Air Conditioning Repair Certification (ETI) Practice Exam

A dirty evaporator significantly impairs the efficiency and cooling capacity of an air conditioning system. The evaporator is responsible for absorbing heat from the indoor air, and when it is dirty, it cannot effectively transfer heat. The accumulation of dirt and debris creates an insulating barrier that reduces the surface area available for heat exchange, resulting in a lower ability to absorb heat.

As the evaporator struggles to remove heat, the overall cooling capacity diminishes, leading to inadequate temperature reduction in the conditioned space. Consequently, the system has to work harder to reach the desired indoor temperature, which further decreases its energy efficiency. This can lead to increased energy consumption and higher utility bills, as well as potential wear and tear on system components due to stress from operating inefficiently over time.

In contrast, other options, such as increased airflow, frequent compressor cycling, and lower humidity control, may be associated with different issues but do not directly relate to the fundamental impact of a dirty evaporator on cooling efficiency and capacity. The correct choice highlights the critical role that maintaining a clean evaporator plays in ensuring optimal performance in air conditioning systems.