How to Reduce Condensation in a Tent

by wheretheroadforks

Condensation inside of a tent is an annoyance that every camper faces. It is an unavoidable natural process that occurs in every tent, regardless of the design and the materials it is made of. You can’t stop condensation but you can minimize it by taking a few simple precautions. This guide outlines how to reduce condensation in a tent. I’ll talk about campsite and gear selection, ventilation, moisture reduction, and more.

three tents in the mountains

What Causes Condensation in a Tent?

Condensation occurs when warm, humid air contacts a cold surface. The air inside of your tent is warmed by your body heat and your breath as you exhale. That warm air rises until it hits the fabric of your tent. The tent fabric is cooler because the air outside is cooler. When the warm air meets the cool tent, moisture in the air condenses and turns to liquid water.

This is the same process that causes water droplets to form on a cold bottle of beer on a hot day. When warm air hits the cold bottle, the water vapor in the air condenses on the bottle and makes it wet. Another example is your bathroom mirror fogging up while you shower. The warm steamy air hits the cold mirror and condensation occurs. The water changes state from a gas to a liquid.

condensation forming on a glass of ice water
Condensation on a glass of ice water

Over the course of the night, condensation collects on the inside of your tent until the fabric becomes saturated. At this point, the water may begin to drip down onto you and your sleeping bag.

How to Reduce Condensation Inside Your Tent

The amount of condensation that you experience depends on a number of factors including the level of humidity in the air, your campsite location, the gear you’re using, and the amount of moisture that you bring into the tent. There are three main strategies for reducing tent condensation. You’ll want to use all three to stay as dry as possible.

tents pitched on a hillside

1. Choose the Right Campsite

When selecting a campsite, look for the warmest and driest spot you can find. When your tent walls are warmer, less condensation occurs. If the air is dry, there is less moisture available to condense. A few campsite selection tips include:

  • Avoid setting up camp in a low spot in the landscape- The reason is that heat rises and pushes cold air down into low points. When your tent walls are cold, condensation is worse because the difference in temperature between the inside and outside is greater. Look for a campsite that is raised up a bit. Your tent walls will stay slightly warmer and you’ll experience less condensation. Raised sites also tend to have a little breeze which can help with ventilation. By camping on higher ground, you also eliminate the risk of waking up in a puddle if it rains in the night.
  • Avoid camping near water sources- Humidity levels are higher near lakes, streams, and rivers as well as marshy areas. The reason is that water evaporates from the water sources into the air and increases the level of humidity. More moisture in the air means more condensation.
  • Camp under trees- Air under trees stays slightly warmer than air in a large open field. This helps to keep your tent fabric slightly warmer. Additionally, water vapor in the air will condense on the trees instead of your tent. This helps to prevent the outside of your rainfly from becoming saturated.
  • Avoid camping on wet ground- If the ground feels squishy when you walk, look for another spot. Water on the ground can evaporate in the night and increase the humidity around your tent. Some water vapor can evaporate up into your tent’s rainfly. This adds moisture which increases condensation.
Good campsite selection
Good campsite selection

2. Improve Ventilation

Your breath and sweat make the air inside of your tent get humid quickly. Ventilation replaces the moist interior air with drier outside air. The less moisture in the tent, the less condensation you’ll experience. A few tips to improve tent ventilation include:

  • Stake the tent out in a way that maximizes the space between the rainfly and tent inner- This is only possible on double wall tents. You want to allow as much air as possible to pass between the mesh inner and rainfly as well as the rainfly and the ground on the sides. If you’re using a single wall tent, stake the tent tautly so that the mesh sections are held open and not sagging. You want to allow as much air to pass through as possible. This way, dryer fresh air will enter and humid interior air will leave.
  • Open all doors, windows, and vents- If it’s not raining, open your tent up as much as possible to maximize cross ventilation and to allow your humid breath to escape as you exhale. Most tents at least have a couple of vents that prop open. Larger tents have windows with roll-up sections. Only close them if it starts to rain. Of course, you want to leave the mesh section in place to keep the bugs out. Also, make sure your gear isn’t blocking any of the vents.
  • Leave the vestibule open- This allows more air to pass between the rainfly and tent inner. It also allows fresh air to flow into the tent through the main door if you leave it open. Of course, you’ll want to close the vestibule if it starts to rain.
  • If there is a breeze, position your tent so a door or window faces into it- The breeze will blow through your tent and replace the humid air inside with fresh drier air from the outside.
  • Don’t use the rainfly if you don’t expect rain- If you’re using a double wall tent, you can nearly eliminate condensation by sleeping without the rainfly. Moisture will just evaporate away. Of course, you’ll want to check the weather forecast and make sure the sky is clear so you don’t get rained on in the night.
a tent without a rainfly
Sleeping without the rainfly is the best way to improve ventilation

3. Minimize Moisture Inside the Tent

The more moisture and humidity that you bring into your tent, the more condensation you’ll experience. Moisture inside of your tent comes from three sources:

  1. The air in the environment- Moisture in the air is called humidity. You can’t control this. Before your trip, you may want to look into the humidity of the region where you plan to camp. This info can help you select the right shelter and sleep system for your trip. Some camping shelters deal with humidity better than others. More on that in the next section.
  2. Your breathing and sweating- While you sleep, you exhale moisture into your tent with every breath. You also sweat in your sleeping bag. I have read figure clamming that you loose around 1 liter of water per night but couldn’t find a reliable source for this info. Regardless, these natural functions add moisture to the inside of your tent which increases condensation.
  3. Wet items you brought inside of your tent- Having wet items in your tent increases the moisture level. This is one thing you have full control of.

A few ways to minimize moisture in your tent include:

  • Remove wet items like your clothing, boots, socks, and your pack from the tent- Store any wet items outside if it’s not raining or in a dry sack if it is raining. You can store them under your vestibule but this isn’t ideal as the moisture can still evaporate and condense on your rainfly.
  • Avoid sweating too much inside of your tent- Sweat increases the humidity inside of the tent. Before climbing into bed at night, wait for your body to cool off, stop sweating, and dry off if possible. This is important if you’ve been active right before bed. Use a sleeping bag or quilt with the proper warmth rating for the environment you’re camping in. This way, you don’t get too hot and begin sweating in the night. If you start sweating, unzip your sleeping bag or open it up a bit so you can cool down.
  • Breathe out into the open, not into your sleeping bag- If you breathe into your sleeping bag, it will get damp because the moisture can’t escape. Try to breathe out in the open so the moisture that comes from your breath can vent away. Ideally, position yourself so you’re breathing near the door or window so the moist air can easily escape.
  • Don’t cook under your vestibule or eat inside your tent- Steam from cooking and eating hot foods increases the moisture level inside of your tent. Eating also increases body temperature which can make you sweat.
  • Dry your tent and sleeping bag out during the day- In most climates, condensation will make your tent and gear damp during the night, no matter how careful you are. There is no avoiding it. If you don’t dry your gear out, the moisture keeps building up every night. Over the course of multiple days, your gear can get soaked. When you have the chance, lay your tent, sleeping bag, clothing, and any wet items out in the sun so they can dry. That way, you’re starting with a fresh and dry shelter at night.
  • Use a footprint under your tent- Even though your tent floor is waterproof, water can seep through in the night if the ground is wet enough or if a puddle forms under your tent. Once the water gets in, it can evaporate and condense on the ceiling. A tent footprint gives your tent floor an extra layer of protection.
  • Don’t let your dog sleep in the tent with you- Dogs breathe and exhale moisture just like you. They also sweat and pant to get rid of excess heat. This introduces more moisture into your tent, which means more condensation. Of course, if it’s cold or raining outside, you’ll want your dog to stay warm and comfortable. If you want your dog to sleep inside with you, pack a larger tent with better ventilation. Larger tents that are made for multiple people can handle more moisture.
Leave your wet gear outside to avoid bringing moisture in

Environments Where Condensation is a Problem

Condensation isn’t a problem in every climate. The weather conditions need to be right. Generally, you don’t have to worry as much about condensation when camping in deserts, arid regions, and dry mountain regions. These places typically have low humidity. There isn’t much moisture in the air to condense.

In areas where humidity is higher, condensation is more of a problem. Examples include rainy regions, the tropics, near bodies of water, low points like valleys, and marshy areas. Condensation can also get bad in cold climates because the temperature difference between the outside and inside of the tent is so great. If the weather is below freezing, the condensation can turn to frost on the inside of your tent.

Choosing the Right Tent to Avoid Condensation

Some tents perform better than others in high condensation environments. There is no perfect tent for all weather conditions and seasons. Before your trip, consider the climate where you’ll be camping. Tents come in single and double wall designs as well as freestanding and non-freestanding. All tent designs have advantages and disadvantages that are worth considering.

Double wall tents deal with condensation better than single wall tents. The reason is that double wall tents allow condensation to pass through the mesh inner and collect on the rainfly instead. When the condensation builds up, it rolls down the inside of the rainfly and onto the ground. When your gear rubs up against the inside of your tent’s mesh inner, it stays dry because it will hit the dry mesh instead of the wet rainfly. Condensation isn’t eliminated but is kept away from your gear. You can also use double wall tents without the rainfly, which does greatly reduce condensation because ventilation is greatly improved.

Single wall tents are lighter but tend to trap more humidity inside. This results in more condensation. The reason is that single wall tents typically don’t vent quite as well. They have less mesh and fewer vents. Because they are single wall, condensation collects directly on the tent fabric. When your gear rubs up against it, it gets wet.

Single wall non-freestanding tent
A single wall non-freestanding tent

Whether you go with a single wall or double wall tent, choose one that offers the maximum amount of ventilation. You want a lot of mesh and doors and windows to allow air to pass through.

A Note About Hammocks, Tarps, and Bivy Sacks and Avoiding Condensation

Sometimes a tent isn’t your best camping shelter option. If you’re camping in a hot and humid environment, like the tropics, you might want to consider using a hammock. These breathe incredibly well because they are open. You can also pair a hammock with a bug net and tarp to keep mosquitoes and rain out. Check out my hammock vs tent guide for more info.

camping in a hammock
Hammock camping

Camping tarps also make an excellent alternative to a tent. Because they don’t have walls, they breathe incredibly well. They also keep you cooler because they don’t trap as much heat. You’ll probably want to pair your tarp with a bug net and groundsheet to keep the bugs out and stay a bit drier. When pitching your tarp, try to set it 6-18″ off the ground so there is plenty of room for air to pass through between the ground and the tarp. For more info, check out my tarp vs tent guide.

Bivy sacks are probably the worst shelter option for camping in a high condensation environment. The reason is that they don’t ventilate very well. This is true for a number of reasons. First, bivys are small. This means humidity builds up inside fast. The material also plays a role. Most bivys are made of waterproof breathable materials like Gore-Tex. These don’t ventilate nearly as well as mesh. Because the bivy material lays on the top of you, your sleeping bag tends to get wet when water condenses inside. If you choose to use a bivy in a humid climate, you’ll want to air both the bivy and your sleeping bag out daily so too much moisture doesn’t buildup

Choosing the Right Sleeping Bag to Avoid Condensation

Some sleep systems are better suited for humid environments than others. If you expect condensation to be an issue, consider using a synthetic sleeping bag or quilt instead of down-filled. Synthetic insulation can keep you warm, even when it gets damp. Down loses its insulation property if it gets wet. This happens because the down clumps together when wet so there are fewer air pockets to trap heat. Synthetics maintain more loft and stay warmer. For more info, check out my guide to down vs synthetic insulation.

Also, try to choose a sleeping bag that offers some kind of DWR (durable water repellent) treatment. This chemical treatment makes the outer fabric repel water which helps to protect your bag’s insulation from getting wet. When the bag gets wet, water rolls off instead of being absorbed. This will help your sleeping bag stay dry and keep you warm, even if some condensation drips on it. Of course, the DWR can only do so much. The bag can still get wet if condensation gets too bad.

You also want to choose a sleeping bag that has the appropriate warmth rating for the environment you’re camping in. If you get too warm in the night, you’ll begin to sweat. This sweat increases the humidity in your tent which increases condensation.

If your sleeping bag does get damp in the night, the best solution is to lay it out in the sun or hang it in a breezy spot while you’re packing up camp in the morning or during a rest break during the day. If it’s raining, take advantage of any clearing in the clouds. Sleeping bags are made of quick-drying fabrics. Under direct sunlight, your sleeping bag should dry in 5-15 minutes depending on how wet it is.

sleeping bags in a tent

Tip: Consider choosing a dark-colored sleeping bag. Black is ideal. The reason is that dark colors absorb more wavelengths of light and convert them to heat. The material heats up faster. This property allows your dark-colored sleeping bag to dry out slightly faster than a light-colored sleeping bag.

A Note About Camping in the Rain

When it’s raining, condensation gets worse. The reason is that the relative humidity increases because the rain that has fallen begins to evaporate back into the air. This water vapor cools the air and increases the total amount of moisture in the air. When it’s raining, you’ll almost certainly experience condensation in your tent.

The best thing you can do is to pitch your tent taught. If your tent is double wall, pitch the rainfly so it stretches as far from the tent inner as possible. This usually means staking it out separately from the tent inner. This allows the maximum amount of airflow. Because the rainfly sits away from the tent, water that condenses on the inside of the rainfly will hopefully roll down onto the ground instead of drip on you. If your tent is single wall, pitching it taught helps to hold the vents open, which improves airflow.

If the condensation gets too bad, your best option is to wipe away the water droplets on the inside of your tent before they begin dripping down onto you and your gear. Simply use a towel, bandana, or a sock to wipe off any excess water that you can. If the conditions are just right, you may need to do this every few hours.

Packing Up a Wet Tent and Sleeping Bag

In the morning, your tent will likely be a bit wet. The top might be covered in dew and the inside will probably have a bit of condensation. If it rained during the night, shake the tent off to remove the majority of the water. Try to lay your tent out in the sun and let it dry. If you have a freestanding tent, leave it pitched and move it to a sunny place. Fabrics used to make tents dry quickly. Under direct sunlight, your tent should be dry in 10-20 minutes.

If you’re in a hurry, you can simply shake any excess water off of your tent or wipe your tent down with your camp towel or bandana before packing it up. This will remove most of the excess water. Store your wet tent away from your dry gear. I usually strap mine to the outside of my pack.

tent strapped to backpack
My tent strapped to the outside of my backpack

If you’re packing up camp in the rain, you just have to put your tent away wet. There is no alternative. If it stops raining and the sun comes out later in the day, you may want to take a break and lay your tent out in the sun to dry so it’s not soaking wet when you pitch it that night.

If you don’t get the opportunity to dry your tent during the day, you’ll just have to pitch it wet. This doesn’t cause any damage to the tent. It’s just an annoyance for you. If you can, set up camp a bit early in the evening so your tent has a chance to dry off. On a warm summer night, your tent may dry off before you’re ready for bed.

What to do When you Get Home

Chances are, your tent and sleeping bag will be a bit damp from condensation when you return home. Particularly if you’ve been camping for a few days. Before putting them away for long term storage, be sure to dry them out completely. Just lay them out in the sun for a few hours until they dry.

If it’s damp outside, you can dry them in your home as well. This increases the humidity in your house which isn’t ideal. Using a dehumidifier in the room where you’re drying your gear can keep your house dry and helps your gear dry out quicker. You can also put your sleeping bag in the dryer for a few minutes.

If you put a tent or sleeping bag away while it’s still wet, it will begin to mold after just a few days. If you don’t catch the mold in time, it can destroy your gear. Mold can make stains and smells that are impossible to get out. If the mold gets too bad, it can be hazardous to your health. Be sure to dry your gear completely before you store it.

A Note About Leaky Tents

It is possible to mistake a leak for condensation. To test whether your tent has a leak, pitch it in your back yard as if you’re expecting a rainstorm. Make sure everything is staked out properly. Spray the tent down with your garden hose to see if any water gets in. If it does, you probably have a leak.

If you find a hole or tear, you can patch it up to prevent water from leaking in. The easiest solution I have found is Gear Aid Tenacious Tape Fabric and Vinyl Repair. This stuff just sticks on like regular tape. It is waterproof and easy to install.

If a seam is leaking, you may have to use some sealant. I like Gear Aid Seam Grip WP. You just paint this stuff on with the included brush and it cures into a rubbery waterproof material that keeps water out.

Tent on the beach

Final Thoughts About Reducing Condensation in a Tent

Dealing with condensation is just a part of camping. If you choose the right campsite, properly ventilate your tent, and minimize the moisture you bring into your tent, you can greatly reduce condensation. Hopefully, this guide helps you stay a bit more dry and comfortable while camping in the backwoods.

Do you have any tips to help reduce condensation in your tent? Share them in the comments below!

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