Why Setting Your AC Fan to “Run” Can Cause Mold
During warm months, many homeowners keep their AC units running constantly to stay comfortable. A common setting is “auto fan mode,” which turns the fan on only when cooling is needed. Some, however, choose the “on mode,” which runs the fan nonstop—even when the AC isn’t actively cooling.
Pros and Cons of Running the Fan Constantly
Running the fan all the time can help circulate air and improve indoor air quality. But it also has downsides you should know about.
How Constant Fan Operation Encourages Mold Growth
When your fan runs continuously, it keeps air moving inside the house. This can raise indoor humidity, creating a perfect environment for mold. Mold loves moist, humid places with poor air circulation. The fan can cause condensation on cool surfaces like walls, ceilings, and floors, especially if your home lacks good ventilation or has leaks.
Health Risks from Mold
Mold spores travel through the air. When they land on damp surfaces, they attach and grow quickly. Mold can cause health issues such as respiratory problems, allergies, and skin irritation.
How to Prevent Mold When Using Your AC Fan
To stop mold growth, keep your home’s humidity between 30% and 50%. Use a hygrometer to monitor levels. Make sure your home has good ventilation by opening windows or installing exhaust fans near moisture sources. Consider switching your fan setting to “auto” instead of “run.”
Clean and replace your air filters regularly. Also, schedule yearly maintenance for your AC unit to keep it running properly.
Signs of Mold and What to Do
Look out for musty smells, black spots, or discoloration on walls or ceilings. If you see these signs, act quickly to remove mold and stop it from spreading. Maintain good airflow, keep your home clean, and ensure your AC is in good condition.