What is a common symptom of a refrigerant leak?

A common symptom of a refrigerant leak is ice buildup on the evaporator coil. When there is insufficient refrigerant in the system, it cannot absorb heat effectively. As a consequence, the temperature of the evaporator coil drops, and moisture in the air can freeze on the coil, leading to frost or ice accumulation. This scenario not only indicates a refrigerant leak but also can negatively impact the overall efficiency and performance of the HVAC system.

Other symptoms such as inefficient heating, high humidity levels, or unpleasant odors can arise from various issues within an HVAC system, but they are not specifically indicative of a refrigerant leak. Inefficient heating may point to problems with the heating elements or airflow, high humidity might suggest issues with the dehumidification process, and unpleasant odors could originate from mold or mechanical failure, unrelated to refrigerant levels. Thus, the prominent indicator of a refrigerant leak affecting the performance of the system is indeed ice buildup on the evaporator coil.