Why your AC system is a health hazard waiting to happen
The arrival of summer means longer days, outdoor barbecues, and, unfortunately for most homeowners, the perfect conditions for a hidden health threat that’s been quietly growing in homes across America. While most people focus on obvious problem areas like bathrooms and basements, there’s one location that often gets overlooked until it’s too late.
Homeowners are usually pretty good about checking the obvious spots for mould and moisture issues, says Jeff Berzolla, home maintenance expert at Instant Roofer, a platform that uses AI-powered roof calculators to deliver accurate roofing estimates nationwide. But there’s one area that gets completely ignored, and it’s one of the most dangerous places for moss and mould to take hold.
That location? Your air conditioning unit, vents, and ductwork. The combination of moisture, darkness, and organic debris creates the perfect breeding ground for moss and mould growth that can seriously impact your family’s health. Berzolla explains why this overlooked area has become such a pressing concern for homeowners nationwide.
Why your AC system is a health hazard waiting to happen
Air conditioning systems create the perfect storm for moss and mould growth. When warm, humid air meets the cool surfaces of your AC unit and ductwork, condensation forms. Add in dust, pollen, and organic debris that gets sucked through your system, and you’ve created an ideal breeding ground.
Most people think their AC is just cooling their home, but it’s circulating whatever’s growing inside those ducts throughout every room. If you’ve got moss or mould in there, you’re pumping spores directly into the air your family breathes.
The problem gets worse during peak summer months when AC systems run constantly. The continuous cycle of moisture and organic matter creates conditions that allow dangerous microorganisms to flourish unchecked.
The hidden health impact
The health consequences can be severe, especially for children, elderly family members, and anyone with respiratory conditions. Mould spores circulating through your home’s air supply can trigger asthma attacks, cause persistent coughing, and lead to chronic fatigue.
I’ve seen families dealing with mysterious health issues for months, only to discover the source was right above their heads in the ductwork. The scary part is that by the time you notice symptoms, the contamination has usually been spreading for weeks or even months.
Some people experience headaches, skin irritation, and difficulty concentrating. In extreme cases, certain types of mould can cause more serious respiratory infections that require medical treatment.
Where to check for problems
Start with your outdoor AC unit. Look for any green growth around the base, on the coils, or near the drain pan. Check your indoor vents for dark spots, discolouration, or any fuzzy growth around the edges.
Don’t forget about your ductwork access points, typically found in basements, attics, or utility closets. If you can safely access these areas, use a flashlight to look for any visible growth or water damage.
Four ways to prevent and fix the problem
Berzolla lists four tips to avoid falling ill due to an unclean AC unit.
1. Change Your Filters Regularly
Replace your AC filters every 30-60 days during peak usage. Dirty filters restrict airflow and create moisture buildup that encourages growth.
2. Keep Your Outdoor Unit Clean
Clear away leaves, grass clippings, and debris from around your outdoor unit. Trim back vegetation to ensure proper airflow and prevent organic matter from accumulating.
3. Monitor Your Drain Pan
Check that your AC’s condensate drain isn’t clogged. Standing water in the drain pan is a major red flag for potential mould growth.
4. Schedule Professional Cleaning
Have your ductwork professionally cleaned every 3-5 years, or immediately if you suspect contamination. This isn’t a DIY job. Professional equipment can reach areas you simply can’t access safely.
Don’t wait until you have a major problem
Most homeowners wait until they have a major problem before they start paying attention to their AC system, but by then the damage is usually already done. The good news is that catching mould early is pretty straightforward if you know what to look for.
Trust your nose first; if you’re getting a musty, earthy smell when your AC kicks on, that’s your biggest warning sign. You might also notice unusual sounds like rattling or whistling that weren’t there before, which could indicate blockages from growth or debris. And, if you can see dark spots or fuzzy growth around your vents, you need to act immediately.
The key is being proactive rather than reactive. A simple monthly walk-around of your outdoor unit and a quick sniff test when your system starts up can save you thousands in repairs and protect your family’s health. Don’t ignore the warning signs – your lungs will thank you later.
Instant Roofer is a platform founded in 2022 that uses AI-powered roof calculators to deliver instant, accurate roofing estimates nationwide. By analysing over 129 million U.S. homes, it provides tailored cost estimates in seconds without requiring signup or exposing users to spam. Homeowners choose their preferred material (asphalt, metal, cedar, or solar) and instantly see local, real-time pricing and top-rated contractor options.
