It is important to provide unrestricted airflow to the outdoor unit. Leaves, trash or shrubs crowding the air conditioner or heat pump cause the unit to work harder and use more energy. Also remove any debris that may have collected around the unit.
The outdoor coil on an air conditioner or heat pump can sometimes become obstructed by grass clippings, leaves, dust, etc. If this happens, using a garden hose, gently run water over the coil, removing unwanted obstructions.
Ground shifting or settling can cause an air conditioner or heat pump to sit in an uneven position. If this happens, re-level the unit to make sure water/moisture drains from the cabinet properly.