During a backpacking, camping, or climbing trip, setting up a tent can seem like a real pain in the ass. You have most likely found yourself wondering why the heck you keep fighting with a tent and everything that comes with it. Lucky for you there is another option, the bivy sack.
A bivy sack is a lightweight, compact, and simpler alternative to the traditional tent. They go from your bag to completely ready to go in less than a minute and there is no extra parts and pieces to hassle with.
Finding the bevy bivy sack may seem like the best thing since sliced bread and they absolutely can be. There are going to be sacrifices made in terms of your usual outdoor sleeping system, however, the juice is worth the squeeze. Below you’re going to find out what a bivy sack is, what they do well, and what they don’t, and whether or not a bivy is the right choice for you.
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Table of Contents
- What is a bivy sack?
- Benefits of Bivy Sacks
- What to look for in a bivy sack
- Downside of bivy sacks
- Best Bivy Sacks
- Which bivy sack is right for me?
What is a bivy sack?
Bivy sack is short for “bivouac sack” and was originally designed for climbers and other outdoor enthusiasts who needed a lightweight shelter for multi-day ascents on large walls. The initial concept of a “bivouac” or bivy sack was to provide a compact and lightweight alternative to a tent, which provides shelter an warmth in limited size and space while in the outdoors.
Today bivy sacks are used by mountaineers, campers, and backpackers who want to have an ultralight and minimalist option, rather than packing a tent and all the crap that comes along with it (tent poles).
Whether you prefer camping, kayaking, backpacking, climbing, or a cycling trip, a bivy sack is one weapon that everyone should have in their outdoor gear arsenal.
Benefits of Bivy Sacks
There is an ongoing argument among backpackers, climbers, and bikepackers whether or not a bivy sack is worth the sacrifice in space that a tent offers. While they may not be the perfect fit for everyone, there are a number of reasons to consider opting for the bivouac sack.
1. Bivy sacks are ultralight
They are perfect for the ultralight adventure that values saving pounds while sacrificing space inside. Bivy sacks are not meant to be spacious on the inside, so you need to get used to sleeping in closed quarters alone. They are nearly always lighter than an ultralight tent and are always significantly less expensive.
2. Protect you from the elements
A good bivy sack will offer protection from the elements, be it rain or wind. There are models that are rated for snowy conditions, however, those are more of an extreme bivy sack. Most, if not all, bivy sacks are at the very least waterproof and rated for cold conditions.
3. Small and compact packed size
The fact that they are small and compact by design, means that their packed size is much less than a tent. They often pack down into the size of a large water bottle and take up little to no room. It’s common for backpackers to leave their sleeping bag inside the bivy sack and roll them up together and it still fits in the sleeping bag stuff sack.
4. Simple to setup
Setting up a bivy sack takes less than a minute and if you keep your sleeping bag inside of it, you kill two birds with one stone. One of the biggest pain points in setting up camp is fumbling around with the tent poles, stakes, and guy lines. A bivy sack eliminates the need for any excess gear while providing a similar level f protection.
5. Keeps you warm at night
Due to their compact design and snug fit, a bivy sack will increase the rating of your sleeping bag by 5-10 degrees. This is a trick that seasoned backpackers and climbers have been employing for years to increase warmth and reduce overall pack weight.
6. 4 season ratings
There are bivy sacks that are rated for 4-seasons, making them an adequate replacement for an expensive ultralight tent. They are rated for wet weather and cold conditions that you will experience in the winter months. Keep in mind, not all bivy sacks are made for 4-seasons, so don’t make the mistake of taking a knife to a gunfight.
What to look for in a bivy sack
Bivy sacks come in a number of variations, however, there are a few common factors that every good bivy sack will address.
One of the biggest reasons campers and backpackers opt for a bivy sack is the size and weight. If you are only going to save a few ounces over bringing a tent then a bivy sack is not doing its job. Finding a lightweight bivy sack that doesn’t sacrifice quality and comfort is a major consideration while maintaining ultralight status is paramount.
Comfort is a factor that cannot be overlooked whenever you’re thinking about changing where you sleep at night. After all, this is going to be the place that you’re spending a third of your time on outdoors adventures. You want to be sure that you don’t feel like a sardine, a bivy sack should be snug and cozy but not tight and closed in.
Considering that a bivy sack is meant to be used in the outdoors in all types of environments, it’s important that yours offers protection from the elements. If you are expecting cold weather and rainy conditions your bivy sack should be rated for low temperatures and made of waterproof material. Take a look at the HH (hydrostatic head) scale, the higher the number the more waterproof the bivy sack.
Bivy sacks are small and compact by nature and without proper ventilation, they become muggy and uncomfortable. The cheaper the material the more prone they are to becoming sticky and sweaty at night. Don’t sacrifice breathability for a small savings, you’ll end up regretting it.
Getting chewed alive by bugs while you sleep is the worst thing that can happen in any outdoor scenario. Bugs aren’t a problem everywhere, however, if you expect them to be a nuisance consider a bivy sack with a bug net. They will weigh a little more, but you get to feel like a person in the morning rather than a piece of itchy meat.
Downside of bivy sacks
With all the great feature of a bivy sack, you should throw out your tent and go hardcore, right? Not so fast, while they are a decent option, there are negatives when considering a bivy sack.
There simply is not that much room inside a bivy and this is a stark contrast when compared to a tent. You are going to need to find a place for all your other gear and in constant bad weather, a tent is a better option.
If you plan on backpacking and sleeping with another person a bivy sack will not work. They are only made for one person and the only option would be to set up a tarp over both of your bivy sacks as a makeshift shelter.
If bugs are an issue a bivy sack sucks. While there are a couple of bivy sacks that offer big netting, the lions share of bivy sacks don’t. So if you expect to be outdoors in a place where bugs are an issue, consider using another type of shelter.
Condensation is an issue in every type of outdoor shelter and a bivy sack often seems to magnify the problem. There is a natural amount of water vapor that escapes your body as you breathe and sleep and it needs somewhere to go. While it’s not a major issue, waking up with a wet sleeping bag is the worst.
Disadvantages of bivy sacks
- Need a dry place for your gear
- Not much room inside
- Only made for 1 person
- Lack of bug protection
- Condensation is an issue
Best Bivy Sacks
The best bivy sack is the one that you are most comfortable in and protects you from the elements. Here are our top picks for the best bivy sacks available today.
Survive Outdoors Longer Escape Bivy
- EMERGENCY SLEEPING BAG OR BLANKET: Get inside the bivvy like a sleeping bag for the unexpected night out or turn the bivvy inside out to use as an emergency blanket if you're not ready to lay down.
- 70% HEAT REFLECTIVITY: Stay warm in the fiercest conditions with a bivvy that reflects 70% of your body heat back to you to prevent heat loss and trap warm air.
- LIGHTEST BIVVY ON THE MARKET: This bivvy bag can be used for camping, hiking, or biking for an emergency shelter you can rely on and is the size of a 12 oz. soda can when packed up
- DURABLE, REUSABLE, & QUIET: Have confidence your shelter won't let you down or cause undue stress. Unlike mylar or polyester, this bivvy features a quiet, tear-resistant material that won't shred to pieces if punctured or fray your nerves by rattling loudly in the wind.
The inside layer of Survival Outdoors Bivy Sack has an inside layer that reflects 80% of your body heat, keeping you warm on cold nights. It is extremely lightweight, the emergency version weighs in at 8.1 ounces. The waterproof seams include a drawstring hood and there is a zipper on the side so you have the ability to seal out the elements.
These bivys are made for emergency situations, however, when used with care they can be used for activities from climbing to backpacking. Survival Outdoors offers the Escape, Thermal, and Emergency versions of the Bivy that are all designed for different backcountry scenarios.
- Season: 3 season
- Packed weight: 8 ounces
- Dimensions: 64 x 34 inches
- Packed size: 8.5 ounces
Woodland Camouflage Waterproof Bivy
- NSN: 8465-01-416-8517
- Woodland Camouflage
- Made in the USA
The Woodland Camouflage Bivy sack is made in the USA with GoreTex material that will keep you dry in rainy conditions. It is designed to be used in extreme environments and is a little bit on the heavier end, coming in at 2 pounds. It weighs about the same as an ultralight tent, however, it is a fraction of the cost and way easier to set up and take down.
The packed size is slightly larger than other bivy’s, but it is still smaller than a compressed sleeping bag. There isn’t any support for the hood, so plan on it touching your face while you’re sleeping. A waterproof bivy can be prone to condensation, however, the GoreTex material does a great job at letting the condensation escape while keeping the water at bay.
- Season: 4 season
- Packed weight: 35.2 ounces
- Dimensions: 84 x 30 ounces
- Packed size: 5.5 x 9 inches
ACU Digital Bivy Cover
- ACU Digital Camouflage
- 100 percent water/wind proof outer layer. Designed to enclose patrol and intermediate cold weather sleeping bag for the complete modular sleep system.
- Nonflammable, machine washable.
- 2 way nylon zipper that allows for top or bottom ventilation (the zippers are non locking sliders which self repairs if jammed or snagged). Can be used alone for warmer temperatures.
The ACU Digital Bivy sack has a digital camouflage design on the exterior, giving it a cool look from the outside. It’s a strong and lightweight bivy bag that packs down into a small area. It’s waterproof and has adequate ventilation, so condensation is not an issue.
The zipper operated in both directions, so you can choose to air it out from either the top or bottom. The overall size is 80 inches long and 30 inches wide and it can be fully enclosed. It keeps you warm in temperatures down to 30 – 40 degrees.
- Season: 4 season
- Packed weight: 14 ounces
- Dimensions: 80 x 30 inches
- Packed size: 12 x 12 inches
Black Diamond Twilight Bivy
- The minimalist four-season Black Diamond Twilight Bivy is built from water-resistant and breathable NanoShield fabric that keeps weight to an absoulte minimum and packs down incredibly small making it ideal for an emergency shelter or bag cover
- Built with a zippered entry across the shoulders it's easy to get into and use while sitting up.
- Framless construction to minimize weight Proprietary NanoShield single wall fabric Year round performance
The Black Diamond Twilight Bivy is a 4-season, minimalist bivy sack that is made of Black Diamond’s proprietary NanoShield material. NanoShield is extremely water resistant and breathable, for a single layer fabric, it’s one of the most versatile options out there. The face of the fabric is finished with the waterproof coating and the inside has a microporous that makes it breathable.
The waterproof rating is effective in light to moderate rain, however, if heavy rain is in the forecast a tarp or other layer will keep the rain out. It has a zipper that runs across the shoulders, so it’s a breeze to get into and sit up.
- Best use – Backpacking, camping, climbing
- Season – 4
- Packed weight – 10.7 ounces
- Dimensions – 82 x 33 inches
- Packed size – 3 x 5 inches
Outdoor Research Molecule Bivy Long Bag
- Fabric Performance: Waterproof, Breathable, Fully Seam-Taped, Durable, No-See-Um Mesh, Hydroseal Floor, Anti-Fungal Coating on floor
The Outdoor Research Molecule Bivy has a clamshell design with overlapping zippers that provide great ventilation in all weather. It has a 70-denier floor with an antifungal coating so it can handle all 4 seasons. The foot box is vented and increases ventilation without creating condensation.
- Best use – Backpacking
- Season – 3 or 4
- Packed weight – 22.9 ounces
- Dimensions – 90 x 25.4 inches
- Packed size – 5 x 14 inches
Which bivy sack is right for me?
Every bivy sack has qualities that perform well in certain situations and not so great in others. To determine which type of bivy sack is the right fit for you, consider the terrain, the weather, ground conditions, and how much weight you want to carry.
Another consideration is how you sleep. This is often overlooked. however, if you are able to fall asleep anywhere and you don’t move that much a bivy sack is a great option. If you toss and turn while you sleep and need room in the evening a bivy sack isn’t going to be your best option.
Bivy sacks are a great option for certain situations and while they are lightweight and compact, they won’t completely replace the need for a proper tent. Taking everything into consideration, the best bivy sack is always good to have as an option on your next adventure.