A Guide to Bivy Bags & Bivy Sacks

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Bivy bags were developed many years ago as single-person shelters.

Originally, bivy bags were little more than a waterproof sleeping bag, used primarily by ultralight backpackers, mountaineers, climbers and those requiring an emergency shelter from the elements.

In recent years, bivy bags have evolved massively, to the point where they are able to incorporate mesh screens and certain high-tech breathable fabrics such as Gore-Tex (among other things).

What is a Bivy Bag?

A bivy bag (also known as a bivi bag, bivvy bag, bivouac, bivie or bivy sack) is compact, lightweight alternative to a tent.

Bivi bags are a waterproof, wind resistant shell that will fit a sleeping bag inside (meaning you can sleep inside them whilst protecting yourself from the wind and rain).

They’re like an extra layer of armor for your sleeping bag, and make sleeping outside without a tent a possibility.

As well as offering protection from the elements, a good bivy sack with provide additional insulation and warmth.

In essence, bivy bags are designed to perform two basic functions: To keep your sleeping bag dry (which is placed inside it) and to provide some extra insulation/warmth.

Most good bivy bags are made from a material called Gore-Tex. This makes them highly breathable and goes a long way to stopping condensation from building up inside the bag (which isn’t nice if you’re sleeping inside of it!)

In theory, a bivvy sack can shield you from cold weather, heavy rain storms and wet ground left behind as a result. Whether a bivy sack can actually do this or not largely depends on the quality of the bag (i.e. the materials it’s made from and the craftsmanship).

Bivy Bag

Who Are Bivy Sacks For?

Although anyone can use a bivy bag, they’re primarily designed for people who:

  • Want to make their backpack as light as possible (by ditching their tent).
  • Climb up rock faces/mountains that take more than one day to scale.
  • Don’t mind sleeping in a tight, cocoon-like space.

Bivvies work great when you’re climbing, as they’re much easier to set up then a tent (and they take up less space).

They’re also used extensively by the lightweight backpacking community (i.e. people who are obsessed with shedding every possible ounce of weight from their backpack).

Bivy Shelters

Bivy ShelterI briefly mentioned early how bivy sacks have evolved recently. One such fruit of this evolutionary tree has been the bivy shelter – a cross between a bivy bag and a low-rise tent.

Unlike bivvy bags, bivy shelters are often suspended at the head opening (using either poles or hoops) and have an attached mesh panel.

This suspended mesh above your head allows you to have a fully enclosed canopy (protecting you from bugs) whilst allowing in light and fresh air.

Buying a Bivy Sack

As with most things in life, the more you pay for a bivy bag, the better quality you’ll get. If you choose to buy the cheapest one around, don’t expect it to handle a torrential downpour with any great ease.

How good your bivy sack needs to be largely depends on what you’re going to be using it for. If you’re climbing a mountain and you could be encountering some potentially difficult/dangerous conditions, it’s important that you stay dry and warm no-matter what as you’ll be a long way from home.

In cases like this it’s worth spending some extra money to buy a bivy bag that’ll properly keep the rain out, keep you warm and that won’t let condensation build up inside (thus getting you wet).

The biggest problem that most people have with bivvy bags is that they find condensation building up on the inside.

To avoid this from happening to you, look for bivy sacks made from breathable materials (such as Gore-Tex).

Additional Features to Consideration
When buying a bivy bag, you might also want to consider these additional features:

  • A zipper that runs down the length of the bag, allowing you to open it up for more ventilation.
  • Arm-holes on the side, allowing you to do things outside your bag (such as sort out your gear) from inside your bag.
  • Straps to keep you in place as you sleep.

Bivy bags aren’t for everyone, as some people might shiver at the thought of spending a night in one.

That being said bivy bags are a great (not to mention lightweight) sleeping solution, as they’ll save you having to carry around a tent, making your backpack lighter in the progress (or giving you more room to carry other things).

Related posts:

  1. A Buyer’s Guide to Laptop Bags
  2. How to Buy a Cold Weather Sleeping Bag
  3. How to Clean (and Care for) Your Sleeping Bag
  4. Airport Rules for Carry-on Bags
  5. Buying an Ultralight Sleeping Bag

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