What is a likely cause if an air conditioning system runs constantly but does not cool efficiently?

When an air conditioning system runs constantly but fails to cool efficiently, one likely cause is restricted return air or a dirty evaporator. The evaporator coil is fundamental to the cooling process, as it absorbs heat from the indoor air. If the coil is dirty, it can impede heat absorption, causing the system to work harder without achieving the desired cooling effect. Similarly, restricted return air hinders the system’s ability to circulate air properly, leading to inefficient cooling.

This situation can cause the compressor to run longer to try to compensate for the lack of airflow, resulting in increased energy consumption and potential system stress. It is crucial to ensure that both the evaporator is clean and the return air pathways are unobstructed for optimal performance of the HVAC system.

While other factors such as high humidity, overcharged refrigerant, or a faulty thermostat can contribute to cooling inefficiencies, the presence of restrictions in airflow or a buildup of dirt on the evaporator is a primary reason for constant operation without effective cooling.