What is likely to happen in the summertime in a humid environment if a section of metal ductwork is uninsulated in an unconditioned space?

In a humid environment during summertime, uninsulated metal ductwork located in an unconditioned space will likely experience condensation. This occurs because the warm, moist air from the surrounding environment comes into contact with the cooler surface of the metal duct. The metal, being uninsulated, cannot maintain a higher temperature than the surrounding moist air, leading to the temperature of the duct surface dropping below the dew point of the air. When this happens, moisture from the air condenses on the surface of the duct, resulting in droplets forming on the ductwork.

This scenario can lead to various issues such as increased humidity in the duct system, potential mold growth, and water damage, which can impact both the air quality and the structural integrity of the building. Proper insulation of ductwork is essential to prevent this condensation by keeping the duct surface temperature above the dew point and reducing the risk of moisture accumulation.