Air conditioner runs but does not cool the room effectively; supply air feels only slightly cooler than room air.

Safety first: Turn off power before cleaning coils or filters.

Steps to try:

• Clean filters: Wash or replace all air filters.
• Clean coils: Gently clean indoor and outdoor coils with a soft brush and appropriate coil cleaner.
• Check doors and windows: Close windows and minimize heat sources (ovens, direct sun without blinds).
• Measure temperature drop: After 15 minutes of operation, measure air temperature at return and supply. A typical drop is 8–12°C. If much lower, refrigerant or mechanical issues may exist.

When to call a technician: If cleaning and load reduction do not restore performance, have a technician check refrigerant charge and system pressures.