The most important maintenance task that will ensure the efficiency of your air conditioner is to routinely replace or clean its filters. Clogged, dirty filters block normal airflow. With normal airflow obstructed, air that bypasses the filter may carry dirt directly into the evaporator coil and impair the coil’s heat-absorbing capacity. Lower your air conditioner energy consumption by 5% to 15% when you replace a dirty, clogged filter.

The air conditioner’s evaporator coil and condenser coil collect dirt over their months and years of service. A clean filter prevents the evaporator coil from soiling quickly. You should minimise dirt and debris near the condenser unit. Your dryer vents, falling leaves, and lawn mower are all potential sources of dirt and debris. Cleaning the area around the coil, removing any debris, and trimming foliage back at least 2 feet (0.6 meters) allow for adequate airflow around the condenser.

The aluminium fins on evaporator and condenser coils are easily bent and can block airflow through the coil. Air conditioning wholesalers sell a tool called a “fin comb” that will comb these fins back into nearly original condition.

Occasionally pass a stiff wire through the unit’s drain channels. Clogged drain channels prevent a unit from reducing humidity, and the resulting excess moisture may discolour walls or carpet.