Round duct is cylindrical metal tubing used to distribute conditioned air throughout HVAC systems, available in diameters from 3 to 24 inches. Round ducts are fabricated from galvanized steel, aluminum, or stainless steel and represent the most aerodynamically efficient ductwork option. They provide superior airflow characteristics compared to rectangular ducts and reduce friction losses by 10 to 20 percent.
Performance and Installation
Round ducts generate less noise during operation due to their smooth internal surfaces and optimal shape for laminar airflow. They require fewer support hangers than rectangular ducts and are faster to install, reducing labor costs. Internal velocities of 600 to 900 feet per minute minimize noise while maintaining adequate capacity.
Applications and Advantages
Round ducts work well for long-run distributions and high-velocity applications requiring maximum efficiency. They are commonly used in commercial HVAC systems and high-performance residential installations. Proper sealing with mastic tape and sealant ensures airtightness, maintaining efficiency ratings above 90 percent in properly installed systems.