Taking Care of Condensation in a Bivy Sack

If you have actually invested any kind of amount of time in a bivy sack that wasn’t particularly breathable, then you know all too well how awkward and bothersome condensation inside the sack can get. A lot of us spend means too long simply presuming that this is just one of the inevitable facets of backpacking life. Let go of this idea and also keep reading to learn Dealing with Condensation in a Bivy Sack

One of the advantages of using a bivy sack is that much of the condensation which would have otherwise occurred inside your sleeping bag or quilt instead will occur on the outer shell of the sleeping bag, or on one or both surfaces of the bivy sack’s upper shell fabric. This allows for the isolation of your sleeping bag from the condensed moisture. Before packing your sleeping bag and bivy sack, shake off any external condensation or wipe it off with an absorbent cloth. To prevent any moisture remaining in the bivy sack from wicking back into bag’s insulation, be sure to pack the bag and bivy sack separately.

dealing with condensation in a bivy sack


What Causes Condensation?

Condensation forms when humid air encounters a colder surface like the interior walls or roof of your tent. It’s the same process that occurs when you take a hot shower and the steam makes your bathroom mirror wet. Steam, which is simply water vapor in a gaseous form, is cooled when it hits the mirror, converting it to liquid water droplets that cover the mirror with moisture.

Winter and also the Humidity

Cold evenings are typically what produce our feared moisture problems. In cold climates, or in areas where the temperatures considerably drop at nighttime, it is common for the dew point and also temperature to reach the exact same level while you’re trying to sleep. To learn more about humidity, check out this Online Science write-up on the topic.

When this happens, dampness can start to easily collect along awesome surface areas, consisting of inside your sanctuary. condensation will start to line the inside of the textile, and soon sufficient will certainly have gathered to cause awkward dampness. As this cools, your sanctuary can begin to shed its heat, convenience, and effectiveness.


One of the biggest causes of this wetness comes from your own breath. As you exhale, the air you take a breath out is significantly warmer than the sanctuary product which is being cooled by the chilly evening air. Wetness from your breath will start to accumulate inside your sanctuary throughout the evening.

Sweating Via the Night

Furthermore, your body’s rising and fall temperature level can create the exact same issues. Even though you might get in cold, throughout the evening your body will naturally warm up and start to sweat. This wetness, like your breath, can start to condensate also. In some cases, this will not be as well recognizable or unpleasant to begin with but will slowly enhance the dampness as well as weight of your bivy sack in time.


It is much less usual for these concerns to occur in substantially warmer atmospheres unless those atmospheres are specifically damp. If the product of your sanctuary is cozy instead of trendy, after that it will not gather dampness. Nonetheless, the all-natural wetness in the air when it’s humid could provide similar troubles.

Just how Do I Lower Condensation?

The amount of condensation you experience is a tent is a function the humidity in the air around you and the moist air you expel from your lungs when you exhale. In order to reduce the amount of condensation that forms in your tent at night, you should:

Breath Outside

To reduce humidity inside your shelter, you have to decrease the quantity of moisture that obtains released on the inside in the first place.

One method of doing this is to prevent exhaling inside your bivy sack. Copulating your head outside is the most obvious means of doing this, but often exceptionally chilly temperatures do not permit this. In situations similar to this, merely unzipping one small opening near your head/face can do marvels. It enables the dampness from your breath to escape completely, instead of gather within.

Use Fewer Layers at Night

Secondly, you can wear less layers when you go to sleep in the evening. While we commonly layer approximately remain warm, this can really be counterproductive. Way too many layers will boost your likelihood of sweating, which is permitted to collect in the type of condensation can decrease the temperature level of the material. Rather, select one cozy layer of thermals in the evening.

Allow It Breath

In time, this dampness can make the material and also internal environment heavy, damp, chilly, as well as uneasy. This just intensifies the longer you let condensation accumulate. A terrific idea for preventing these points is to regularly broadcast out your bivy sack. We suggest unzipping and hanging it up each early morning to let it take a breath. Keep any perspiring garments from treking outside of the bivy.

Furthermore, selecting a design that is created with breathable and also well-ventilated materials before you also leave for your experience can go a lengthy way in avoiding condensation. Take A Look At Outdoor Equipment Laboratory’s referrals for some high-quality choices.

What if it’s raining?

If it’s raining, your chance of experiencing tent condensation will increase because there’s more humidity in the air. It’s a lot like camping next to a stream or a pond, but many times worse. If you have a single-wall tent or shelter, your best bet is to carry a small camp towel or bandana that you can use to wipe away any tent condensation before it drips onto your gear.

How significant is moisture in your breath?

When you sleep at night, you exhale about 1 liter of moisture. You’re not aware of it, but its one of the reasons why you wake up thirsty at night or in the morning. If there are 2 people in the tent, then you have to deal with 2 liters of tent condensation, and so on, as you add more people.


We wish you’ve discovered some useful information on exactly how to maintain Dealing with Condensation in a Bivy Sack. Bid farewell to condensation by lowering the interior wetness and constantly make sure to air it out in the early morning!

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