What size duct work do you need for a 3 ton unit?

For a 3-ton HVAC unit, the recommended duct size typically ranges from 12 to 14 inches in diameter for round ducts, or about 8 to 10 inches in width for rectangular ducts, depending on the design and layout of the system. The exact size may vary based on factors such as the length of the duct runs, the number of bends, and the overall airflow requirements. It's essential to perform a proper load calculation and consult local building codes to ensure optimal performance and efficiency.