Why is over-insulating ductwork in unconditioned spaces detrimental?

Over-insulating ductwork in unconditioned spaces can indeed trap condensation and lead to mold growth. When ducts are excessively insulated, it can create a temperature differential that causes moisture in the air to condense on the surface of the ducts. This moisture can become a breeding ground for mold, especially in environments that might already be prone to humidity. Mold growth not only poses health risks but can also lead to structural damage and reduced system efficiency.

In contrast, moderate insulation levels help prevent energy loss without significantly increasing the risk of condensation. This balance is crucial to maintain optimal airflow and system performance, as well as to ensure the longevity of the ductwork and the health of the indoor environment.