our testers thought both the manufacturer and EN ratings seemed generous. We thought it felt comparable an average bag with an EN lower limit of 25°.

This looks like pleasant way to spend a morning  right? Maybe  but on a truly chilly morning the only thing insulating the back of the bag is two thin pieces of nylon.
This looks like pleasant way to spend a morning, right? Maybe, but on a truly chilly morning the only thing insulating the back of the bag is two thin pieces of nylon.

Potential users should also be aware that to save weight this bag doesn't have any insulation on the bottom side of the torso area. Thus, a good sleeping pad is mandatory for sleeping comfortably with this bag.

Taken inside the Cloud  this photo shows light shining through the uninsulated rectangle on the underside of the bag. At the bottom and sides of the image the shadow of down insulation is visible.
Taken inside the Cloud, this photo shows light shining through the uninsulated rectangle on the underside of the bag. At the bottom and sides of the image the shadow of down insulation is visible.

Comfort


Nestling into this bag is a pleasant experience. The closure flaps come close to achieving the familiar feel of the blanket like your are probably use to sleeping with. Its overall comfort, however, did not equal its Sierra Designs cousin, the Backcountry Bed, because the Cloud's narrower dimensions leave it with the same constrictive feel as many other mummy bags.

The Sierra Designs Backcountry Bed (left) and Cloud (right) both come with aesthetically pleasing nylon stuff sacks.
The Sierra Designs Backcountry Bed (left) and Cloud (right) both come with aesthetically pleasing nylon stuff sacks.

Packed Size


Like a lot of bags reviewed, the Cloud comes with a simple drawstring stuff sack that's unable to compress it effectively. With a third-party compression sack, we were able to pack a size long to 8.4 liters in volume. This leaves it with an above average packed sized, comparable to the similarly warm, but synthetic, Mountain Hardwear Lamina.

Versatility


There are several different aspects of this bag that harm and hurt its versatility. The foot box, for example, has a slit on the underside for your feet to escape. This lets you keep the bag on while you shuffle around awkwardly or sit and sip your morning coffee. The same slit, however, isn't very effective at venting should your lower body overheat.

The author is able to poke his feet and "fashionable" footwear out the built-in vent on the lower end of the Sierra Designs Cloud.
The author is able to poke his feet and "fashionable" footwear out the built-in vent on the lower end of the Sierra Designs Cloud.

The main entry/exit flaps make up for this to some degree with a range of configurations for different outside temperatures. But when the bag really hits the pad, you still have fewer options than a traditional full-length zipper bag if your legs start to sweat.

Features and Design


To cinch the hood tight, the Cloud features a drawstring like that found on most sleeping bags. For this drawstring to be effective, however, the main closure flap must be pinned beneath your body on the left side of the bag. When you roll onto your right side, it's difficult to keep this flap pinned down. But without it, the hood will not stay cinched closed.

The Sierra Designs Cloud (top) and Backcountry Bed (bottom) both feature the same fabric sleeve to attach the sleeping bag to a sleeping pad.
The Sierra Designs Cloud (top) and Backcountry Bed (bottom) both feature the same fabric sleeve to attach the sleeping bag to a sleeping pad.

Sierra Designs also brags about a sleeve on the underside of the bag that ensures you can't slide off your sleeping pad in the middle of the night. That's true, but unlike some other bags, this pad attachment system isn't removable if you prefer to save weight and not to use it.

Best Applications


This zipperless bag is great for the same things as a traditional sleeping bag, but it's probably best for longer backcountry trips where you can savor its considerable comfort night after night. The uninsulated sleeping pad attachment area, however, necessitates that it be used with a good sleeping pad. Therefore, it might not be the best choice for hammock or portaledge overnights.

Value


For its middle of the road performance, the Cloud comes with a middle of the road price. At its full MSRP of $330, we don't consider it to be a particularly good value, but bigger fans of the no-zipper design will likely disagree. For a few bucks more you grab a Nemo Riff 30, which offers a similar degree of comfort with better performance in other areas.

We don't think the drafty closure flap makes a lot of sense in the 20F version of the Sierra Designs Cloud because at those temps you don't want a draft. However  it makes much more sense in the 35F version shown here that we didn't formally test.
We don't think the drafty closure flap makes a lot of sense in the 20F version of the Sierra Designs Cloud because at those temps you don't want a draft. However, it makes much more sense in the 35F version shown here that we didn't formally test.

Conclusion


Although most of our testers weren't fond of the Cloud, it did garner some passionate supporters. These supporters liked its simple flap closure design that provided a similar feel to sleeping with an ordinary blanket. Its critics, however, maintain the same design limits its versatility and adds unnecessary weight. The bottom line: if the no-zipper concept sounds like heaven to you, don't let this review discourage you. The Sierra Designs Cloud 20 and Backcountry Bed are both decent bags whose innovative designs are sure to please many.


Jack Cramer