Why does my AC unit smell musty and how can I get rid of the odor?

Your AC unit may smell musty due to mold or mildew growth in the system. To get rid of the odor, you can try cleaning or replacing the air filters, cleaning the evaporator coils, and using a mold and mildew cleaner in the unit. It's also important to ensure proper ventilation and humidity control in your home to prevent future musty smells.