Hospital operating rooms must meet one of the most complex set of control requirements of any indoor environment, if acceptable performance is to be achieved. The overall objective of this research project was to identify and demonstrate control strategies that could reduce energy requirements while not producing deleterious effects on the environmental quality within the operating room.The objective was achieved through an extensive literature search in which more than 1400 citations were referenced, through the development of mathematical and biophysical models, and through analysis of data obtained in two existing operating rooms with different system performance characteristics.