Feeling uncomfortably sticky and clammy at home lately? Chances are it’s a result of the high humidity levels! High humidity can be an issue any time of year, but is particularly difficult to tolerate during hot summer months. So what causes high humidity in a house?

We’re glad you asked!

Previously, we talked about the symptoms of high humidity at home. Now, let’s discuss the things that commonly cause it, alongside tips that will help you reduce it. So don’t let excess moisture ruin your mood – learn what causes high humidity ina house so you can stay cool and comfy at home!

Lack of Ventilation

Poor ventilation in a home can cause humidity to build up, especially in bathrooms and kitchens where there is a lot of excess moisture. This can be troublesome during warmer days, as the humid air trapped inside can lead to condensation on walls and windows. Aside from increasing humidity in your home, it can also create a breeding ground for mold and mildew.

To fix this, you need to ensure proper ventilation in your house. Start by opening your windows and doors to increase air flow. You can also use exhaust fans in bathrooms and kitchens, as well as make sure that your attic and crawl spaces are properly ventilated.

Installing vents and fans, as well as a good air conditioner, can help to decrease humidity in your home, improve air circulation, and minimize indoor air pollutants as well. And make sure to employ proper insulation techniques to prevent moisture buildup.


If you’re wondering what causes high humidity in a house, it’s leaks. Leaks in your home, especially in your roof and plumbing, can leave you with to high humidity levels. Even worse, as water seeps into your home, it can create the ideal environment for mold, mildew and other microorganisms to grow. This can lead to musty odors, not to mention health problems for you and your family.

To fix leaks, you should first locate them and have them repaired as soon as possible. If the leak is in the roof, you should call a professional roofer to fix it. In case the leak is in your pipes, you should call a plumber. Alternatively, you can channel your inner repairman and do these things yourself.

It’s also important to properly maintain appliances, such as your dishwasher, washing machine, and air conditioner, to prevent leaks. If the damage is severe and there’s already mold growth, it’s important to call a professional mold remediation company so they can determine what causes high humidity in a house.


Houseplants release moisture into the air through a process called transpiration. This can lead to high humidity levels in a home, especially if you have too many plants or they are too large.

So while houseplants can provide many benefits (such as improving poor indoor air quality), it’s important to keep track of how much moisture they’re releasing. Try reducing the number you keep inside your home, either by moving them to a different location with better ventilation or by taking them outside.

Another option is to group plants together in a room with a window. This allow the excess moisture they release to easily escape outside. You can also consider using a dehumidifier in the room with plants to help lover excessive humidity levels.

Additionally, you should regularly check the soil of your plants as well. If it’s too wet, it’s better to let them dry out before watering them again.

Cooking and Showering

Cooking and showering can also result in excessive moisture in the air, which can lead to high humidity in your home. The steam from cooking and showering can cause visible condensation and wet stains on walls, windows and floors. Again, aside leaving too much moisture, this can potentially case mold and mildew growth.

To fix this, you can install exhaust fans in your kitchen and bathroom. This will help remove moisture from the air and lower your home’s humidity level. You can also open windows or use an air purifier to improve air flow and control humidity in your house.

Another option is to take shorter hot showers, or opt for cooler showers. That way, you can reduce the amount of water vapor produced. When cooking, make sure to use a lid on pots and pans. This helps trap steam and reduce the amount of moisture released into the fresh air. In addition, if you have a vent hood in your kitchen, make sure it’s working properly, and use it when cooking.


Climate can also play a role in the amount of excess humidity you have to deal with at home. If you live in an area with high temperatures and high rainfall, you’ll constantly face elevated humidity levels. This can make it more difficult to control humidity in your home. So if you’re wondering what causes high humidity in a house, check where you’re located.

Luckily, there’s a way for you to combat high humidity (and no, you don’t have to move to a new state that doesn’t come with humid environments). Simply install a dehumidifier in your home, and it will remove excess moisture from your home’s air.

You can also rely on a good air conditioning system, which can help to reduce humidity, control moisture, and regulate the temperature inside your home. What’s more, make sure to properly seal your house and use insulation to prevent too much moisture from entering your home from outside.

Another great option is to use window treatments like shades or blinds that can block sunlight and reduce heat gain in your home. Finally, if you live in an area with humid climates, it’s important to be vigilant about maintaining good ventilation and keeping your home dry.

Improperly Used or Maintained Humidifiers

If you want to know what causes high humidity in a house, using a humidifier improperly is one of them. If the humidifier in question is not cleaned regularly or if it’s over-moistening the space, it can increase humidity levels even further. Again, this can also potentially create the perfect environment for mold, mildew, and other microorganisms to grow, not to mention cause damage to the wood and other materials in your home.

To remedy this, you should make sure to follow the manufacturer’s instructions for cleaning and maintaining of your humidifier. It’s also important to monitor the humidity levels in your home with a hygrometer and adjust the settings accordingly.

The ideal humidity level for a home is between 30% and 50%. If you notice that the humidity level is too high, you should turn off or reduce the output of your humidifier until the humidity returns to a comfortable level. Lastly, make sure to use a humidifier with a built-in thermostat that can automatically reduce high humidity levels.

Oversized Air Conditioners

An oversized air conditioner can lead to high humidity levels in a home because it cools the air too quickly, leaving little time for the system to remove the excess moisture from the air. This can cause condensation on walls, windows and floors, and again lead to mold and mildew outbreaks.

An oversized air conditioning system will not only produce excessive humidity, but also consume more energy. This will leave your air conditioning unit not running as efficiently as it should, as well as give you a headache when when the energy bill shows up.

To fix this, you can have a professional HVAC technician properly size your AC unit to match the size of your home. They will take into account factors such as the square footage of your home, the number of windows, the number of people living in the home, and the local climate.

Additionally, make sure to keep your unit’s air filter clean. This will help improve the efficiency of your air conditioner and also help to remove moisture from the air.

Improperly Sealed or Insulated Crawl Spaces or Basement

Failure to seal or insulate basements or crawl spaces can lead to high humidity in your house. This is because these areas are often damp, dark, and poorly ventilated. Plus, humid outdoor air can easily seep into these areas and penetrate onto your main living space.

To fix this, you can seal and insulate your basement or crawl space to ensure less moisture enters your home. This can be done by caulking and weatherstripping any cracks or gaps in the walls, floors, and windows, as well as by installing a vapor barrier on the walls and floors.

Again, you can also use a dehumidifier in the basement or crawl space to absorb moisture inside these areas. Additionally, make sure to properly ventilate the area by installing vents in the walls or by using a ventilation fan or an AC unit.

Dampness, Moisture and Water Damage From Natural Disasters

Dampness, moisture and water damage from natural disasters such as floods, storms, hurricanes and heavy rains can lead to high humidity in your home. These events can cause water to seep into the walls, floors, and ceilings. If not addressed promptly and properly, it can cause serious health issues and cause damage to building materials.

To resolve this problem, you need to take immediate action to dry out the affected areas. Use a wet-dry vacuum to remove standing water, fans and dehumidifiers to dry out any wet materials, and a couple of other tools to remove damaged ones.

After the immediate cleanup, have a professional inspect your home for any structural damage, mold growth or pest outbreaks. They will also be able to assess the extent of the damage and recommend the best course of action.

Additionally, it’s important to have a plan in place in case of future natural disasters. Invest in things like as sandbags to protect your home from flooding, or a generator to keep your sump pump running during power outages.

Outdoor Humidity

Finally, humidity from outdoor sources live swamps, rivers, and what-not can easily find its way into your home, leading to high indoor humidity levels. This can be further exacerbated by a number of factors, such as heavy rainfall, high temperatures, and a lack of ventilation.

To avoid these issues, you can start by identifying the sources of outdoor humidity and taking steps to reduce or eliminate the humidity they bring. For example, you can make sure that your gutters and downspouts are in good working condition to prevent water from seeping into your home.

Again, you can install a dehumidifier or HVAC system to help remove the extra moisture from the air. Proper ventilation is also crucial for keeping preventing outside humidity at bay. So make sure that your home has adequate air exchange to help dissipate moisture.

Minimize Humidity in Your House

Do you find your house so wet and humid that it’s making you feel all icky and uncomfortable? Learn what causes high humidity in a house in order to get your life back. By watching out for the signs listed above, you’ll be able to make sure the air inside your home isn’t so moist and sticky. If symptoms persist, best call your trusted AC repair company.



Why is humidity so high in my house?

Humidity levels in a house can be high due to various factors such as poor ventilation, damp weather, cooking, showering, and house plants. High humidity can lead to mold growth, musty odors, and decreased air quality. To reduce humidity, consider using a dehumidifier, improving ventilation, fixing leaks, and limiting activities that add moisture to the air.

Is 70% humidity too high for house?

A relative humidity level of 70% is generally considered to be too high in a house, as it can promote mold growth and affect indoor air quality. Optimal indoor humidity levels are usually between 30-50% for comfort and to prevent mold and other moisture-related issues. Maintaining low humidity levels through the use of a dehumidifier, air conditioning, and proper ventilation can help to keep your home healthy and comfortable.

What are signs of high humidity in home?

High humidity in a home can cause dampness, musty odors, and condensation on windows, walls and surfaces. Excessive humidity can also lead to mold growth and peeling paint. High humidity can be measured using a hygrometer, with indoor levels between 30-50% considered comfortable.

Does aircon reduce humidity?

Yes, air conditioning can reduce humidity by removing moisture from the air and cooling the room. The AC unit works by evaporating the moisture, which is then expelled from the room through a drain pipe. It’s important to regularly maintain the air conditioning unit to ensure it’s functioning properly and effectively reducing humidity levels.
what causes high humidity in a house