Can Humidifiers Cause Mold?

When it comes to keeping our homes and bodies warm, humidifiers are often used. However, improper maintenance can cause these devices to become useless and contribute to the development of airborne microbes that can cause chronic health complications.

A dirty humidifier can cause mold to form and become airborne contaminants that can harm people with respiratory conditions like asthma. This is why the EPA and the Consumer Product Safety Commission warned that consumers should avoid using humidifiers.

Yes, humidifiers can cause mold growth, but that’s when they are used unregulated that they end up raising the level of moisture indoors to one that easily supports such growth (usually above 55 percent relative humidity).

When the humidifier is run, it then disperses these microorganisms far and wide across the perimeters of the room where it is used, and the organisms can then easily find a home on moist cotton, moist wooden furniture, or walls and window sills with condensation built upon them.

From there, it’s only a matter of days before the presence of any living mold becomes known in those areas.

Can Humidifiers Cause Mold?

Humidifiers can cause mold growth if not maintained and cleaned properly. When the humidifier is left running continuously, it can create excess moisture that increases the humidity levels and result in mold growth. The usage of water with less mineral content can prevent microbial growth.

The mold growth problem can be especially pronounced when an individual lives in an area where the species of mold require a relatively low moisture content in the air to begin activities, and also when the temperature indoors is warm rather than cold which is optimal for most fungus to activate and begin reproduction.

This article will explain why a humidifier can cause mold growth and how it can be used to prevent this issue from happening.

Related: Can Humidifiers Make You Sick?

How a Humidifier Can Contribute to the Growth of Mold

Since you can use a humidifier to fight against mold and other microbes, if you don’t use it properly, it can lead to the opposite effect. 

Rare portable humidifiers without a control humidistat are most likely the ones to cause such problems since they require manual monitoring by a human observer which isn’t going to be ideal.

Even portable humidifiers with built-in humidistats can also produce unreliable results since a vast majority of them are rarely accurate to the settings on the dial and can be off by as much as 10 to 20 percent.

This, in a cold, warm, tropical, or humid climate, can cause the humidifier to raise humidity level to far more than required and thus cause condensation on elements like walls and window sills which can easily harbor mold growth.

1. Regular Cleaning

The air humidifiers can cause mold growth is if they are left uncleaned for an extended amount of time which ends up creating film or scum that acts as breeding grounds for these microorganisms.

Although humidifiers are useful, they can be very harmful to the environment if they are not cleaned. Also, keeping a clean filter and reservoir can help prevent the growth of harmful bacteria and mold.

It is also important to thoroughly clean and sanitize your humidifier. Also, make sure that most components are properly dried.

2. Monitor The Humidity Levels

When using a humidifier, make sure that the humidity levels are far below 55%.

This level should be within 30% to 50% for your homes and offices. A digital hygrometer is also required to monitor the humidity in your home.

Types of Humidifiers That Affect Mold Growth

There are generally two ways in which humidifiers can cause mold growth indoors. First is when they’re left to run unnecessarily, for long, or at excessive moisture settings which will cause an increase in the humidity levels around the house (or room where they are installed).

These organisms are then dispersed during humidification which is the perfect time and condition for them to find a residence in various materials around the house, especially wet and damp surfaces like wet laundry cloth or damp carpets.

The first point applies equally to all humidifiers that aren’t controlled by an automated system, and as for the second, it’s exaggerated mostly on the cold mist humidifiers such as ultrasonic, evaporative, and the impeller types that generally contain a compartment for standing water.

Cold mist humidifiers are the biggest culprit when it comes to mold growth for the following reason. They create cold mists and disperse them into the air which is excellent for spewing into the air, whatever microorganisms have already bred inside the standing water.

When molds are dispersed from contaminated standing water into the air, they usually cling to surfaces that are reminiscent of the medium they just left, which are warm, moist areas that are able to provide them food to eat.

The typical examples are building materials made up of cellulose or plant fibers such as moist wooden walls, furniture, and cotton curtains.

Related: Are Humidifiers Good for You?

How to Prevent Mold Growth

In the first case from above, it’s very simple. Only use a humidifier when you really need it, because even those having humidistat can rarely keep exacting settings. That’s how humidifiers are meant to be used after all, not all year round.

Put humidifiers at the correct moisture setting while taking into consideration the current conditions of the room. This will help maintain the humidity at an acceptable range which is somewhere between 25 percent and 40 percent.

For the first case, just use a humidifier when you need it. Also, since humidistat can’t keep exacting settings, it should only be used once a year.

Taking into account the current conditions of the room, set the humidity range to between 25 and 40 percent. You can also confirm and adjust the humidity within the four walls using a hygrometer.

If you’re anything like Daniele Del Nero — which means you’re quickly aroused by the sight of millions and millions of molds consuming the load-bearing structures of any apartment, then turn on the humidifier during winter until you transform into a breathing braise of your own perspiration.

For the second case, which is that of humidifiers with standing water, the solution is simple. Here’s what to do.

1) Clean the humidifier

This will prevent the accumulation of scum on the surface of humidifiers that can cause the growth of microorganisms. It is also important to note that the manual contains instructions that will teach you how to clean them.

If you can’t access your owner’s manual, then follow these simple steps to properly clean your humidifier. Hydrogen peroxide is a powerful and effective cleaner that can remove dirt and build-up on the surface of humidifiers. To get the most out of your humidifier, make sure to thoroughly rinse and dry before using.

To maintain the longevity of your humidifier, regularly replace the water supply with fresh water. Once the tank has been empty, thoroughly clean the base, sides, and cap using a soft cloth or a toothbrush. This will help remove any impurities or build-up on the surface.

Follow the manufacturer’s instructions on how to replace the filter or cartridges. Also, it’s best to store them away since they can be easily discarded.

Related: The Humidifier That Is Easy To Clean

2) Use water with less mineral content

Too much water contains minerals that can cause allergic reactions and make the air contaminated with particles look like fine dust. Also, these minerals can contribute to the growth of mold and other microorganisms.

However, this method will remove varying amounts of minerals. You can also check their effectiveness by observing how long the residue lasts.

When using a humidifier, make sure that it’s always changed on a regular basis to prevent the accumulation of minerals. Also, be sure to check the labels to make sure that the water has been treated to remove the minerals.

3) Eliminate any dampness near the humidifier

To prevent mold growth, make sure that the area around the humidifier is free of any dampness. This includes the windows and wall panels that have been subjected to ventilation. To regulate humidity, turn the volume down.

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