Best Bivy Sack: Sleep Comfortably Under the Stars
As outdoor enthusiasts continue to explore the great outdoors, many seek lightweight, compact, and efficient gear for their adventures. One piece of equipment that has gained popularity in recent years is the bivy sack (short for “bivouac sack”). Bivy sacks offer a minimalist and lightweight alternative to traditional tents, providing shelter and protection from the elements in a compact package. In this article, we will explore the top bivy sacks available on the market today and help you choose the best one to suit your needs.
- The Best Bivy Sacks
- Types of Bivy Sacks
- Selecting the Right Amount of Insulation
- Bivy Materials
- Features to Look Out For
If you prefer not to carry a tent, a bivouac sack, commonly known as a bivy, is a compact alternative. It can be considered the smallest form of a tent before becoming just a sleeping bag. Bivies vary in size, with some being small enough for limited movement and others accommodating a sleeping pad and bag.
Backcountry adventurers and preppers often opt for bivies when they desire a lightweight and quick shelter option, without resorting to sleeping directly under the stars. However, experts generally recommend one- or two-person tents for primary go-bags, as they offer more space and advantages compared to bivies.
Bivies have limited space, often providing room only for essentials like a water bottle and shoes. Tents require more setup time, whereas certain bivies can be unrolled and placed on the ground effortlessly. Some bivies even feature a single tent pole to create additional headroom.
Bivies can fit into tight spots where tents may not, such as rocky areas or rough terrain. However, due to their waterproof nature, condensation can accumulate inside the bivy from breath and sweat. Material selection is crucial, and some models incorporate vents and flaps to minimize condensation issues.
There are also “emergency bivies” available, typically made of mylar, which serve as a lightweight and compact option for unexpected situations. However, these are more suitable as backup or temporary solutions rather than primary shelters.
- Most bivies weigh between 10 ounces and 1 pound 12 ounces, saving about 1-3 pounds compared to tents.
- Excluding single-use emergency types, recommended bivies can be compressed into a package measuring approximately 6″ x 12″.
- Bivies are rated as 2-, 3-, or 4-seasons, with 3-seasons being suitable for most people unless living in very northern regions.
- Even when choosing a bivy, it is still important to have a sleeping pad and sleeping bag.
- If a bivy is the main shelter in a bug out bag, carrying a tarp and cordage is advisable to complement its limitations.
- Synthetic sleeping bags are recommended with bivy sacks due to condensation issues, as they dry more efficiently and provide insulation even when wet.
- Bivy sacks offer better insulation than most tents due to the reduced air volume inside.
The Best Bivy Sacks
1. Outdoor Research Alpine Bivy
Outdoor Research’s Alpine Bivy is a favorite among backpackers and mountaineers and for a good reason. This bivy sack is made with Gore-Tex Respiration Positive fabric, which offers excellent breathability and waterproof protection. It also features a durable floor and a no-see-um mesh panel for bug protection and ventilation. The Alpine Bivy is lightweight at just 1.6 pounds and packs down small, making it an excellent choice for those looking to save space and weight in their pack.
2. MSR Pro Bivy
The MSR Pro Bivy is another top choice for those in search of a lightweight and packable shelter. Weighing just under one pound, this bivy sack is one of the lightest on the market. It features a breathable and waterproof AscentShell fabric and a wide-opening zipper, making it easy to enter and exit. The MSR Pro Bivy also includes a reinforced floor for added durability and a stuff sack for convenient storage.
3. Black Diamond Big Wall Hooped Bivy
Black Diamond’s Big Wall Hooped Bivy is designed with rock climbers and alpine adventurers in mind. This bivy sack features a single-pole design that creates extra headroom, allowing users to sit up comfortably inside. The durable ToddTex fabric offers excellent waterproofing and breathability, while the sewn-in flexible wire creates a vent for air circulation. The Big Wall Hooped Bivy is a bit heavier than other options on this list, but the added comfort and versatility make it a popular choice for extended adventures.
4. Rab Alpine Bivy
The Rab Alpine Bivy is an excellent option for those looking for a balance of weight, durability, and protection. Made from Rab’s own 3-layer waterproof and breathable fabric, the Alpine Bivy is both lightweight and durable. It features a wide zip opening with a storm flap for added weather protection and a mosquito net for bug-free nights. The Rab Alpine Bivy is a solid option for backpackers and alpine climbers alike.
5. SOL Escape Pro Bivy
For those on a budget, the SOL Escape Pro Bivy offers a more affordable option without sacrificing quality. This bivy sack is made with SOL’s proprietary Escape fabric, which reflects 90% of your body heat, making it perfect for colder nights. The fabric is also breathable, water-resistant, and windproof, providing excellent protection from the elements. The SOL Escape Pro Bivy is a great choice for those looking for a reliable and cost-effective shelter solution.
Best for Quality: REI Co-op Superlight Bivy
The REI Co-op Superlight Bivy provides high-quality features typically found in more expensive bivy sacks. Weighing only 1 pound 6 ounces, this 3-season bivy is constructed with waterproof and breathable Pertex nylon, featuring a ripstop nylon floor. It incorporates a clever design with tent poles that expand the bivy section around your face and chest, offering increased space and airflow. The inclusion of a mesh panel allows for stargazing while minimizing condensation and keeping bugs out. Additionally, the bivy includes corner guyouts for expansion and staking to the ground. With a price of approximately $150, the REI Co-op Superlight Bivy offers excellent value for its premium features.
Best for Premium Materials: Outdoor Research Interstellar Bivy
For those seeking a premium bivy, the Outdoor Research Interstellar Bivy is worth considering. Weighing in at just 1 pound 3.9 ounces, this bivy is crafted from Outdoor Research’s innovative AscentShell material, known for its breathability and waterproof properties. The same fabric is used in their renowned jackets and pants. The Interstellar is classified as a “3 to 4 season” tent, making it suitable for various weather conditions and seasons.
With a single pole, the shoulder area of the bivy expands, providing additional interior space. The bivy features a guyline loop on the exterior, allowing for the extension of the bivy like a conventional tent, and stake loops for securing it to the ground. The inclusion of a mesh face panel helps reduce condensation and keeps insects at bay. Priced at $275, the Interstellar Bivy is a premium product incorporating state-of-the-art materials.
While these models are not currently our top picks, they offer additional options for your consideration:
- Black Diamond Bipod Bivy
- MSR E-Bivy
- Outdoor Research Bug Bivy
- Outdoor Research Helium Bivy
- Outdoor Research Wilderness Cover Bivy
- REI Co-op All Season Bivy
- REI Co-op Shell Bivy
- REI Co-op Superlight Bivy
- Sierra Designs Backcountry Bivy
In addition, if you are looking for emergency bivy sacks as backup options or for your car, the following choices are available:
- Outdoor Research Helium Emergency Bivy
- Rab Survival Zone Lite Bivi
- SOL Emergency Bivy
- SOL Thermal Bivy
Types of Bivy Sacks
When it comes to bivies, there are four main types available in the market:
The most common type of bivy is a sleeping bag sack designed to fit you and your sleeping bag. It typically has a drawstring opening for breathing. These bivies are extremely convenient as you can simply place them on the ground and easily slide inside.
A bivy shelter is a type of bivy that includes tent poles, making the setup process slightly more involved. However, the advantage of a bivy shelter is that it keeps the bivy off your face. Instead of a face hole, it features a zip-open flap with a mesh covering, similar to a tent. The addition of tent poles also provides some extra space to store essential gear.
This particular variant of the bivy shelter is designed with a mesh covering. While it may not provide protection against the elements, it serves as a shield against mosquitoes and other insects. This type of bivy is ideal for summertime or warm, dry climates. In case of rain, you can improvise a rainfly by using a tarp.
These variations referred to as “bivies” are not traditional bivies as they don’t fully cover your body. Instead, they resemble single-use sleeping bags. Most of these models are constructed with mylar material, which helps retain body heat but can accumulate condensation. They are typically thin and not intended for frequent or intense use.
Emergency bivies are relatively inexpensive, with high-end options costing around $40. They are lightweight and compressible, making them a practical addition to your vehicle or get-home bag in case of a stranded situation. It’s important to note that emergency bivies are not designed for regular sleep but rather for emergency scenarios.
In addition to these, you may come across other innovative bivy designs in the market, such as bivies that serve as a dual-purpose poncho.
Selecting the Right Amount of Insulation
Bivies are available in 2, 3, and 4-season options:
- 2-season bivy sacks are suitable for mild summer weather but not recommended for windy or snowy conditions.
- A 3-season bivy can handle various weather conditions except for extreme wind and snow. These bivy sacks are lightweight and breathable, making them a popular choice for most people.
- 4-season bivy sacks are designed for extreme wind and snow. However, they can be too hot and heavy for regular use in non-extreme environments.
For most individuals, a 3-season bivy is the preferred choice. Even in colder settings, selecting a proper site and using a sleeping pad can help mitigate wind chill and keep you warm. 4-season bivies are more suitable for prolonged exposure to extreme conditions, but for most situations, a traditional tent is a better option.
The material used in a bivy is the most critical factor to consider. Since bivies have limited ventilation, it’s essential to choose a breathable fabric that allows moisture to escape while keeping external moisture out. High-quality materials such as Gore-Tex, ToddTex, eVent, and Pertex are known for their excellent breathability.
Bivy sacks usually consist of two to three layers of material, with the outer layer being the most water-resistant. Unless it’s specifically designed as a bug bivy, the opening of a bivy will typically have both a waterproof layer and a mesh layer. This design ensures protection against bugs while offering the option to open up for ventilation or enjoy a view of the night sky.
Features to Look Out For
Let’s explore some additional factors to consider when choosing a bivy or deciding between a bivy and a tent:
Contrary to expectations, a good quality bivy can be just as expensive as a tent or even more. The need for effective condensation management makes material selection crucial for bivies, which can impact their cost.
Opting for a bivy means sacrificing some comforts for the sake of portability. However, it’s worth noting that certain bivies can weigh as much as small tents. If you’re torn between a bivy and a tent, compare the weights of different bivy models with those of 1- or 2-person tents.
Ensure that the bivy’s dimensions accommodate your height comfortably. Also, consider the packed size of the bivy to determine how well it fits in your backpack, especially if you prefer a minimalist setup.
High-quality zippers, such as those produced by YKK, are indicators of well-made gear. Manufacturers that prioritize the quality of small yet essential components like zippers often produce excellent products.
While a bivy should have at least one zipper for entry and exit, it’s advantageous if it also features additional zippers for creating armholes. These armholes enable you to perform various camp tasks while remaining covered, such as cooking or organizing gear. More zippers also provide additional ventilation options.
Although you can seal the seams yourself to ensure waterproofing (similar to tents), it’s convenient if the bivy comes with pre-sealed seams from the factory, saving you the trouble.
Look for a bivy with 2-3 layers. The outer top layers should be constructed from a breathable waterproof material, while the underside should feature ripstop nylon. Ideally, the bivy should have a mesh net layer near your head and shoulders, positioned beneath a waterproof layer that can be zipped away, leaving only the mesh section exposed.
If you choose to carry a bivy as a shelter solution, here are some tips:
- Open your bivy near your face to allow your breath to escape the bivy, reducing condensation. Consider wearing a face wrap or balaclava to keep your face warm.
- Before entering the bivy, change into dry clothing if your current attire is wet or damp.
- When not in use, turn your bivy inside out to facilitate drying.
- Store essential gear inside the foot of your bivy sack to keep it secure and easily accessible in case of an emergency.
Choosing the best bivy sack for your outdoor adventures is a personal decision, as different individuals prioritize different features. However, this list provides a solid starting point for finding a bivy sack that suits your needs. Whether you’re an ultralight backpacker, a mountaineer, or a weekend warrior, a bivy sack is a great option to provide shelter and protection from the elements without the bulk and weight of a traditional tent.