Where Humidity Comes From: This Is What Causes Humidity

Humidity is a measure of the amount of water vapor in the air. It can be caused by many different things, including temperature, weather conditions, and even your daily activities. In this article, we’ll explore the different types of humidity, how it affects your daily life, and the causes of humidity.

We’ll also provide tips for reducing the amount of humidity in your home or office, and discuss the risks and benefits of humidity. Finally, we’ll answer some common questions about humidity to satisfy further curiosities.

Where Humidity Comes From

Let’s take a deep dive into where humidity comes from and its causes.

Where Humidity Comes From & Causes

You might want to know where humidity comes from and its causes because it can affect your life in different ways. For example, humidity can make you feel hot and sweaty or make it harder for you to breathe. It can also cause things to grow or get rusty.

You might want to learn more about humidity so you can reduce or increase it in your home or office depending on the climate or the environment indoors.


Humidity is a measure of the amount of water vapor in the air. Water vapor is invisible, but it affects both temperature and humidity. The more water vapor there is in the air, the higher the humidity will be.

Warmer air can hold more water vapor than cooler air, so humidity usually increases as the temperature rises.

When the air becomes saturated with water vapor (100% humidity), condensation will occur. This is why we see dew on plants and grass early in the morning – the temperature has cooled overnight, causing the air to reach 100% humidity and resulting in condensation.

Conversely, when the temperature decreases, the air will reach a point where it can no longer hold all the water vapor – this is known as “dry air.”

Dry air feels cool and can cause static electricity because there are fewer water molecules to conduct electricity.

Weather Conditions

According to the National Weather Service, there are a variety of weather conditions that can cause humidity. Warm, moist air is the most common cause of high humidity levels. When this air collides with cold air, it can create condensation, which can lead to fog or dew.

Another cause of high humidity is evaporation, which occurs when water evaporates from the surface of the earth.

This process releases water vapor into the air, which can then rise and form clouds. Precipitation, such as rain or snow, can also increase humidity levels by adding water vapor to the air.

Plants and trees release water vapor through a process called transpiration. This water vapor then rises into the atmosphere and can contribute to high humidity levels.

All of these factors can contribute to higher-than-normal humidity levels.

Daily Activities

There are a number of daily activities that can cause humidity in a home, from cooking and showering to doing laundry and running humidifiers. In fact, anything that adds moisture to the air can contribute to higher indoor humidity levels.

While a certain amount of humidity is necessary to keep your home comfortable, too much humidity can create problems like mold and mildew growth.

That’s why it’s important to monitor the indoor humidity levels in your home and take steps to keep them in the comfortable range.

Some simple tips include opening windows when showering or cooking, using exhaust fans to remove moisture-laden air, and keeping your home clean and dust-free.

By taking these measures, you can help prevent indoor humidity levels from getting too high.

Recommended Humidity Level in a Home

The ideal humidity level in a home should be between 30 and 50 percent, according to the Environmental Protection Agency. Maintaining the proper humidity level in your home helps prevent the growth of mold and dust mites, two common triggers of allergies and asthma.

It also helps to protect wood floors and furniture from warping and cracking. If the air in your home is too dry, you may notice static electricity, dry skin, and nosebleeds.

On the other hand, if the air is too humid, you may experience musty odors, condensation on windows, and peeling wallpaper.

To maintain a comfortable humidity level in your home, use a humidifier or dehumidifier as needed.

Check the relative humidity levels regularly with a hygrometer to ensure that your home remains at a comfortable level.

Controlling Humidity

Control of relative humidity is essential for many reasons. Higher humidity retards evaporation which is necessary for drying laundry and paint. In offices and libraries, static electricity discharge from computers and other electronic equipment can be controlled by keeping relative humidity low.

Programs that control heating, ventilation, and air conditioning (HVAC) take into account both temperature and relative humidity when determining set points to maintain comfort conditions indoors while conserving energy.

In general, people feel more comfortable when relative humidity is between 30% and 50%. People can have difficulty breathing when relative humidity goes above 60%.

Bacteria and mold grow best at relative humidities between 60% and 80%. To control relative humidity, either the amount of water vapor in the air must be increased or decreased or the temperature must be changed.

To increase the amount of water vapor in the air, humidifiers are used. To decrease the amount of water vapor in the air, dehumidifiers are used.

By using a hygrometer we can measure either absolute or relative humidity in indoor or outdoor environments which allows us to then do something about increasing or decreasing the level as needed.

There a many factors to consider when controlling humidity but by monitoring it with a hygrometer, we can achieve an ideal balance for our specific needs.

How to Lower Humidity in Your Home

Humidity levels in a home that are too high can lead to a variety of problems, including the following:

  • Condensation on windows
  • Musty odors
  • The growth of mold and mildew
  • Allergy-like symptoms from mold and mildew

If you’re struggling with high humidity, there are a number of things you can do to bring the level down.

Use a Dehumidifier

One option is to use a dehumidifier. Dehumidifiers work by drawing in moist air and then releasing it back into the room after the water has been extracted.

More Effective Ventilation

Another way to reduce humidity is to ventilate your home more effectively. This can be done by opening windows and doors on opposite sides of the house to create a cross breeze, or by using an exhaust fan in the kitchen and bathroom.

Ensure Your Dryer Vents to the Outside

A dryer should be vented to the outside of the home. Otherwise, you’ll have an accumulation of condensation on your windows and walls where mold and mildew will surely thrive.

Find and Fix Water Leaks

Water leaks can often go undetected for long periods of time, which can create the perfect environment for mold to grow. Mold thrives in humid environments, and even a small leak can increase humidity levels enough to encourage mold growth.

In addition to causing property damage, mold can also pose serious health risks. exposure to mold can cause respiratory problems, skin irritation, and allergic reactions.

For these reasons, it is important to take action as soon as a water leak is discovered. The first step is to locate the source of the leak and then repair it.

Once the leak has been fixed, it is important to dry the area completely and reduce humidity levels to prevent mold from returning.

Use Your Exhaust Fans

Exhaust fans used in both bathrooms and kitchens are an essential tool for preventing moisture and mold build-up in your home. Removing excess humidity from the air helps to keep indoor spaces comfortable and reduces the risk of condensation and mold growth.

Exhaust fans can also help to reduce allergy symptoms and improve air quality. When used properly, exhaust fans can be a powerful weapon in the fight against indoor moisture and mold.

However, it is important to choose the right size fan for your space and to ensure that it is properly vented to the outdoors.

Otherwise, you may find that your exhaust fan does more harm than good.

With some effort, you can lower the humidity in your home and create a more comfortable living environment.

How to Increase Humidity in Your Home

There are a few things you can do to increase the humidity in your home. One way is to invest in a humidifier. Humidifiers release water vapor into the air, which can help to raise the overall humidity level. Another option is to boil water on the stovetop.

As the water boils, it will release steam into the air, which can also help to raise the humidity level. You can also place bowls of water around your home.

The evaporation of the water will add moisture to the air.

Humidity FAQs

Still curious about humidity? Maybe the questions and answers below will help feed your craving.

What is the difference between relative humidity and absolute humidity?

There is a distinct difference between relative humidity and absolute humidity as explained below:

Relative Humidity

Relative humidity is a measure of how much water vapor is present in the air relative to how much water vapor the air can hold at a given temperature. The warmer the air, the more water it can hold.

Absolute Humidity

Absolute humidity is the actual amount of water vapor present in the air. It is usually expressed in grams of water vapor per cubic meter of air.

Key Differences

The difference between relative and absolute humidity is that relative humidity varies with temperature, while absolute humidity does not. For example, if the temperature decreases, the amount of water vapor that can be held in the air also decreases.

However, the actual amount of water vapor present in the air remains constant.

As a result, the relative humidity will increase even though the absolute humidity remains unchanged.

This relationship between relative humidity and temperature is what allows us to use relative humidity as a measure of moisture content in the atmosphere.

What is dew point?

The dew point is the temperature at which water vapor in the air will condense into liquid water. Dew point is often confused with relative humidity, but they are two distinct measures.

Relative humidity is a measure of how much water vapor is present in the air relative to the maximum amount that could be present at that temperature.

The dew point is the temperature at which the air would reach 100% relative humidity. When the dew point and the temperature are the same, the air is saturated with water vapor and condensation will occur.

The dew point is a crucial element in weather forecasting, as it can help to predict precipitation, fog, and dew.

It can also be used to assess the comfort level of indoor air. The higher the dew point, the more likely it is that condensation will occur and the air will feel muggy.

For most people, a comfortable range for the indoor dew point is between 30 and 50 degrees Fahrenheit.

How can I tell if the humidity in my home or office is too high?

A hygrometer is a tool that is used to measure humidity levels. There are two types of hygrometers: analog and digital. Analog hygrometers use a mercury or alcohol-filled bulb that expands or contracts as the level of humidity in the air changes.

This expansion or contraction moves a needle on a dial, which indicates the current humidity level.

Digital hygrometers, on the other hand, use an electronic sensor to measure humidity levels. They then display this information on an easy-to-read LCD screen.

To use either type of hygrometer, simply place it in the room that you want to measure. After a few minutes, you will be able to see the current humidity level.

Hygrometers may be purchased from your local home improvement store.

What are the risks and benefits of humidity?

Humidity, or the amount of water vapor in the air, is a key part of the environment. It affects everything from how we feel to how well plants grow. While humidity is necessary for many aspects of life, it can also present risks alongside the many benefits.

Risks of Humidity

While a certain amount of humidity is necessary for comfortable living, too much humidity can lead to a number of health and safety risks.

  • Excess humidity can cause mold and mildew to grow, leading to respiratory problems and other health issues.
  • High moisture levels can also damage wood furniture and lead to the growth of pests such as cockroaches and moths.
  • In extreme cases, high humidity can lead to structural damage as wooden beams swell and warp.

It’s important to monitor humidity levels in your home and take steps to reduce moisture if necessary. Using a dehumidifier or opening windows on dry days can help to keep humidity levels in check.

By taking these precautions, you can avoid the risks associated with excessive moisture in the air.

Benefits of Humidity

High humidity has its drawback, yet it also has many benefits.

  • Humidity can help to ease respiratory problems by thinning mucus and making it easier to breathe.
  • The moisture in the air from the humidity helps keeps skin from drying and becoming flaky and itchy.
  • Wood furniture and wood floors can benefit from added moisture in the air. If they lose too much moisture, they begin to shrink and crack.

The key to enjoying the benefits of humidity is to maintain a healthy balance. Too much or too little humidity can be detrimental to health, so it is important to find a comfortable middle ground.

Why is humidity important?

Met Office explains that water vapor is one of the key greenhouse gases. The atmosphere contains more water vapor than any other greenhouse gas.

We couldn’t survive on Earth without water vapor. Water vapor, a greenhouse gas, allows solar energy to pass through and warm the Earth.

The Earth then radiates energy away, however, some of this energy is captured by greenhouse gases that trap heat on the way out.

The Earth’s surface temperature is 58.1 °F on average, but without greenhouse gases, it would be closer to -0.4 °F.

For the transfer of energy around the Earth, water vapor is crucial. Water is converted into water vapor by the Sun’s energy, which can then be easily transferred through the atmosphere.

When the water vapor eventually turns back into the water, heat is released. The development of storms depends in large part on this heat.

Humidity plays an important role in atmospheric pressure, which affects the weather and climate. By regulating the amount of water vapor in the air, humidity helps to stabilize the atmosphere and prevent extreme weather conditions.

Thus making it an important factor in both our everyday lives and the global climate.


Knowing where humidity comes from and the causes of humidity are important so that you know how better to control it when humidity levels are less than pleasing. Maintaining a relative humidity level of between 30 and 50 percent will ensure the moisture in the air is neither too low nor too high.


Trina Greenfield, Author
SmackDown Media LLC

About the Author:
Trina Greenfield, the owner of SmackDown Media LLC, is passionate about providing information to those interested in the air quality in and around their homes. Trina writes content about things she’s passionate about, such as safe, in-home air, educational platforms for children and adults, as well as all things family-related.