What material is most commonly used for making HVAC sheet metal ducts?

Galvanized steel is the most commonly used material for making HVAC sheet metal ducts due to its durability, cost-effectiveness, and resistance to corrosion. The galvanization process involves coating the steel with a layer of zinc, which provides additional protection against rust and wear, making it suitable for the varying conditions found in many HVAC systems.

The strength of galvanized steel also allows for the fabrication of ductwork that can withstand high pressures and endure the mechanical stresses associated with airflow. Additionally, it can be easily shaped and formed into the required duct sizes for installation in residential and commercial buildings.

While aluminum is lightweight and resistant to corrosion, it is generally more costly and is often used in specific applications where weight savings are critical. Plastic ducts may be used in certain scenarios, particularly for ventilation systems, but they do not have the same structural integrity as metal ducts and may not be suitable for all environments. Copper, although an excellent conductor of heat, is rarely used for ductwork due to its high cost and is more commonly found in refrigerant lines and other plumbing applications.