Simple AC Units Maintenance Starts With Airflow A practical routine for ac units maintenance is to check the air filter each month and clean or replace it when dirty. Keep indoor vents open and clear leaves and other debris from the outdoor unit. Turn off power before cleaning any accessible parts. Before the cooling season, schedule a professional check-up for the coils, drain, electrical parts, and refrigerant system. I’m Adam Wettach, and years of hands-on plumbing work ha