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why my room is so humid

Why Is My Room So Humid? 7 Reasons Explained

When winter is over and the temperature starts to rise, our task shifts from combating dryness to fighting dampness. Many people want to know why their rooms are so humid before taking action. After all, understanding the causes can aid in solving the problem. 

The causes of high humidity in the house often come down to the high outdoor humidity, the leaks, and the problems with your AC. 

I will walk you through each cause, show you the risks of high humidity in the room, and how to deal with it in this post. 

Without further ado, let’s get started!

What is considered high humidity?

Humidity, also known as relative humidity, is a common indicator that describes the percentage of water vapor in the air compared to the amount of water that the air can hold at a given temperature.

According to various sources, it is considered high when the indoor humidity level exceeds 50% or 60%.

The high humidity level can result in many bad consequences. For example, when the humidity level is 70%, molds and fungi will certainly grow. (We’ll get to that later.)

Therefore, you should investigate the causes of the high humidity in your home and find a way to deal with it as soon as possible.

Reasons why my room is so humid

what causes high humidity in a house

Several factors can contribute to the high humidity in the house. You can exclude them one by one and find the cause in your room.

High outdoor humidity

Believe it or not, even if you keep your HVAC system running, the outdoor humidity still affects the indoor humidity. 

Moisture and air will constantly enter and exit your home through windows, doors, and other crevices.

When the temperature goes up in spring and summer, more water will evaporate into the air from the ground, and the air is capable of holding more water. As a result, the outdoor air will be very humid, which will increase your house’s indoor humidity level.

Aside from that, if you live near a lake or forest, the humid environment outside will play a constant role in your life. After it rains, the outdoor climate will be extremely humid.

Daily activities

Who can say no to a delicious dinner? But cooking is an activity that will consume a lot of water. A portion of the water will evaporate into the air, increasing the humidity in your kitchen. The moisture will gradually spread to other rooms.

Showering is another daily activity that will add moisture to your room. As I said, the higher the temperature, the more water the air can hold. When you enjoy a hot shower, you leave more moisture in the air in your bathroom. It is also the leading cause of mold growth in bathrooms.

Beyond that, hanging clothes in the room, mopping the floor, running the washing machine, and mopping the floor are all activities that can make your room humid. Even our breathing and sweating can contribute to moisture.

Poor ventilation

From what I mentioned above, our daily activities will raise our indoor humidity level. If the house is poorly ventilated, the moisture will accumulate continuously. With time, our house will get too humid to stay in.

Rising damp 

Rising dampness often occurs in older buildings due to the lack of damp-proof course.

Capillary action allows groundwater to enter the house through the bricks and masonry.

Rising dampness can be detected by the presence of condensation on the wall or flaky plaster.


Leaks can happen in many places in your house, like bathrooms and basements. Cracks in the pipes are possible, and the valve can rust over time. If leaks are not treated promptly, they can become serious. Water seeping through the small crevices can wreak havoc in the long run.


Sometimes, the cause of high humidity in your room is the location. The basement is usually more humid than other rooms due to the low temperature and the moisture seeping through structural cracks.

AC issues

Many users have reported that even when the air conditioner is turned on, the room remains humid.

Many reasons can contribute to it, such as the AC being oversized and not having enough time to suck up the humidity before reaching the targeted temperature. Or it is just because your unit requires repair.

Check out our post that explains “why is my house so humid with the air conditioner on” here.

Risks of high humidity in the house

Excess moisture in your room will not only make you feel uncomfortable, but it will also pose numerous risks to you and your property.


Our bodies will continue to sweat in order to cool down. When the humidity rises, our sweat cannot evaporate quickly enough to reduce our body temperature, so we sweat more to compensate. Dehydration occurs when too much water is sweated.

Respiratory issues 

Again, the excessive humidity will promote the growth of mold and dust mites. These microorganisms will cause lung infections, allergic reactions, or even asthma flare-ups when we breathe in. 

Sleep disorder 

Add to that the respiratory ailments, dampness can make us feel overheated and hard to breathe, causing sleep disruptions that everyone hates.

Damage the structure of your house

Not only you but your house will be affected by humid air. The structure and furniture will absorb moisture which will cause swelling, warping, rotting, and rusting. If the structure is severely damaged, you will be in danger.

How to deal with high humidity in the house?

As you will be exposed to many risks, you can’t leave the humid environment untreated. Luckily, there are many ways to remedy it.

Use a dehumidifier 

A dehumidifier is a specific device to remove the moisture in the air. It is affordable without using a lot of electricity.

Plug it in and run it for a few hours a day once the humidity inside reaches a certain level.

Run an AC

air conditioning

AC, like a dehumidifier, can help to reduce humidity. It can remove moisture while also adjusting the room temperature.

Move some plants in and some out

Some plants can increase the humidity, whereas some can absorb more moisture. For instance, spider plants are great species for increasing indoor humidity and peace Lily is good at absorbing humidity. 

So you should check the characteristics of your houseplants and decide which should be left in the house and which shouldn’t.

Increase ventilation

Installing and running exhaust fans in the bathroom and kitchen is necessary for removing dampness. Besides, opening your windows regularly is another simple but effective way to solve the problem.

Wrapping up

If you have ever wondered why your room is so humid, I believe this post has provided a satisfactory answer.

There are many causes of high humidity indoors, and sometimes you need to make an array of modifications in a bit to solve the issue. 

Climate outdoors plays an important role in indoor humidity. Your activities and leakages also could be the culprits. Sometimes, the rising dampness can be the cause. 

I have summarized seven reasons for this problem in the post. You can write them down and check which one could be the devil in your home. 

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested more than 150 products in person, including humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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