Do Humidifiers Cause Mold?

A rising awareness about how our environment can impact our health has been reflected in a boom in the number of people buying humidifiers for their homes. The Covid-19 pandemic was also a driver, as humidifiers became a tool to mitigate the spread of respiratory illness, while also helping to alleviate symptoms.

Humidifiers can be beneficial to provide relief from a range of health concerns, including eczema, chesty colds, blocked sinuses, and sore throats. They’re also claimed to help sleep; especially to ease a blocked nose or sore, dry throat if you’re suffering from a cold or cough. Although there is debate over whether humidifiers should be used by people with asthma, since too much humidity can aggravate the condition.

Balancing humidity levels

So, while humidifiers bring many advantages, as the saying goes: too much of anything can be a bad thing. Increased humidity in your home can also create the perfect conditions for the micro-organisms that cause mold to thrive, bringing a whole host of other problems.

Michael Rubino, a mold and air quality expert, podcaster and environmental wellness advocate, is also founder of HomeCleanse – a company focused on ending the worldwide health epidemic caused by poor air quality and toxic indoor environments. He says that to prevent mold from forming while using a humidifier, you need to find a balance. “Do not let the indoor humidity rise above 35-50%. Some species of mold can grow in 60% humidity, so the goal is to keep it below that threshold.”

Conversely, you also need to ensure that the humidity doesn’t drop too low. Rubino states that having too little humidity in your home can trigger adverse health reactions, and can also damage your home. It can cause shrinkage in items made from wood, from floors to furniture to musical instruments, which can result in warping and cracking.

How to find the right model of humidifier

In order to ensure the right levels of humidity, Rubino advises that you invest in a humidifier that’s suitable for the size of your room “so that it doesn’t oversaturate the air”. Placement within the room is important, too: “Keep it away from porous materials such as carpeting and fabric furniture, and make sure that it has a hygrometer and humidistat, which will turn the machine off when it reaches the ideal humidity level.”

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Keeping your humidifier clean

Another key tip from our expert is to keep your humidifier clean. “Opt for a machine with a filter to help eliminate small contaminants such as mold spores,” he says. This filter can be removed, as can cartridges in some models, for regular and thorough cleaning.

Begin by unplugging your device, then follow the instructions for cleaning set out by the manufacturer of your model, since each brand’s humidifier will differ. Some cleaning professionals suggest using vinegar, as opposed to abrasive cleaners that can cause damage. It’s best to use soft brushes and soft cloths for best results.

You should regularly empty and clean out the water storage tank, since this is the perfect environment in which spores can form. Some manufacturers suggest this is done daily, while a thorough clean of the entire unit is on a weekly basis. Any removable parts should be soaked for half an hour in either white vinegar or a vinegar/water solution and then thoroughly dried.

“Keeping the machine clean is key to helping avoid microbial growth inside the machine,” says Rubino. “If this happens, your humidifier will end up blowing mold spores and fragments around the room, lowering indoor air quality. Some species of mold also produce microscopic toxins called mycotoxins, further adding to the contamination within your home,” he adds.

Note that where mold grows, bacteria might also thrive. A more common issue with impeller or “cold mist” humidifiers, or those that use ultrasonic technology to create steam, the presence of bacteria can lead to illness, especially in people with asthma and allergies. “Mold spores and bacteria combined can lead to unwanted exposure [to illness] and increase the chances of microbial growth developing elsewhere in the home. This is the reason it’s best to opt for a humidifier that’s easy to clean,” suggests Rubino. If you’re using a humidifier in your home, you’d be wise to regularly check for mold and get rid of any you find.

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Getting the balance right

Do your research to discover the type of humidifier that’s best for your home – for example, if you have young children then steer clear of humidifiers that release steam that could scald. Consider carefully the capacity of the model, so that it fits the space you have.

Pick the right unit and adopt a regular cleaning schedule thereafter and you’ll be able to enjoy the health benefits of a humidifier without worrying about the spread of micro-organisms.