How to Prevent Mold in Your HVAC System During the Fall Season

Fall in Southern California often brings cooler temperatures, cloudy skies, and higher humidity especially near the coast.

These conditions, while mild compared to other states, can still lead to excess moisture building up inside your HVAC system. And where there's moisture, there's a risk of mold.

Mold in your HVAC system not only creates unpleasant odors, but it can also pose health risks and lower indoor air quality. Here’s how to prevent mold from taking hold in your system this fall.

Change Air Filters Regularly

One of the easiest and most effective ways to prevent mold is by keeping your filters clean. Dirty filters trap moisture and restrict airflow, creating a perfect environment for mold spores. Replace your filters at least once every 1-3 months, especially if your system has been running frequently over the summer.

Keep Ducts and Vents Clean

Dust and debris inside your ductwork can hold moisture and encourage mold growth. Fall is a great time to have your air ducts inspected and cleaned if necessary. Look for signs like musty smells, visible mold near vents, or increased allergy symptoms indoors.

Check for Moisture Around Units

Both your indoor and outdoor units should remain dry. Check the condensate drain line and drain pan to ensure they’re not clogged or leaking. Water pooling around any part of the system is a red flag.

Use a Dehumidifier If Needed

In particularly humid parts of SoCal, a whole-home or portable dehumidifier can help keep indoor humidity below 50% the threshold where mold tends to thrive. Consider installing one if you’ve previously had mold issues or if your home feels damp during fall.

Keep Vents Unblocked

Proper airflow helps regulate temperature and humidity. Make sure furniture or curtains aren't blocking your HVAC vents. Also, don’t close off too many rooms in your home, as that can create pressure imbalances and trap moisture.

Perform Seasonal Maintenance

Professional maintenance includes inspecting coils, pans, blowers, and drain lines all potential mold hotspots. If you're not already performing fall HVAC maintenance, now is the time.

Mind the Dryer Vents

Don’t forget about appliances like your dryer. Dryer vents can trap moisture and release it into the air if clogged. Cleaning them in the fall helps prevent excess humidity indoors.

What to Do If You Spot Mold

If you notice visible mold or persistent musty odors, it’s time to call in a professional. Mold inside ductwork or near coils can be difficult to clean on your own and may require remediation.

Staying proactive in the fall helps ensure a clean, healthy, and efficient HVAC system throughout the season. If you need a fall inspection or suspect mold in your unit, call us at (714) 465 1135 or book a visit online today.