What is the minimum required height for a duct installed above a crawl space floor?

The minimum required height for a duct installed above a crawl space floor is 4 feet. This requirement is established to ensure adequate clearance for maintenance, prevent damage to the ducting, and to enhance airflow efficiency. When ducts are positioned too low, they may be more susceptible to damage from foot traffic or objects stored in the crawl space. Additionally, maintaining this height helps minimize the risk of condensation forming on the ducts, which could lead to moisture problems and mold growth in the crawl space. Furthermore, a height of 4 feet allows for easier access for inspections and repairs, contributing to the overall longevity and effectiveness of the HVAC system. This standard is adhered to in various building codes and best practice guidelines within the HVAC industry.