moldy air conditioner fins

How to Prevent Mold Growth in Your HVAC System

Mold growth is easily recognizable by its musty, dirty “gym sock” odor, and you certainly don’t want that smell coming from your air ducts. Unfortunately, mold growth can occur in HVAC systems, particularly if dust is allowed to build up in moisture-prone areas. Below, we’ll explain where and how mold tends to grow in HVAC systems and what you can do to prevent it.

Where Does Mold Grow In Heating & Cooling Systems?

There are three primary locations where mold growth typically occurs in HVAC systems: the air conditioner’s indoor unit, the drain pan, and the ductwork. These locations can foster mold growth by providing the spores what they need: moisture, food, and warmth. Food for mold can be something as simple as dust, which is why it can pay to keep your system clean.

How Does Mold Grow In Heating & Cooling Systems?

To understand how mold growth occurs in your HVAC system, you’ll need some basic knowledge about how your system works.

Your air conditioner’s indoor unit contains a part called the evaporator coil. The evaporator coil cools air and also extracts moisture from the air it cools. High-efficiency furnaces extract moisture from the air as well. When everything is working correctly, that moisture (condensate) drips down into a drain pan and exits your home through the condensate drain line.

However, the condensate drain line can get clogged with dust and grime, which causes the moisture to drain slowly. This creates a damp environment in your drain pan. If there is enough warmth and enough dust buildup, mold can start growing in your drain pan and on other parts of your indoor unit, like the blower wheel.

Mold can also start to spread inside your air ducts if there are leaks in the ductwork. Leaks can allow mold spores inside, along with dust, heat, and moisture--the three things mold needs to grow.

How to Prevent Mold Growth in Heating & Cooling Systems

There are several ways to help prevent mold growth in your HVAC system:

  • Use an air filter with a MERV 8 rating or higher, and replace it regularly. This efficiency level is high enough to capture most mold spores at your return vent.
  • Keep up with routine maintenance. During the appointment, the technician will be able to flush out your condensate drain line to prevent clogs and get rid of dust build-up that could lead to mold growth and decrease your unit’s efficiency.
  • Invest in duct cleaning. Dust, dander, hair, and other pollutants can coat your ductwork’s interior over time, lowering your indoor air quality and providing a food source for mold spores.
  • Install a UV air purifier. These indoor air quality systems destroy harmful biocontaminants like germs and mold spores by breaking down their DNA, rendering them unable to reproduce while also keeping them out of your HVAC system and indoor air.

At Premier Indoor Comfort Systems, LLC, our home comfort specialists can assist you with anything from your home’s temperature to its humidity level to its indoor air quality. Call us today at (770) 749-7667 or contact us online for help with your HVAC system. We offer 24-hour emergency service to customers throughout the Greater Atlanta area & Western North Carolina.

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