Which of the following is a key indicator of proper airflow in an air conditioning system?

A key indicator of proper airflow in an air conditioning system is the temperature difference between supply and return air. This temperature differential, often referred to as temperature split, provides vital information about how efficiently the system is operating. When the system is functioning correctly, there should be a consistent temperature difference—typically between 15 to 20 degrees Fahrenheit—between the supply air (air coming out of the vents) and the return air (air that is drawn back into the system).

This difference indicates that the air conditioning system is effectively removing heat from the space and providing adequate cooling or heating as needed. A significant deviation from this expected range can suggest issues with airflow, such as blockages in ductwork, insufficient insulation, or problems with the blower fan.

The other options, while they may provide some insight into system performance, are not primary indicators of airflow. Noise levels may suggest mechanical issues or air movement but do not directly correlate to airflow efficiency and may vary based on the system's design. The color of the refrigerant is irrelevant to airflow performance and more pertinent to refrigerant type and system operation, while the age of the equipment might indicate wear or maintenance needs, but does not serve as a direct measure of current airflow.