A humidifier can be a valuable addition to your home, especially when the air is dry or if you live in a place with relatively low humidity levels. However, if not used properly a humidifier might not be the best investment for your home.
Yes, humidifiers can cause mold in a room and on walls. Humidifiers are likely to cause mold on walls when they are not used correctly and end up increasing the humidity levels in the home, beyond the recommended relative humidity levels for indoor air.
The formation of mold in any room or surface is based on the presence of four key factors, high moisture levels, conducive temperatures (above 40 degrees Fahrenheit), oxygen, and organic substances or food.
If your home has very high moisture levels and the other conditions supporting mold growth are met, it will not matter whether or not you are using a humidifier because these conditions will promote the growth of mold.
Very high levels of humidity in your home can cause mold and make the air in your home dewy and unhealthy.
Understanding the correct levels of humidity that you should maintain to prevent the growth of mold is important in reducing the risks of respiratory health issues associated with too high or too low levels of humidity in your home.
This post addresses the following concerns:
- Can a humidifier cause mold in a room?
- Can humidifier cause mold on walls?
- Common sources of mold in homes
- How to prevent mold in a room when using a humidifier
- FAQs about humidifiers and mold
Can a Humidifier Cause Mold in a Room
Humidifiers like other sources of moisture in your home can promote the growth of mold. By themselves, humidifiers have a low likelihood of causing mold in your home.
If there are other causes of mold in your home, such as leaking water pipes, the use of a humidifier can contribute to the high moisture levels in your home and lead to mold growth.
Regardless of other underlying causes of mold in your home, there are instances where humidifiers by themselves can cause mold growth.
Instances where humidifiers can cause mold in a room:
Humidifier to Room Size Ratio
It is important to consider the size or capacity of your humidifier before using it in any room. Most portable humidifiers can be used in any room as the moisture released from the humidifier is relatively low. However, some humidifiers are meant for larger rooms or whole houses.
If you are using a large humidifier in a small space, the amount of moisture released into the room or the space could contribute to mold growth, especially if the humidity levels in the room or space exceed the recommended relative humidity for indoor spaces.
For instance, if you are using a whole-house humidifier in your home it is important to ensure that the humidistat on the humidifier is set at 30 to 50% relative humidity to ensure that the moisture released by the humidifier does not oversaturate the air.
Duration of Humidifier Usage
You should also be mindful of the number of hours that your humidifier runs per day. Ideally, you should use your humidifier based on your needs.
If the air in your home is excessively dry, like in the case during winter, you can use your humidifier for longer hours, when compared to summer or warmer seasons.
Running your humidifier continuously throughout the day can increase the humidity levels in your home, especially if you live in a relatively humid area or if the air in your home is already damp.
Dirt
A humidifier that is not cleaned regularly creates the perfect environment for the growth of mold. Mold does not necessarily require soil to grow. It is a fairly opportunistic plant and will grow anywhere as long as there is moisture, organic material, oxygen, and the right temperatures.
If you do not clean your humidifier regularly, the stagnant water in your humidifier will be the perfect environment for mold growth.
A film of dirt, dead insects, and other micro-organisms can form in water that has been left standing for several days. The film of organic microbes will act as food for mold and promote the growth of mold in your humidifier.
Continued use of a humidifier that has not been cleaned for a long time will mean that the microbes like mold and bacteria will be released into the air around your home.
Some of the mold released from the humidifier can end up in the air around your home, your wall, and other surfaces.
It is important to clean your humidifier regularly to prevent microbial growth. Ensure that you clean your humidifier at least twice a week if you use it regularly. You should also ensure that you empty the water in your humidifier when you are not using it.
Can Humidifier Cause Mold on Walls
While it is highly unlikely, it is important to note that humidifiers can cause mold on your walls.
Placement
Humidifiers will only cause mold on your walls if you place a humidifier very close to your wall when you are using the humidifier.
For instance, if you constantly place a humidifier on a bedside table near a wall, you might increase the likelihood of mold growth on that section of your wall.
The risk of mold growth will also be determined by factors such as the duration of humidifier usage and the amount of moisture released by the humidifier.
If the humidifier released high levels of moisture and is constantly placed near a specific wall, then the humidifier can cause mold growth on the wall.
You should place your humidifier at a central location in your room to ensure that it is not close to any wall. This trick can save your walls from mold-related damage.
The Direction of Humidifier Nozzle
Most humidifiers have a nozzle that can be used to direct the release of humidity in the room. If you place a humidifier near a wall and direct the nozzle towards the wall, then you will be increasing the risks of mold growth on the wall.
Note that directing the nozzle of the humidifier towards a wall once might not contribute to mold growth but continued exposure of the wall to the moisture released by the humidifier over time will increase the risks of mold growth.
In general, whether or not a humidifier will lead to the formation of mold in your home will depend on many underlying factors such as pre-existing levels of humidity in the home and factors associated with the placement of the humidifier.
If the humidity levels in your home were already high, then you risk damaging your walls by using a humidifier.
Common Sources of Mold in Homes
| Common Sources of Mold in Homes |
| Leaking water pipes |
| Living in humid areas like Florida |
| Leaking roof |
| Damp or wet clothing |
| Condensation |
Humidifiers are not the only potential cause of mold in a room. If you are concerned about the risk of mold in your home, you should ensure that you assess and fix any other potential causes of mold in your home. Here is a list of common causes of mold in indoor spaces that you can use.
Leaking water pipes
Water pipes can leak and contribute to the growth of mold around your home. Leaking pipes are considered one of the main causes of mold growth in homes.
Water leakage can cause the growth of mold on walls, ceilings, and wooden flooring. If you notice mold in these areas, it is advisable to check if there are any damaged water pipes. Ensure that you replace or repair the water pipes to avoid further growth of mold.
Living in humid areas
If you live in a humid area, you are likely to notice mold around your home. The growth of mold can worsen when you live in a humid area and opt to use a humidifier in your home.
Having a humidistat is a great solution for ensuring that you keep track of the changing humidity levels in your home, especially if you live in a humid area.
Leaking roofs
Leaking roofs can contribute to water damage and the growth of mold, especially during the rainy seasons. Harsh weather conditions can contribute to progressive wear and tear of your roof.
If your roof is damaged, moisture can leak into your attic or ceiling slowly over time and eventually promote the growth of mold.
Condensation
While the winter season is associated with dry air, which might necessitate the use of a humidifier, condensation build-up is also common during the winter season.
A build-up of condensation may be noticeable on concrete floors, tiles, window fixtures, or other places in your home. If there is condensation build-up around your home during the winter season, ensure that you check your ventilation and the spaces near your door and windows for damage.
Damp or Wet Clothing
If you dry your clothes indoors, you should ensure that your laundry room is well-ventilated. The dampness associated with wet clothes can increase the level of humidity in the air and create a conducive environment for the growth of mold and other microbes.
How to Prevent Mold in a Room When Using a Humidifier
Placement: Place your humidifier at a central location to ensure that the moisture released from the humidifier is equally distributed in the room. This will prevent the accumulation of moisture in one area of the room and will decrease the risk of mold growth.
Duration of usage: Only use your humidifier when you need it, especially if you live in a humid area. Do not use your humidifier for 24 hours unless the air in your home is dry or the humidity levels in your home are below the recommended levels.
Clean the humidifier: Ensure that you clean the humidifier regularly. A dirty humidifier will only promote the growth of unwanted microbes. Most humidifiers have instructions on the proper way to clean them. Simply follow the manufacturer’s instructions to clean your humidifier.
You can clean the humidifier with a mixture of water and hydrogen peroxide. The hydrogen peroxide will be effective in destroying any microbes in the humidifier.
After washing your humidifier with soap and warm water or based on the manufacturer’s recommendations, you can mix half a cup of water with two to three tablespoons of hydrogen peroxide in the humidifier and let it stand for about 10 minutes before emptying it.
Eliminate dampness: If you notice any water spills on surfaces around your home or where you have placed the humidifier, it is important to dry the water spills to avoid mold growth. You should also repair any broken fixtures around your home that might contribute to the flow of humid air in your home.
Hygrometer: You can invest in a hygrometer to check the humidity levels in your home. A hygrometer will help you determine whether the humidity levels in your home are above or below the recommended levels. Ensure that the humidity levels in your home do not go beyond 55% to prevent mold growth.
In Summary
Unless you are using the humidifier for prolonged periods in a room that already has high humidity levels or you are using a humidifier meant for large rooms in a small space, humidifiers have a low likelihood of causing mold in your home.
Note that, you should also clean your humidifier regularly and change the water in the humidifier to avoid mold growth. Proper usage of your humidifier will eliminate the risks of mold growth.
Humidifiers are also great for protecting the electronics in your home from damage associated with prolonged exposure to dry air. Check out the article below to read more about how humidifiers can protect your electronics from dry-air damage.
Recommended read: Are humidifiers safe around electronics
FAQs About Humidifiers and Mold
Do humidifiers make your room moldy?
Humidifiers do not make a room moldy as they only increase the level of humidity in a room. If you are using a humidifier in a room that already has high humidity levels, then you might notice that the room is already moldy regardless of whether you use a humidifier.
If your room is moldy, ensure that you ventilate the room properly and fix any damaged water pipes, roofs, windows, doors, or ventilators around the room. Additionally, you should engage a professional in getting rid of the mold.
How do you prevent mold on walls when using a humidifier?
If you are using a humidifier, you can prevent mold on walls by ensuring that you placed your humidifier at a central location in the room and avoid using your humidifier for prolonged periods.
You should also assess other causes of high humidity in your home and ensure that you retain the humidity levels in your home at the recommended levels.
Is it OK to sleep with a humidifier every night?
It is okay to sleep with a humidifier every night if you live in an area with low humidity levels or if the relative humidity level in your home is below the recommended ranges.
Humidifiers can increase the moisture in the air around your home and make it easy to breathe. Just ensure that you check the relative humidity levels in your home first if you plan to use your humidifier continuously.
Can humidifiers cause breathing problems?
Humidifiers do not cause breathing problems as they are designed to resolve common breathing problems associated with dry air.
The only case that a humidifier can cause breathing problems is if the humidifier has not been cleaned properly or dirty water is used in the humidifier as these cases would suggest that any unpleasant micro-organisms in the water are released into the surrounding air.
Can a humidifier cause mold in carpet?
Depending on usage a humidifier can cause mold on carpet. If you place your humidifier on your carpet regularly when using it, the moisture released by the humidifier can accumulate on the carpet and promote the growth of mold.
Similarly, if you pour water on your carpet and fail to dry the carpet, you might notice some mold growth on the carpet. When using your humidifier, it is advisable to place it on a raised surface such as a table to avoid water spills or accumulation of moisture on surfaces that might not dry easily.
Humidifier mold symptoms
Your humidifier can also be a conducive place for mold to grow, especially if you do not clean your humidifier regularly or you fail to empty the water in your humidifier when you are not using it.
Some of the symptoms that you might experience if there is mold in your humidifier include stuffy nose or flu whenever or after using your humidifier, wheezing or cough, skin rashes, chest tightness, breathing difficulties, headache, dizziness, eye dryness, and itchiness.
If you have a history of asthma or any other respiratory health issue, you might notice an exacerbation of your symptoms.
While these symptoms are commonly linked to exposure to mold, it is important to note that these symptoms can also be associated with other microorganisms.
In case you experience these symptoms, clean your humidifier regularly and avoid leaving water in the humidifier when you are not using the humidifier.
You should also check other sources of excess moisture in your home, such as leaking water pipes to eliminate the cause of excess humidity in your home.
