Just in time for summer, the major appliance manufacturer Midea recalled 1.7 million of its popular window air conditioners because of a design flaw that made certain units prone to mold growth — a potentially dangerous issue that can lead to respiratory health risks.
Even if you don’t own one of the recalled models, the possibility of mold lurking in your air conditioner can be cause for concern as summer heats up.
What Are Allergies?
Mount Sinai ENT Erin McGintee, MD, explains.
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How Does Mold Grow on Air Conditioners?
All air conditioners are prone to mold. That’s because mold — a fungus found naturally both outdoors and indoors — needs moisture and a food source like dust (which is collected by AC unit filters) in order to grow.
Research suggests that the damp surfaces of an air conditioner can be breeding grounds for microorganisms like fungi. The amount of microbes like mold growing on an AC unit’s cooling coils can vary based on factors like climate and the efficiency of the device’s filters.
Air conditioner mold growth may be inevitable in some parts of the United States where the climate is often hot and humid, says Jordan Peccia, PhD, a professor of chemical and environmental engineering at Yale University in New Haven, Connecticut.
“In humid areas like the eastern U.S., a lot of water will condense on the air-conditioning unit’s cooling coils and potentially get onto other components like the fans, so that’s where one would have the highest risk for mold growth,” says Dr. Peccia, an expert in molecular environmental biology who’s conducted research on fungal and bacterial growth on air-conditioning units.
This differs from regions where the climate is hot and dry, like Arizona or certain parts of California. Because there’s not as much condensation flowing through the air conditioner, researchers haven’t noticed as many microbes brewing on AC units there, Peccia notes.
How Can You Tell if There’s Mold in Your Air Conditioner?
Mold grows when tiny mold spores — which aren’t visible to the naked eye — float through the air and land on wet or moist surfaces.
Sometimes, mold growth is hidden. When it is noticeable, common signs of mold growth in, on, or around an air conditioner include.
Discolored, fuzzy-looking, or slimy patches on a surface area
Water staining or warping damage
Musty odor
How Does Mold Make You Sick?
Some people are allergic to mold. But exposure to mold can trigger symptoms and irritation whether you have a mold allergy or not — and they may crop up right away, or later on. Mold exposure can lead to the following common symptoms:
Itchy, irritated, or watery eyes
Runny nose
Nasal congestion
Headache
Sneezing
Itchy skin, particularly around the nose, mouth, and lips
Rashes
Dizziness
For people with asthma, mold exposure may prompt or exacerbate respiratory symptoms like shortness of breath, wheezing, and a tight feeling in your chest.
In addition, children, older adults, and people who have respiratory conditions may experience worse health effects from mold exposure.
How to Clean Up Mold From Your AC Unit
If there already is mold growing in your air-conditioning unit, it’s important to clean it up and fix the moisture issue so that the mold doesn’t grow back. Here are some steps to get started:
Scrub clean and dry completely. Use a mixture of soap and water to wipe the affected surfaces, then ensure they’re dried completely.
Check the AC unit manufacturer instructions. Depending on where the mold is located, keep in mind that you may need to safely disassemble some of the unit’s pieces according to the instruction manual — or consult a specialist.
Protect yourself from additional exposure. Wear gloves, a mask, and goggles while cleaning to limit your exposure to mold — and check with a healthcare provider first if you have asthma or another underlying health condition that compromises your immune system.
Can You Prevent Mold From Growing Inside Your AC?
It’s not possible to completely eliminate all mold or mold spores indoors. But you can prevent or minimize its growth by controlling moisture levels in your home and in the air conditioner itself.
“The easiest way to keep your home air-conditioning unit free of mold growth is to drain away the water as much as you can, and install a better filter,” says Peccia. Better drainage will help keep the inside of the AC unit drier, he adds, which prevents a moldy environment.
Experts recommend the following tips:
Keep up with filter maintenance. Replace air conditioner filters according to the manufacturer’s recommendations, typically every 60 to 90 days.
Control humidity. Maintain indoor humidity levels below 60 percent, and use a dehumidifier if needed.
Stay dust-free. Keep your home and space around the air conditioner dusted, and try an air purifier to remove excess particles and microbes from the area.
Consider upgrading. Check the efficiency of your air conditioner’s air intake filter and upgrade to a higher-quality filter if needed.With a better filter, excess dust gets trapped and won’t be able to feed mold growth in the air conditioner — even if there is some moisture present, Peccia notes.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Emily Kay Votruba has copyedited and fact-checked for national magazines, websites, and books since 1997, including Self, GQ, Gourmet, Golf Magazine,Outside, Cornell University Press, Penguin Random House, and Harper's Magazine. Her projects have included cookbooks (Padma Lakshmi's Tangy Tart Hot & Sweet), self-help and advice titles (Mika Brzezinski's Know Your Value: Women, Money, and Getting What You're Worth), memoirs (Larry King's My Remarkable Journey), and science (Now You See It: How the Brain Science of Attention Will Transform How We Live, Work, and Learn, by Cathy Davidson). She started freelancing for Everyday Health in 2016.
Cristina Mutchler is an award-winning journalist with more than a decade of experience covering health and wellness content for national outlets. She previous worked at CNN, Newsy, and the American Academy of Dermatology. A multilingual Latina and published bilingual author, Cristina has a master's degree in Journalism from the E.W. Scripps School of Journalism at Ohio University.
