Health care facilities serve a uniquely vulnerable population exposed to an elevated risk of health, fire, and safety hazard. The health care sector is one of the largest segments of the U.S. economy (17% of U.S.GDP) and the average hospital uses 2.5 times the amount of energy as other commercial buildings, adding up to 836 trillion Btu or $5 billion annually, based on Department of Energy (DOE) data.