Extensive field measurements indicate that the external static pressures (ESPs) in residential air distribution systems are well above the requirements in equipment rating and testing standards. An excess ESP directly affects blower airflow rates and power draws. In addition, it has indirect impacts on system efficiencies, capacities, and operating hours because of the ESP effects on the system airflow rates. Hence, the objective of this study is to investigate how ESPs affect the residential heating and cooling energy use in hot climates. Experimental results on the aerodynamic and cooling performance of unitary equipment were integrated with a public-domain building simulation model to estimate the annual heating and cooling energy use at different ESP settings.