Your Air Conditioner's Coils Might Need Cleaning
Dirty air conditioner coils can lead to various costly and uncomfortable problems in your home. From mold growth to inefficient cooling, the buildup on your system's evaporator or condenser coils can reduce performance and even pose health risks. If you've noticed reduced airflow, higher utility bills, or a musty smell, your AC coils could be the culprit.
If you're wondering how often to clean A/C coils or if dirty AC coils can make you sick, the short answer is this: dirty coils should be cleaned at least once a year, and yes, they can negatively impact your indoor air quality. Mold, bacteria, and dust accumulation can all circulate through your air ducts, triggering allergies or worse.
Let's break down what happens when AC coils are dirty, the signs to look for, and why professional cleaning is essential.
Poor Airflow Through the AC Unit's Coils
Your HVAC system is built to deliver a specific volume of air—measured in cubic feet per minute (CFM)—through your home's ductwork. But when the evaporator coil is dirty, airflow becomes restricted. This forces the system to work harder, resulting in longer run times, uneven cooling, and inflated power bills.
Dirty air conditioner coils can become packed with dust, pet hair, and debris that blocks efficient airflow. Over time, this debris reduces the coil's surface area, limiting the system's ability to absorb and transfer heat. A thorough coil cleaning helps restore airflow and improves your air conditioner's overall performance.
Even if you regularly change your air filters, fine particles can still reach the coils. That's why annual maintenance is a smart investment in both comfort and efficiency.
Iced-Up Evaporator Coil
Another common consequence of dirty AC coils is ice buildup. Here's how it happens:
When warm indoor air passes over the evaporator coil, moisture in the air condenses. That moisture is supposed to drain away, but if the coil is dirty and airflow is reduced, the moisture may freeze instead. Once ice forms on the evaporator coil, it acts as a barrier, trapping even more moisture and creating a cycle that reduces airflow further and accelerates freezing.
Eventually, ice can block the entire coil and prevent air from passing through at all. When this happens, your home may suddenly feel warm, even though the system is running. If you notice ice or frost on your indoor coil or refrigerant lines, shut the system down and call a professional immediately.
Reduction in Cooling Efficiency
Your air conditioner's primary function is to pull heat from your home's air and release it outside. When the evaporator coil is covered in debris, the coil can no longer efficiently remove heat from the air. The result? A sluggish system that takes longer to reach the desired temperature.
This leads to longer cycles and more frequent use, which means increased wear on your system and rising energy bills. You may even notice that your AC runs all day without keeping you comfortable—especially during peak summer months.
Simply put, air conditioner coil cleaning restores heat transfer and allows your AC system to do its job properly. Clean coils help your home cool down faster, save you money, and extend the lifespan of your equipment.
Mold on AC Coils and Indoor Air Quality Concerns
Mold growth is one of the most serious issues tied to dirty air conditioner coils. When dirt and moisture combine, mold and mildew find a perfect place to grow—especially in humid environments like Florida. Black mold on AC coils can become a dangerous issue if left unchecked.
Your evaporator coil is particularly vulnerable because it handles condensation. If that moisture isn't properly drained or the coil remains damp due to reduced airflow, mold can take hold. Once that happens, the spores may begin circulating throughout your ductwork and into your living space.
If you detect a musty smell when the system runs or notice visible mold on evaporator coil surfaces, it's time to call for immediate service. Long-term exposure to airborne mold can trigger allergy symptoms, asthma, and other respiratory issues. This is especially concerning for children, seniors, and those with pre-existing conditions.
Yes, dirty AC coils can make you sick, especially when mold is present. Don't ignore it.
Compressor Damage and Major Repairs
Your AC system's compressor is the heart of the operation. It pumps refrigerant through the system, allowing for heat exchange. However, when dirty coils reduce efficiency, your compressor is forced to work harder and for longer periods of time.
This continuous strain can cause the compressor to overheat. Most modern systems have sensors that temporarily shut the unit down to prevent catastrophic failure. But if the underlying problem—dirty AC coils—isn't addressed, the compressor may continue to cycle on and off until it finally fails.
Replacing a compressor is one of the most expensive AC repairs. Avoid this costly issue by keeping your coils clean and scheduling regular maintenance with an experienced HVAC technician.
How Often to Clean A/C Coils
The best way to avoid all of the issues listed above is to include air conditioner coil cleaning in your annual maintenance routine. At a minimum, have the coils inspected and cleaned once a year, preferably before the cooling season begins.
If you live in a high-pollen area, own pets, or notice frequent dust buildup in your home, you may need more frequent service. A professional technician can inspect your coils inside the house and determine if additional cleanings are necessary.
Changing your air filter every 30–60 days will also help reduce coil contamination. A clean filter traps dust and debris before it can reach your evaporator coil. Use the correct filter size and MERV rating for your system.
What Not to Clean AC Coils With
Thinking about DIY coil cleaning? Think again.
While it might be tempting to handle the job yourself, it's important to know what not to clean AC coils with. Harsh chemicals like bleach, ammonia, or degreaser can damage the coils' delicate fins, potentially void your warranty. Likewise, high-pressure water can bend the aluminum fins and further restrict airflow.
Only use coil cleaning solutions specifically designed for HVAC use—and better yet, call a professional. Certified technicians have access to the proper tools, cleaners, and safety equipment to clean your coils effectively without damaging the system.
Signs Your AC Coils May Need Cleaning
Not sure whether your system needs a coil cleaning? Watch for these signs:
Weak or warm airflow from vents
Increased run time and higher energy bills
Ice on refrigerant lines or the indoor coil
Musty or moldy smells when the AC is on
Unusual system noise or short cycling
Visual buildup on coils (dust, dirt, or mold)
If any of these symptoms sound familiar, don't delay. Ignoring dirty AC coil issues can lead to breakdowns, health problems, and rising costs.
Protect Your Investment with Professional Coil Cleaning
Your air conditioning system is a complicated piece of machinery that needs routine maintenance to operate efficiently. While changing your air filter is something you can (and should) do yourself, cleaning air conditioner coils inside the house is best left to trained HVAC professionals.
If you suspect mold on AC coils, experience reduced airflow, or just want to keep your system in peak condition, call a licensed HVAC company for a thorough inspection and cleaning. Regular maintenance boosts performance, protects your health, improves indoor air quality, and saves you money in the long run
CMB Air is a state-licensed, insured, and bonded company providing AC refrigerator leak repair, AC fan motor, AC condenser repair or replacement, AC circuit control board, AC tune-up and preventative maintenance, evaporator coil, and condenser coil services in Tampa and surrounding areas. Call (813) 447-1443 today!
