This paper is the first of three papers on the development of experimental performance models of variable air volume fan powered terminal units. Tests were conducted on both parallel and series fan powered terminal units. Data from these tests were used to develop empirical models of airflow, power, and leakage of both parallel and series fan power terminal units. These models are suitable for use in annual energy use models of variable air volume systems in commercial buildings. This paper provides a description of the experimental apparatus, the terminal units, and measurements for airflow and power. Both 8 in. (203 mm) and 12 in. (304 mm) primary air inlet terminal units from three manufacturers were evaluated.Units: Dual