Hospitals account for nearly 5% of the total energy use in the United States each year. The average 200,000 ft2 facility spends about $13,600 per bed, or roughly $680,000 annually, on energy costs. Why so much? Operating twenty-four hours a day, thousands of employees, patients, and visitors cycle through campus buildings daily. Additionally, hospitals maintain high ventilation rates to lessen the risk of microbial contamination; the conditioning requirements of this outdoor air represents significant energy usage. Lastly, the use of sophisticated imaging equipment, electronic health record systems and other operations generates heat that must be compensated for via the site’s cooling load.