What is the effect of excessive frost on the evaporator?

Excessive frost accumulation on the evaporator coils can lead to reduced heat transfer efficiency. This occurs because frost acts as an insulating layer on the coils, which inhibits the proper transfer of heat between the refrigerant inside the evaporator and the air passing over the coils. As frost builds up, it restricts airflow as well, further decreasing the amount of heat that can be absorbed by the refrigerant. This results in less effective cooling, causing the system to work harder to maintain desired temperatures, ultimately leading to inefficiency and increased energy consumption.

In contrast, options that suggest increased efficiency, high humidity, or increased superheat do not accurately reflect the detrimental impact of excessive frost on the evaporator's performance. A well-maintained evaporator should have minimal frost, ensuring optimal heat transfer and efficient operation.