The key parts of an aircon that require regular cleaning include the air filter, evaporator coil, blower fan or squirrel cage, drainage tray and drain pipe, the outer casing of the indoor unit, and the condenser coil and fins of the outdoor unit. The air filter is the component that needs the most frequent attention and can be washed by the homeowner, while the evaporator coil, blower fan, and drainage system require a more thorough cleaning that is best handled by a professional technician using appropriate tools and cleaning solutions. The outdoor condenser unit is often overlooked but accumulates dirt, leaves, and debris over time that reduce its ability to release heat efficiently, making it an important part of any complete aircon cleaning service.