Hospitals are the 2nd most energy intensive building type in the US and especially high consumers of natural gas. Many existing Healthcare facilities were designed with the primary goal of patient safety and occupant comfort, and energy consumption was often ignored. As a result, a large percentage of the existing healthcare building stock have a higher than necessary energy use intensity (EUI). Inefficient and poorly managed control systems, constant volume ventilation and over ventilation, inaccurate or nonexistent equipment schedules, and poor building envelope are some of the reasons for increased energy consumption in our hospitals. Based on a recent IAQ based ventilation study in a US hospital, it is estimated that healthcare facilities are using 30-40% more natural gas than is necessary to meet IAQ standards for safety and occupant comfort. 

The first step for any hospital decarbonization plan is to reduce the internal loads including reheat energy and improve energy efficiency. Reducing the amount of heat a building needs to operate will reduce scope 1 emissions caused by onsite combustion of natural gas. This first step focuses on improving building controls by performing retro commissioning and implementing smart control sequences so the facility’s systems are only operating during occupied hours and taking advantage of lower load conditions with appropriate minimum ventilation setpoints, temperature and pressure resets, and heat recovery. Constant volume systems use excessive cooling and reheat energy to meet the temperature setting in the space. Variable air volume conversions can be done simply with a low payback while reducing up to 30% of the natural gas consumed by reducing boiler heating energy and 25% of a building’s electricity usage by reducing fan and chiller energy. Displacement ventilation is another effective strategy in reducing over ventilation and excessive reheat energy. An efficient building envelope is critical for decarbonizing hospitals. Avoiding unwanted infiltration of outdoor air or exfiltration of building heat as well as avoiding heat loss or gain through the walls and roof will help prevent additional loads to be put on the central plant systems. This will be especially important when heat recovery systems like heat recovery chillers are utilized to replace gas-fired boilers to generate building heat.