Everything you need to know about Bivy Sacks

I have been camping for years, but admit I have never slept in a bivy sack. So hearing about bivy sacks i decided to perform research on everything you need to know about bivy sacks

After writing this article I am keen to try one out. Campers who use bivy sacks talk in a sense of excitement about getting closer to the wild. And about being able look up at the stars before you sleep.

Bivy’s are the ideal sleep companion for minimalist campers/trekkers.

Everything you need to know about Bivy Sacks

What is a Bivy Sack?

A bivouac sack or bivy sack as commonly known is a portable is a portable, lightweight, waterproof shelter which is super fast to set-up and use in small space.

Lighter than a tent a bivy sack is a choice for hikers or climbers wanting to be carry less weight, be minimalist, who have to camp in tight areas, or in unknown areas. 

Early on bivy sacks were a simple waterproof sleeping bag made from canvas, generally plagued with condensation issues inside the bag.

Thankfully Bivy’s have come along way.

Now-days bivy sacks made with light weight water proof materials and come with many useful features.

Why called a Bivy?

According to wikipedia, the reason being “A bivouac shelter is colloquially known as a bivvy (also spelled bivy or bivvi or bivi).

The word bivouac is French and ultimately derives from an 18th-century Swiss German usage of beiwacht (bei by, wacht watch or patrol)”.

So how does a bivy sack work? A bivy sack is a large thin waterproof insulated sack that simply slips over sleeping bag protecting it from getting wet and damp. Prior to falling asleep pull the cover over your head. 

The basic purpose of a bivy sack is to add a thin waterproof fabric over you in your sleeping bag to protect you while you sleep. It provides insulation and prevents wind chill and rain.

Photo Courtesy MSR Gear

How do you reduce Bivy Sack condensation? 

To reduce bivy Sack condensation, just leave a small gap for your mouth to breathe out of in order to minimise the condensation.

Not all bivy’s are equal. Some handle the minimisation of condensation than others. 

Are Bivy Sacks waterproof?

Most bivy sacks are waterproof, some more than others. Before you buy a bivy sack make sure you check product details and customer reviews.

Customers will soon scream out if the manufacturer of the bivy sack claims to be waterproof and isn’t.

Do you need a tarp with a Bivy Sack?

You don’t need a tarp for the bivy sack. However, a bivy sack can be quite stuffy and constraining (but warm and secure), so having a tarp can provide some relief by having your head or shoulders out of the bivy sack.

The downside is leaving your face and shoulders exposed to the elements and insects. Nothing worse than waking up to a face bitten all over by mosquitos. 

Does a Bivy Sack provide warmth?

Although insulated a bivy sack is colder than a tent so make sure to take warm clothes.

Photo Courtesy Outdoor Research

Is a Bivy Sack warmer than a tent?

Being small a bivy sack would have less space and air to heat up than a tent. However, in cold winds a tent offers more protection and can keep you warmer. 

Cold ground will transfer into your body, suggest sleeping a hiking mat to maintain your body warmth. 

Can you increase warmth of Bivy Sack?

It is possible to increase warmth of bivy sacks. Tips to increase warmth of bivy sacks below;

  • Placing a sleep mat underneath will improve comfort and warmth. 

  • Place hot water bottle inside your sleeping bag

  • Move to sheltered position away from cold winds

  • Thermal layering Upgrade to warmer rated sleeping bag

Do you need a sleeping bag in a Bivy Sack?

Yes, a bivy sack is waterproof so you can sleep in it. You will need a sleeping bag to keep yourself warm. 

Sleeping in a Bivy Sack safe?

Yes, sleeping a bivy sack is generally considered to be safe. However, you do need to take precautions on where your pitch for the night.

Don’t go to sleep in ditches or dry river beds, waking up in a cold water would not be fun.

Also, look up before pitching for the night. Tree branches and limbs have potential to fall down during the night.

How clean a Bivy Sack?

Best to use soft detergent and warm water, gently sponging down the bivy sack.

Never scrub, place in washing machine or use harsh chemicals. Otherwise, will shrink or damage the bivy sack. 

Popular Bivy Sacks in the market today

I have researched the most popular bivy sacks on the market today. Reviewing their reviews and customer testimonials have filtering the best bivy sacks.

Based on my research i would be confident buying either of these three bivy sacks

MSR Quick-Pitch Waterproof Pro Bivy Emergency Shelter

Price; $199

Weight; 8.9 oz

Pack size; 8″ x 3.5″

Poles; No


Waterproof; Yes


According to their website, the The MSR Quick-Pitch Waterproof Pro Bivy Emergency Shelter is a lightweight, breathable shelter designed for professional alpinists and serious adventurers

Made from durable water repellent (DWR) coating and Xtreme Shield waterproof coating lasting up to 3 times longer than standard coatings.

A super light weight, four season bivy sack at affordable price of $199

Outdoor Research Alpine Bivy

Price; $248

Weight; 20.7 oz

Pack size; 4″ x 15.5″

Poles; Yes


Waterproof; Yes


Made with top quality materials the Alpine is ultra-capable in cold and wet environments.

A true four-season bivy. Keep rain and snow out while letting internal moisture escape

Considering the constraints of a bivy sack, the Outdoor Research Alpine Bivy provides ample room and comfort.

 The unit allows blocks outside weather while allowing moist air to escape, minimizing any condensation.

If you are looking for a four-season bivy sack Outdoor Research Alpine Bivy must be considered.

REI Co-op Superlight

Price; $149

Weight; 24.8 oz

Pack size; 5 x 12″

Poles; Yes


Waterproof; Yes


The REI Co-op Superlight bivy could easily be mistaken for a swag, mini single person tent, or something in between.

According to the reviews, this bivy is a lightweight, warm, and affordable sleeping unit. It is one of the most functional and comfortable bivys on the marketplace,

The affordable price of $149 is worth serious consideration.

Final Thoughts

Now I have written this article on everything you need to know about bivy sacks I am off to purchase one of the three products recommended above.

If you are looking to purchase a bivy sack check customer reviews to ensure the bivy is in fact waterproof and prevents condensation from forming.

More Information

If you have enjoyed this review, you will enjoy our other reviews.

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