What is a common symptom of low refrigerant in an HVAC system?

A common symptom of low refrigerant in an HVAC system is reduced cooling capacity along with ice formation on the evaporator coil. When the refrigerant levels drop, the system struggles to absorb heat from indoors, resulting in inadequate cooling. As the evaporator coil fails to reach the proper temperature due to insufficient refrigerant, condensation can accumulate and freeze on the coil. This ice buildup can further hinder the system's ability to cool effectively, creating a cycle of decreasing performance.

The other symptoms presented in the choices do not accurately represent issues associated with low refrigerant levels. Increased energy efficiency typically stems from a well-functioning system, whereas low refrigerant would lead to higher energy consumption due to the system working harder to reach the desired temperature. Consistent heating performance is unrelated, as it pertains to heating rather than cooling issues. Finally, while excessive noise from the compressor can result from various problems, it is not a defining indicator of low refrigerant. Overall, recognizing reduced cooling capacity and ice formation is crucial for diagnosing and addressing refrigerant issues promptly in an HVAC system.