In HVAC systems, color-coated steel coils (such as PPGI and PPGL) are commonly used for manufacturing air ducts due to their excellent corrosion resistance, durability, and aesthetic flexibility. PPGI is widely used for standard ducting applications, offering a balance between performance and cost, while PPGL, with its superior corrosion resistance, is ideal for systems in humid or corrosive environments, such as coastal areas. These color-coated steel coils not only enhance the longevity of air ducts but also contribute to the system's energy efficiency and performance.