Return Duct Size For 2.5 Ton

For a 2.5-ton unit, we use 16 inch round returns ducts or 1812, 2010, and 268 rectangular returns ducts. These ducts can facilitate at least 1,000 CFM airflow. To calculate the equivalent duct size, we can convert the rectangular duct size into equivalent diameter and then work backward to find the equivalent length and width.

Enter your AC size or airflow get both square and round return duct sizes. The return air duct size calculator estimates the cross-sectional size of a return opening from the air conditioner tonnage and the selected design face velocity. Use our free return duct size calculator to find the correct return air duct diameter, rectangular dimensions, filter size, and grille free area for balanced HVAC ventilation.

For instance a 2.5 ton system (Approximately 400 CFM per ton) would require (2) 14 flexible return ducts or (1) very short flexible 18 duct to move the 1000 CFM required by the 2.5 ton system. Enter CFM, get the exact round or rectangular duct size in seconds. Free ductulator with velocity, friction loss, return air, and trunk line sizing.

Use our handy return air duct size calculator or charts below to help you determine the correct return air vent size for your home. These charts and calculators are intended to calculate the return air duct only. Return air duct size for 1-5 ton ACs is 14 to 22 for round ducts and 13x12 to 32x12 for rectangular ducts.

Use the return air duct size calculator below for accurate dimensions required for your air conditioner or heat pump. A 2.5 ton system requires about 1,000 CFM (cubic feet per minute) of airflow. If your ducts are undersized or leaky, the system will underperformeven if the AC unit itself is efficient.

For a 2.5 ton split unit, ensure at least 400 CFM of return air. Two 12-inch round ducts typically provide about 400-450 CFM combined, but long duct runs and flex ducts reduce airflow due to friction and bends.