Space External Cooling Load Assumptions Climate Zone Example City Cooling Load (Btuh/sf) Airlfow required to meet external load at 74 °F space temperature and 55 °F supply air temperature (CFM/sf) 1 Miami, FL 17.76 0.87 2 Midland, TX 14.34 0.70 3 Vance AFB, OK 10.92 0.53 4 St. Louis, MO 7.50 0.37 5 Omaha, NE … Continue reading HVAC Rule of Thumb CFM/sf