Performed A/C tune-up on a Rudd heat pump system and checked the electrical, mechanical and performance systems of the unit. Filter was replaced recently and is clean. Cleared, cleaned, flushed and treated the drain line. Cleaned the exterior of the air handler and washed the outdoor coil. I found that the indoor coil is dirty. The system is currently working but I did inform him that if the coil gets dirtier it will restrict airflow and freeze over. I presented the homeowner with repair options. No other issues were found. The system is operational at this time.