When inspecting a central air conditioning system, what is the expected temperature drop across the evaporator on a humid summer day?

The expected temperature drop across the evaporator coil of a central air conditioning system on a humid summer day is typically between 15 to 25 degrees Fahrenheit. This temperature drop occurs because the evaporator coil absorbs heat from the indoor air as the refrigerant within the coil evaporates, cooling the air that circulates through the home.

On humid days, the efficiency of the AC system focuses not only on cooling but also on dehumidifying the air, which can contribute to the noticeable temperature drop. A drop of 15 to 25 degrees allows for effective cooling while also helping to manage humidity levels, providing a comfortable indoor environment.

In conditions where the temperature drop is outside this expected range, it may indicate potential issues with the system, such as low refrigerant levels, airflow restrictions, or problems with the evaporator coil itself.