Air humidifier

Air humidifier with a remote control at the side.


One age-old question homeowners ask is: do humidifiers cause mold?

The short answer is: yes, they could.

During dry winter and summer months, portable humidifiers are used to increase humidity in homes to fight seasonal air dryness. Humidifiers even have therapeutic benefits; they are used to prevent dry-skin irritation and ease symptoms of a common cold.

In dry climates, dry air could worsen respiratory problems; therefore, humidifiers become household necessities. However, humidifiers are known to harbor toxic molds. Even the 

Environmental Protection Agency (EPA) and U.S. Consumer Product Safety Commission (CPSC) warn that dirty humidifiers are precursors to household mold contamination

The humidifier tends to accumulate mold and mold spores inside its water tank, fan blades, and vents. You may even risk inhaling these spores.

Moreover, while humidifiers can help manage moisture in your home air—excessive moisture isn’t acceptable. 

Respiratory disease

A moist environment is a breeding ground for mold. Inside the humidifiers is also a cozy incubator for these molds.

The CPSC warns about “humidifier fever”— a lung inflammation illness with flu-like symptoms caused by bacteria in the humidifier. 

Inhaling bacteria or mold spores due to a dirty humidifier may lead to asthma and other respiratory issues.

According to this University of Utah case study, kids are more vulnerable to lung problems when they inhale “white dust” from dirty humidifiers, which is a powdery accumulation of mineral deposits inside the machine’s reservoir.

Monitoring the humidity

Clean your unit

Cleaning your humidifier often with distilled water is an excellent way to avoid mold accumulation.

Using tap water (mineralized water) may increase bacterial growth inside the humidifier.

By continuously cleaning your machine, you can prevent you and your family from inhaling mold spores. 

The EPA says you should wash your humidifier at least once in three days, or even every day, if possible.

To clean mold deposits, use a solution of warm (distilled) water and everyday dish soap to clean the sides of the water reservoir.

Using the right cleaning agent is vital too. Using agents that contain harsh chemicals may cause more respiratory problems. 

Additionally, keep changing the filters often. 

Fill the tank with distilled water

Protecting your health should involve monitoring the kind of water you fill your tanks with. If the filled water is of poor quality, it could cause many problems.

The EPA and CPSC say you should stop using tap water and start using distilled water if you want to stop inhaling potentially toxic microorganisms.

Manage the humidity levels

eletronic humidifer

Electronic humidifier i

Apart from proper cleaning of your humidifier and filling its tank with distilled water, managing the moisture around the machine is critical.

Setting the humidifier too high may create a mist of moisture around the machine. This is a significant problem as wetness allows for mold and mold spores to thrive. When your humidifier is set to high, and it starts misting, turning it down is the right thing to do. 

A digital humidifier is excellent for monitoring the humidity level. 

The recommended average relative humidity level ranges from 30 to 50 percent.

Anything below 30 percent may lead to dry eyes, skin, and bloody noses.

Above 50 percent may lead to excessive moisture in the air, which encourages the spread of mold.

Asides keeping your household humidity at or below 50 percent, you can purchase an indoor humidity monitor if you don’t own a digital machine.

In the end, keeping humidity levels at a low and comfortable level will reduce the spread of mold in your home. 

EPA says that “steam vaporizer” or “evaporative” humidifiers are likely to emit microorganisms than “cool-mist” or “ultrasonic” humidifiers. 


Keep humidifier away from certain surfaces 

Never set up your humidifier near porous objects or surfaces like fabric or wooden tables. Moisture from the machine can seep into these objects or surfaces—creating a breeding ground for mold. Older pieces of wooden furniture are even more vulnerable. 

Have you noticed that the furniture around your home feels moist or sticky? Your humidifier may have been cranked up. Lower humidity to prevent mold problems.

Use preventive measures 

Taking preventive measures at high humidity levels should help stop mold contamination, especially on your floorboards and other porous surfaces.

Cleaning your floors with a borax or bleach solution and consistent vacuuming will prevent fungal build-up.

At high humidity, insulate surfaces that cause condensation, like water pipes. Moisture often forms around cold pipes and leads to corrosion as well as mold contamination. Insulate the pipes in your home to prevent these problems.

Traditional methods, like spray foam insulation, or using reusable insulation blankets with hydrophobic aerogel could do the job.

Another preventive measure is leveraging proper ventilation and ventilation devices to rooms prone to collect moisture in your home.

Likewise, investing in an air conditioning unit may help lower temperatures, which reduces the spread of mold. While mold can still develop at low temperatures, their mold spores are less active when your home is cool.

Final note

Humidifiers are essential in making your home comfortable by preventing dryness and its related health issues.

But when you set your humidifier too high in dry air, the chances of condensation increases, allowing for moisture to pool around your house. Wetness settles, creating a fertile ground for mold growth.

Managing humidity levels and proper cleaning of your machine are the best practices to avoid mold problems. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to  .

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