How to Prevent Condensation in a Tent
Camping in the great outdoors can be a remarkably cathartic and freeing experience. It can also be a real struggle. Some campers have had the misfortune of cozily drifting off to sleep in their dry warm tents only to wake up covered in cold water. Although leaks are often the culprit for this, condensation is also a major source of moisture under the right conditions.
Thankfully, this is something you can prepare for. Don’t let condensation invade your home away from home. Learning how to prevent condensation in a tent is a key camping skill that will have you sleeping drier and more comfortable for years to come.
What’s causing condensation in the tent?
Whenever warm humid air comes into contact with a cooler surface condensation occurs. The warmer gaseous water vapor in the air is slowed and condensed by anything cooler and this results in water droplets forming. This is exactly what happens to the outside of a cold beer on a warm day and it happens on the mirror in your bathroom if you take a hot shower. This is also what can happen to your tent.
If the inside of your tent is warmer than the outside, as happens when you are inside it and giving off all that body heat, then the walls of the tent and the rainfly become much cooler by comparison. This creates a nice little cold surface for moisture to build up and condensation to occur. Just add a source of warm water vapor and voila! Condensation will occur on the bottom side of your rainfly and then slowly make its way into your tent. This is not how you want to wake up in the morning.
This warm water vapor can’t really be avoided either. Your breathing alone contributes around 1-liter of moisture when you exhale in your sleep. There are several other sources as well and although you can’t get by too far without breathing you can definitely control the other factors adding to the condensation in your tent.
Ventilation is the key
Proper ventilation is your best friend when it comes to reducing the condensation in your tent. The blast of warm air you get upon returning to your tent and opening it in the evening is a result of humidity. The insides of tents are typically more humid than the outside but you want to avoid this as much as possible if you’re goal is to minimize condensation. Humidity is just water vapor in the air and that water vapor is just waiting to condense on a cooler surface as night falls, that cooler surface can be your tent.
Other sources of water vapor such as your breathing, nearby water, or even wet camping gear all add up quickly. Ventilation reduces the impact. Proper ventilation starts with tent placement. You want to position your tent so that the door is facing into any breezes or prevailing winds. This fresher and dryer air should be coming at you. This airflow will both reduce humidity around the tent and will also help pull water vapor away as it begins to condense on the rainfly.
The rainfly itself should be staked out tautly so that there is plenty of space between the fly and the wall of the tent. Of course, you don’t want so much space that rain can just come between the fly and the tent but you need enough so there is airflow and minimal contact between the two. Since condensation typically forms on the rainfly and then soaks into the tent wall any space between them will reduce that transfer and keep things drier for you inside.
Also, all the tent and rainfly doors and vents should be left open as much as possible. This is especially important for vents that are directly across from each other. This will create airflow in the tent and will create cross ventilation as well. That will, in turn, keep the inside of the tent cooler and dryer. Opening the tent windows is also important to achieve this same effect. Ventilation and airflow are dependent on tent placement and having enough openings for the air to move. When this is done correctly it can drastically reduce condensation.
Proper tent placement and setup is very important
Tent ventilation is the most important consideration for reducing condensation in your tent but tent placement and setup is an extremely close second. In some respects, they go hand in hand. As mentioned previously it is important to place your tent door facing into any breeze or prevailing wind because this aids ventilation. Other tricks provide similar benefits.
Because humidity is such a contributing factor to condensation it is important to set up and place your tent with that in mind. This means you should not place your tent close to any water sources. This includes lakes, ponds, rivers, streams marshes, and any other wet high humidity environments. This may seem counterintuitive at first but, when camping, it is better to have a short walk between you and the water. This will also reduce your run-in with bugs and wildlife which breed and feed by the water.
On that same note, you also have to consider ground moisture. Some places might not seem like a high condensation risk wet spot when they secretly are. A beautiful lush green grassy opening in a forest is probably also a spot with high ground moisture. It is the water in the soil which keeps the grass so vibrant and the flowers so plucky.
As nice as it might seem to camp there it isn’t the best spot. Instead, you should look for spots with little vegetation on the ground. Then, before placing your tent down, you should place a groundsheet or tarp which acts as a barrier between any ground moisture and you!
Stay high and stay dry
Once away from any water sources you should then look for higher tree-covered ground. This will be your ideal camping spot. A slightly higher elevation has many benefits. For one, cold air likes to pool in low areas and when this cold air meets your warm humid tent you get condensation. These low areas also have higher ground moisture due to lower airflow carrying it away.
Stay high and stay dry. Higher ground and drier camping also go hand in hand when it rains. The rain will pool in the low spots and, ideally, away from you. This should also reduce humidity and the number of bugs assaulting your campsite. The higher elevation also exposes you to more crosswinds which help with ventilation. High ground is a win-win-win when you’re camping.
Finding that high ground with good tree cover is also important. The trees can act as a natural rainfly and they will even collect condensation. The trees also help trap warmer air and this, in turn, should warm your rainfly and reduce condensation. Too many trees can block good airflow though which reduces ventilation and increases ground moisture. This is a bit of a balancing act.
The ideal spot for tent setup has little vegetation, low ground moisture, no nearby water source, decent land elevation, a nice cross breeze, and some tree cover. If you have to prioritize among these then staying away from a water source and finding a good cross breeze is the most essential.
Are you causing the condensation in your tent?
You will always contribute a little to the condensation in your tent with your breathing but that’s just unavoidable. The more people who share the tent the more this is a problem. Still, there are other things you might be doing which can really add to the condensation issue. Remember, the rule is that anything which adds moisture to the warm air inside the tent will, in turn, add to condensation.
This means that at the end of a day hike where you got drenched in the rain or fell in the river and all your clothes got soaked you should not bring all that wetness into the tent. Be one with nature, strip down, and leave any wet clothes or boots outside to dry. If you feel you absolutely must bring them into the tent then you should put all the wet things into a well-sealed bag to prevent condensation.
Some of this might seem self-explanatory but, when it comes to camping, a good reminder can’t hurt. Another major source of condensation occurs when campers decide to cook inside their tents. This is a bad idea plain and simple. Not only can the boiling water cause condensation to occur but cooking with any kind of heat inside a small space made of flammable material is never a good idea. Yes, tents are made to be flame retardant but that does not make them fireproof.
If you’re lucky enough to be camping with your four-footed best friend then keep in mind that they too can be a source of condensation. Unless you don’t mind the condensation and the mess caused by a wet dog your furry companion should be kept outside until they are fully dry. Anything you can think of which might significantly introduce water vapor to the interior of your tent deserves to stay outside until it has dried.
Some tips for dealing with the condensation that does occur
As we have covered, because you breathe you will create water vapor and this will cause some condensation in your tent. Also, camping isn’t always perfect and you can’t control all the conditions. The best you can do is minimize condensation and manage it when it does happen. Applying all the tips and tricks mentioned in this article, when possible, will go a very long way towards reducing the dampness you experience. For whatever remains you can be prepared.
The tools you will want are a microfiber towel and some plastic bags. A microfiber towel specifically is best for camping because they absorb tons of moisture and they can dry quickly. You can easily give the inside and outside of your tent a wipe down with a handheld towel, dry it during the day, and have it at the ready again. They are great!
The plastic bags are perfect for storing anything you don’t want getting wet or damp. This might include journals, books, and electronics. Your hiking backpack and your sleeping bag should both have waterproof layering built-in.
What type of tent is best to prevent condensation?
Tents can come in many different forms and sizes. Almost all of them can be divided into two categories though. You have your single-walled, or single-skin, tents and you have your double-walled, or double skin, tents. The single-walled tents are made of a single layer of breathable fabric which helps with ventilation.
These tents are usually cheaper, roomier and lighter weight but they are also less rugged and more susceptible to condensation. Their single breathable layer is also permeable to moisture under the right conditions. If condensation is expected to be an issue you do not want one of these tents.
The double-walled tents provide much better protection from rain and condensation. These are composed of a mesh inner tent and a waterproof outer tent called a flysheet. The space between these two sheets provides insulation and helps reduce condensation.
These double-wall tents are heavier and more expensive typically but they pay tremendous dividends if you expect to be in more extreme weather conditions. Try spending the night in a single-walled versus a double-walled tent during a bad thunderstorm and you’ll quickly experience the difference. You’ll notice a difference in moisture from condensation.
What else should I look for in a tent?
A double-walled tent is your best bet for reducing moisture from condensation but there are other factors to consider when generally thinking about keeping the inside of your tent dry. One of the key terms to consider is hydrostatic head (HH). This basically how waterproof the material of the tent is. Basic tents will start around 2000 mm HH and go up from there, the higher the better.
You also need to check the construction of the tent. Condensation is the least of your worries if a light rainfall floods your sleeping area. First, check the seams of the tent. The stitching should have a waterproof coating on it to prevent leaks. While you’re at it make sure the stitching is strong and uniform. Tents which use less stitching or overlap more of the material are better protected.
You should also check the zippers for fabric or plastic covers that block or redirect rain. These are very important. The overall construction of the tent has dozens of little ways to keep the inside dry and the water out. For example, a tent with a sewn-in bathtub groundsheet is a great investment. These tents basically have a thick layer of waterproof material sewn to the bottom and up the sides of the tent. They are very waterproof and provide excellent protection against ground moisture.
What if I’m dealing with a leak and not condensation?
This is a very important distinction to be made. Rainfall will increase air humidity and this will cause condensation so having more moisture coming through your tent after it rains can be explained by that fact. Still, if the rain was too heavy for the construction of the tent or if the tent has a tear in the fabric you might have a leak. Condensation is inevitable and manageable, a leak can become a nightmare.
As a rule of them before you go camping, you should set up your tent with its rainfly and spray it down heavily with a hose. This is called weathering and it should be done extensively with any new tent you buy. This should highlight any tears or leaky spots but it is also a necessity with tents made of certain materials.
Canvas and polycotton tents, when brand new, can be fairly coarse and water can leak through them easily. They need to be watered down first to help the weaves tighten up and make it more waterproof. This also applies to the stitching of some tents which often requires moisture to help it expand and harden.
You might also encounter what looks like a leak but really isn’t. When condensation occurs on the flysheet and soaks into the tent anything that touches it will become moist. Some things will absorb this condensation like a sponge (think toilet paper) and it will look like a small leak has sprung in your tent.
If you do have a real leak on your hands then you will need to check over the entire tent. Start with the seams as these are often the source of a leak. A fix here can be as simple as applying some seam sealant which can be gotten at most camping outlets. If the leak is coming from a tear in the tent itself then you will have to patch it and then apply a seam sealant.
Condensation is an inevitability when your camping but it is possible to reduce how severe it is. With the right tent, in the right place with the right camping habits, you will barely have to think about moisture in your tent. As with all things in camping, there are elements out of your control but there are also steps you can take to prepare yourself. Preparation and knowledge will readily arm you against any issues you might have with condensation.
Bonus tip: Controlling condensation in your tent during winter adds an extra layer to the challenge and you can see how one camper manages in the video below!