True or False: Higher indoor humidity levels result in less air temperature difference across the evaporator coil.

The assertion that higher indoor humidity levels result in less air temperature difference across the evaporator coil is true. When indoor humidity levels increase, the moisture content in the air rises. This additional moisture affects the evaporator coil's performance, specifically, how the coil absorbs heat from the air.

As humidity levels go up, moisture condenses on the evaporator coil. This process of dehumidification requires heat energy. Consequently, the coil has to work harder to remove heat because it is dealing with latent heat (energy used to remove moisture) in addition to sensible heat (energy used to change air temperature). As a result, the temperature difference between the air flowing over the coil and the temperature of the refrigerant in the coil tends to decrease when humidity is higher.

In essence, with elevated humidity levels, the cooling capacity of the evaporator coil is partially utilized for dehumidification rather than purely for cooling, leading to a smaller temperature difference across the coil.

The other options do not accurately reflect the relationship between humidity and the temperature difference across the evaporator coil. Higher airflow might influence the effectiveness of heat exchange, but it doesn't directly negate the impact of humidity. The type of refrigerant is generally more relevant to system efficiency and specific heat