The Louisville area typically experiences humid summer weather, and this humidity can easily lead to mildew starting to grow on different parts of your AC system. Constantly smelling mildew whenever your AC is running can be quite unpleasant and may lead you to want to shut the system off and deal with heat instead of the musty smell. Luckily, mildew issues in your AC are typically both easy to overcome and prevent, and today we’re going to look at where and how mildew typically forms and how to stop it from happening.

Mildew on the AC Evaporator Coil or in Your Ductwork

If you smell mildew coming out of your vents, it usually means that mildew is growing either on your AC evaporator coil or somewhere inside your ductwork. The evaporator coil is the component that is most prone to mildew growth. This coil is located within your HVAC air handler, and it is what works to remove both heat and humidity from the air.

When your AC is on, cold refrigerant constantly flows through the coil and works to absorb heat from the warm air being forced over it. The difference in temperature between the warm air and the cold coil also means that much of the moisture in the air condenses onto the coil, which is how your AC also helps to reduce indoor humidity.

This combination of moisture on the coil and the warm air blowing over it creates perfect conditions for mildew and even bacteria to start growing. Having your AC professionally maintained every year can help to prevent this issue, as the technician will always fully clean the coil.

Still, if you frequently have mildew issues, you may want to consider either a whole-home dehumidifier or a coil-sanitizing UV light unit. A dehumidifier will work to lower your home’s humidity level to reduce the risk of mildew and other issues caused by high indoor humidity, whereas a UV light unit will emit ultraviolet rays that stop the propagation of mildew and bacteria that may form on the coil.

If your ductwork is damaged and leaks air or the ducts in your attic or crawl space aren’t insulated, condensation can start to form in the ducts and lead to mildew. This is why you should always have your ductwork inspected annually to ensure that it is free from these issues.

Mildew Growing Inside the AC Condensate Drain System

If you smell mildew or musty smells any time you go near your air handler, it is almost always related to your AC condensate drain system. The condensate drain system is what captures the water that collects on the coil and funnels it into your sewage system or directly outside the home. If you have a high-efficiency condensing furnace, then it is most likely tied into the same condensate drain system that the heating unit uses.

The water that forms on the evaporator coil first drips into a drain pan and then runs through a series of condensate drain lines. These lines usually empty into a floor drain, but they can also run outside if your air handler is in the attic or anywhere other than the basement.

As with the evaporator coil, the combination of warm air and moisture can easily lead to mildew growing inside the drain pan and the drain lines. Over time, the mildew can even build up to the point where the system gets clogged, and water starts to leak out.

Annual AC maintenance will help to prevent this issue as the technician will clean the drain pan and make sure the lines aren’t clogged. Pouring vinegar into the drain pan occasionally can also help to reduce the growth of mildew. Another option is to use drain pan tablets, as these are specially formulated to ensure that mildew and bacteria can’t start to grow.

Louisville’s AC and Heating Experts

If you need AC maintenance or any other heating or cooling service, the experts at Element Air LLC have you covered. We service and repair all types and brands of air conditioners and furnaces, and we also specialize in AC and furnace installation and replacement. If your home has issues with high indoor humidity or poor air quality, we also offer a range of indoor air quality equipment and services. For more information or to schedule an appointment, give us a call today.

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