Heating, Ventilation & Air Conditioning (HVAC) refers to the systems used to control the temperature, humidity, cleanliness, and air circulation in buildings. HVAC systems are designed to maintain indoor air quality by providing the right amount of air, at the right temperature, and with the right amount of humidity. HVAC systems can also be used to control air flow, air distribution, and air filtration, to reduce energy consumption and improve air quality. HVAC systems are essential for the comfort, safety, and health of building occupants.