What is the minimum insulation value required for a residential return air duct in a sealed crawlspace in Wilmington, North Carolina?

In a sealed crawlspace in Wilmington, North Carolina, the minimum insulation value required for a residential return air duct is technically none required. This is due to the building codes and standards applicable to conditioned spaces, where sealed crawlspaces are treated as part of the conditioned area when properly insulated and sealed.

In such cases, the ducts can operate effectively without additional insulation, as the surrounding environment is controlled for temperature and humidity levels. Furthermore, duct insulation requirements can vary based on occupancy and specific building practices as per local codes, which may not impose insulation mandates for ducts in these specific setups.

This context leads to the conclusion that, in a sealed crawlspace scenario, it is acceptable to have return air ducts without any insulation value. Therefore, the assertion that there is no minimum insulation value required is consistent with these considerations.