Abstract: Methods and systems for operating a Heating, Ventilating and Air Conditioning (HVAC) system in accordance with one of a plurality of operating modes. The plurality of operating modes include one or more of a health mode, an energy savings mode and a balanced mode. In some cases, the operating modes include two or more energy saving modes. The currently operating mode is selected based on the current operating conditions of the building and the desired goals of the building operator. The goals can include, for example, reducing energy usage, reducing pathogen risks, increasing air quality and/or a combination of these goals. In some cases, the operating modes are autonomously controlled. In some cases, the operating modes are manually controlled.