Musty or moldy odor from supply vents when AC runs

Safety first: Turn OFF power to the indoor unit before accessing the coil. Wear gloves and a mask when cleaning moldy areas.

• Step 1 – Inspect coil and pan: Remove access panel and visually inspect the evaporator coil and drain pan for slime or mold.
• Step 2 – Clean coil: Use a non-acidic, no-rinse evaporator coil cleaner approved for HVAC use. Follow label directions.
• Step 3 – Disinfect pan and drain: Clean the pan with a mild bleach solution and flush the drain line.
• Step 4 – Improve filtration: Install a quality filter with appropriate MERV rating and replace regularly.
• Step 5 – Humidity control: Use a dehumidifier if indoor humidity remains high.