The importance of focusing on energy optimization in existing buildings is crucial to reducing energy consumption and greenhouse gas emissions. In the U.S., existing buildings represent 85-90% of entire building stock (75+ billion sqf t). Buildings are responsible for an estimated 40% of U.S. primary energy use, 72% of electricity consumption, 39% of carbon emissions, and1 13.6% of potable water consumption.
Existing buildings typically have aging building systems and infrastructure that present opportunities for energy optimization, yet they often have limited capability or lack of building management systems. In addition, a significant number of existing buildings are historic buildings, presenting additional obstacles with respect to historic preservation during energy retrofit projects.