Bivy sack, bivvy sack or bivI sack? The outdoor world might not have decided on the preferred name and spelling just yet, but one thing we can all agree upon is that these versatile little wonders are mightily useful. From emergency shelter to substitute tent, bivy bags have a wide range of uses and for some are an absolute ‘must-bring’ item whenever leaving behind the comfort of brick and mortar for a day, night or month or two in the wild. Just as potentially confusing as the name, however, is what makes a bivy a good one and what type is best for your outdoor adventures. To help you decide and shed some light on the matter, read on for our insights of the best bivy sacks of 2021!
- The best bivy sacks of 2021
- More about bivy sacks and why they’re great
- What to look for in a good bivy sack
Summary of the best bivy sacks in 2021
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|Products||Type of bivy sack||Weight||Waterproof?||Cost|
|REI Co-op Superlight Bivy||With poles||22oz (624g)||Yes, Pertex||$$$|
|MSR E-Bivy||Minimalist||7oz (198g)||Water resistant||$$|
|Alpkit Hunka||Minimalist||11.6oz (330g)||Yes||$|
|Outdoor Research Helium Bivy||With poles||16.8oz (476g)||Yes||$$$$|
|Rab Alpine Bivi||Minimalist||16oz (454g)||Yes, eVent||$$$$$|
|Black Diamond Big Wall Hooped Bivy||Minimalist||26oz (730g)||Yes||$$$$$$|
|Snugpak Stratosphere Bivvi Shelter||With poles||39 oz (1105g)||Yes||$$$|
|US Army Military Camo Bivy||Minimalist||40oz (1133g)||Yes, Gore-Tex||$|
|Sierra Designs Backcountry Bivy||Minimalist||14oz (397g)||Yes||$$|
|Rab Survival Zone Bivi||Minimalist||15.5oz (439g)||Yes, Hyperlite Storm||$$|
|Chinook Summit Bivy Bag||With poles||32oz (907g)||Yes||$$|
The best bivy sacks of 2021
Super light and surprisingly spacious, the REI Co-op Superlight Bivy is a compromise between a simple bivy sack and a one-man tent. Designed to be used throughout three seasons, both the top shell and the ripstop-nylon base are breathable, waterproof, and contain Bluesign Approved materials. A visor and mesh bug panel allow for extra ventilation without the interruption of pesky mosquitoes.
This single-pole bivy can stand independently but to take advantage of the full floor space you’ll need to stake the corners. The REI Co-op Superlight Bivy, weighing in at just under 25 oz, is not the lightest on this list. Instead, it’s a smart choice for multi-day backpackers who might enjoy a more generous sleeping space.
- Well ventilated
- Suitable for 3-season usage
- High priced
- Needs to be staked to use full floorspace
- Not the best zipper protection
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Weighing in at a miniscule 7oz / 198g, the super compact MSR E-Bivy is by far the most lightweight bivy sack on our list. Though it doesn’t offer the same weatherproofing as most of the other options, it provides a decent level of weather resistance for last minute missions in moderate conditions. The top of the bivy is silicone coated to fend off heavy dew, light rain and block out the wind. Additionally, the E-Bivy has waterproof Xtreme Shield floor to add warmth and durability when sleeping directly on the ground. This ultra lightweight bivy sack is the perfect option to chuck in your backpack, whether you think you’ll need it or not.
- Super lightweight
- Durable fabric
- Not fully waterproof
- No zip closure
If lots of awesomeness at a very, very reasonable price is your thing, it’s well worth taking a better look at the Alpkit Hunka. This no-frills, super functional and wallet-friendly little sack does everything you need a bivy bag to do. As if that wasn’t enough, it’s also the cheapest and the second lightest bivy in our review! It’s waterproof, breathable, and features a nicely tapered shape, a sculpted hood with dual drawcords and fully taped seams.
The only downsides to this sack are the lack of a side zipper for easy entry/exit and a slight lack of width and length. The first problem can be overcome with a little bit of wriggling, the second by upgrading to the Hunka XL, which weighs only 17oz and will set you back just £15/$20 more.
For more info read our full review of the Hunka.
- Weighs a tiny 11.65oz
- Very small pack size 5 x 6”
- 2.5-layer Ripstop nylon fabric
- Waterproof (HH 10,000)
- Hunka XL available for taller biviers
- Awesome value for money
- Wide at the shoulders (31.5”)
- A touch narrow at the feet (20”)
- A bit on the short side (85”)
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It’s tough, it’s durable, it’s completely waterproof, and the newly improved version is also even more lightweight than ever (14% lighter, in fact!). For a poled bivy sack, 16.8oz is impressively lightweight, competing fiercely with some of the non-poled options on our list. It even features no-see-um mesh, a guy line loop and stake hoops.
A couple of minor negatives include average breathability which could be better. Plus, it’s a little bit on the short side for very tall users (82”) and a little narrow at the shoulders (26”) for broader backed biviers.
Overall, however, the OR Helium is a beaut of a sack for those who want simple and lightweight functionality on multi-day missions.
- Very lightweight
- Fully taped seams
- Great weather resistance
- Features a mosquito net
- Breathability could be better
- A touch short and narrow
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When the weather’s doing its best to spoil your good time in the outdoors, the Rab Alpine Bivy comes into its own. This minimalist, 3-layer, fantastically weather-proof sack takes protection from the elements to a whole other level. Made for extreme alpine and mountaineering adventures, the Rab Alpine is very light, very tough and offers great breathability to boot. It features tough, Ripstop materials, eVent fabric, a reinforced underside for rocky surfaces, and a mummy-style design to fit technical sleeping bags. The only real downside to this bivy sack, in fact, is the cost. If you’ve got money to burn or it just happens to be payday, however, this just might be the bivy for you!
- Outstanding weather protection
- Great breathability
- Light (16oz)
- Reasonably spacious
- Very expensive
- Overkill for summer conditions
- Large pack size (4.7×12”)
The Big Wall Hooped Bivy by Black Diamond may be one of the most expensive options on our list, but if you’re looking for the best bivy sack for mountaineering and alpine climbing then stop your search now! With waterproof and breathable Todd-Tex fabric and a sewn-in wire to keep claustrophobia at bay, this tough cookie of a bivy sack is the closest you’ll get to a winter mountaineering shelter without actually setting up a tent!
To add to the Big Wall’s allure, appealing features include taped seams, dual-sided zippers, external loops for anchoring and a mesh panel for airflow and bug protection. All of that packs down to a very tidy, though certainly not tiny, 15 x 33 cm package.
- Suitable for extreme conditions
- Very weatherproof
- Good breathability
- Tricky to get in and out of through the small opening
More of a happy medium between a tent and a bivy sack, the Stratoshpere combines the features of both to form a beast of a bivi bag or a very miniature tent. Let’s start with the drawbacks – it weighs, quite frankly, a heck of a lot! At 39 oz, the Stratosphere is comparable to many one-person tents. But don’t be put off just yet! For all those added ounces, you really do get something very versatile and unique. This Bivvi Shelter is a gap-bridger between a tent and minimalist bivy bags. It’s very spacious, very robust, tough, and offers great weatherproofing. For those seeking an emergency shelter or lightweight nook for a few summer nights in the outdoors, this may well be overkill. For long-distance trekkers who fancy a bit of space at the end of the day without the weight of a tent, however, it might just be the solution you’re looking for!
- Reasonably priced
- Very spacious (42”W x 90”L x 37”H)
- Roll-away mosquito net
- Good water resistance
- Very well made
- Very heavy (39oz)
- Not the most breathable
- Large pack size (14 x 4 x 6”)
- Did we mention that it’s heavy?!
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When an item of gear carries the tag ‘military issue’, this usually suggests it’s a heavy-duty, frill-free workhorse. The Camo Bivy is just that type of bivy. It’s mightily heavy and not the most spacious sack out there, but contends with other ‘all-in’ bivies like the Stratosphere and Chinook Summit in terms of quality of build and value for money. It’s made of Gore-Tex fabrics for year-round weatherproofing, offers decent breathability and boasts some nice touches such as heat-sealed seams and a handy, bad-weather storm flap.
- Gore-Tex materials
- Military issue
- Reasonably priced
- Heat-sealed seams
- Solid weatherproofing
- Storm flap prevents the build up of snow or rainwater
- Very heavy (40oz)
- Not the most spacious (84” x 35” x 23”)
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The SD Backcountry has a lot going for it given its very wallet-friendly price. It weighs a tiny 14 oz, packs down to 3 x 10 inches and features both great breathability and awesome waterproofing. It also boasts a very useful bug mesh netting which allows you to pull down the hood on summer nights without worrying about your face becoming a midnight snack for peckish, airborne locals. On the downside, this isn’t as tough as other bivies such as the Rab Alpine, Alpkit Hunka or the OR Alpine, and its poleless design means the fabrics will be against your face while you sleep. Nevertheless, this bivy offers fantastic reliability and value for money.
- Weighs only 14oz
- Very reliable waterproofing
- Small pack size (3 x 10”)
- Made with Ripstop nylon materials
- Great breathability
- Bug netting
- Poleless design means the fabric is on your face
- Regular size (large is available) only 82” long
- Ripstop nylon is fairly thin (20D on the shell, 30D on the floor)
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Light, waterproof, spacious and breathable, the Rab Survival Zone is a true box-ticker of a bivy’s most desirable and ‘must have’ features. It’s also exceptionally well made, featuring tough, 70D Hyperlite Storm fabric and a zipless design to minimize weight and potential zip malfunctioning and/or fabric rippage. On the downside, the lack of a zip means a fair amount of wiggle-work to get yourself in there and, you guessed it, it’s pricey!
- Very light (15.5oz)
- Small pack size (4 x 10”)
- Made with 70D Hyperlite Storm material
- 95” long
- Very breathable
- Great weatherproofing
- Tricky to get in and out (no side zip)
A year-round kind of bivy sack that packs plenty of features into a spacious, robust design. The Chinook Summit is made with multi-day and extreme adventures in mind. This heavy-duty, well-made bivvy is a touch on the heavy side, but offers a very spacious sleeping area in addition to great weatherproofing, ventilation and comfort. It features a handy facial ventilation system, a duo of windows and enough head space to avoid insanity on longer trips. Ideal for the extreme adventurer who doesn’t mind a carrying a little extra weight!
- Plenty of head space – ideal for bedtime readers!
- Made with waterproof Ripstop nylon fabric
- Features facial ventilation system
- Very comfortable
- Tough and durable
- Spacious (91” long by 31” wide)
- Room for a sleeping mat
- Two windows
- Quite expensive
- Heavy (32 oz)
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More about bivy sacks and why they’re great
Before we get down to our review of the best bivy sacks, let’s take a look at why you might want to get your hands on one and what to look for.
I’ve already got a tent. Why do I need a bivy sack?
Whether you have a tent or not, taking a bivy along with you on your hike, climb, cycle or kayaking adventure is never a bad idea. At the cost of very little weight, a bivy will give you – and this is perhaps their most important benefit – a very light, effective emergency shelter than can be set up in seconds in extreme weather conditions.
For those who want to travel fast and light, a bivy might not afford the same roominess as a tent, but can perform much better in very cold conditions by containing your body heat and offering better waterproofing. The only downsides to choosing a bivy over a tent are the amount of room you have inside your shelter and, in some cases, the degree of weatherproofing.
Bivy sacks are ideal for anyone who:
- Wants a more advanced, comfy, high-performing emergency shelter
- Wants to travel ultralight
- Is planning alpine ascents
- Is an extreme minimalist
- Has no friends and/or prefers traveling solo
- Has issues with poles (many bivy sacks are pleasingly pole-free)
- Wants an easy-to-setup, cosy nighttime nook at the end of long days in the backcountry
- Wants to fall asleep watching the stars
Types of bivy sacks
Bivy bags generally fall into the following three categories:
Super light and compact but offer diddly squat in the way of weather protection. Good for the fair weather bivier venturing into terrain renowned for mosquitoes, midges or other mini, human-munching pterodactyls.
Pole free, ultralight and easy on the frills, these are ideal for the long-distance or three-season bivier who wants to travel light or bring along a just-in-case shelter for emergency situations.
These bivies are usually much more tent-like in design and thus offer a more spacious, weatherproof shelter ideal for more extreme conditions or claustrophobic campers. They’re usually made of tougher materials but, on the downside, can weigh more than double the lighter minimalist models.
What to look for in a good bivy sack
All bivies come with a different degree of waterproofing, which is measured on the ‘hydrostatic head’ (HH) scale. The higher the HH a bivy is, the more waterproof it is. The maximum HH you’re likely to find is 20,000, which means your bivy is not dissimilar to your average house in terms of its ability to keep of the wet stuff. A 1,000 HH bivy, on the other hand, will deal with a very light shower but not a lot more. Anything from 12,000 HH and up the way will keep you dry in even the heaviest of downpours. Although not all manufacturers mention the HH of their bivy, if you find one made of Gore-tex or eVent it’s sure to be waterproof.
02Breathability and ventilation
Your bivy can become a sticky, sweaty place without good breathability and ventilation. Gore-tex, eVent and Pertex are all examples of materials that offer great breathability in stickier conditions. Cheaper fabrics are likely to compromise on either breathability of weather resistance. Bivies with poles and more space inside are usually better breathers than those that lie on top of your body. Those with zippers instead of drawstring closures, moreover, allow you to ventilate manually on dry nights.
03Poled or poleless?
Back in the good old days, a bivy bag was a $1 plastic sheet you wrapped around yourself prior to several hours of suffering in a sweaty, airtight nest with straightjacket-like comfort. These days, poleless designs follow the same principle but, thankfully, offer far greater breathability, comfort and general convenience. They offer, essentially, a weatherproof cover for your sleeping bag.
Bivies that use poles or hoops, on the other hand, offer a lot more storage and wriggle-room, shed water and snow, and essentially function like mini tents. On the downside, they usually weigh and cost a lot more and take longer to set up than their poleless cousins.
For lightweight campers, a bivy that isn’t saving you at least a few ounces on the weight of a standard tent isn’t doing what it’s supposed to. Even if you simply want an emergency shelter to throw in the bottom of your pack, finding the lightest bivy available has to be high on the tick list. Before buying, however, make sure your would-be bivy hasn’t sacrificed any ‘musts’ (such as breathability, space, waterproofing) in order to cut down on weight. At the other end of the scale, if the bivy you’re considering is particularly heavy, then it’s time to weigh up whether or not you might be better just opting for a lightweight tent.
The comfort of your bivy depends on a variety of factors, some of which we’ve already covered above. In addition to waterproofing and breathability, however, size is also a key factor in making sure you don’t feel shrink-wrapped while you sleep. For taller users, aim for a sack over 90” in length. For those of a claustrophobic disposition or who do a fair amount of shifting in their sleep, a sack that it at least 30” at the shoulders and 25” at the feet will be most comfortable.
We’ve seen pretty much all the shapes, sizes, specs and features a bivy sack could possibly offer. Whether you’re looking for a bottom-of-the-pack emergency shelter or a nigh-on bombproof sack for more extreme adventures, we hope the above list has revealed your future bivy-to-be and that the pair of you spend many a happy, cosy night together out in the wild!
If you’d like to take your wild camping adventures to higher places then it’s worth exploring hammock camping. It offers all the flexibility of bivying but with more options of where to set up camp (or less, depending on where you are!)