How do you calculate cfm of ahu?

To calculate the CFM (cubic feet per minute) of an Air Handling Unit (AHU), you can use the formula: CFM = (Airflow Velocity in feet per minute) x (Cross-sectional Area of the duct in square feet). Measure the airflow velocity using an anemometer and the cross-sectional area by measuring the duct dimensions. Alternatively, if you know the total cooling capacity of the AHU in BTUs and the temperature difference across the unit, you can use the formula: CFM = (BTU/hr) / (1.08 x Temperature Difference in °F).