Why is it not advisable to oversize an A/C system?

Oversizing an air conditioning system can lead to ineffective humidity removal, primarily because a larger unit cools the space too quickly. When an A/C system overshoots the required cooling capacity, it doesn't run long enough to dehumidify the air properly. Humidity is removed from the air during the cooling process, as the evaporator coils cool down, causing moisture to condense. If the system cycles on and off too quickly, it fails to achieve this essential dehumidification, resulting in a home that feels clammy and uncomfortable.

The other issues associated with oversizing, such as reduced energy efficiency, higher costs, and increased noise, are certainly significant, but the potential for poor humidity control is particularly critical in establishing a comfortable indoor environment. Maintaining balanced humidity levels is essential for both comfort and the prevention of mold growth, making it vital to select an appropriately sized A/C system.