Air conditioning encompasses a range of functions that work together to create a comfortable and healthy indoor environment. It involves conditioning and delivering air, as well as providing heating and cooling through central plants or rooftop units. Air conditioning also regulates temperature, humidity, air movement, cleanliness, sound levels, and pressure differentials within predetermined limits. Whether for occupant comfort or product processing, the term HVAC&R (heating, ventilating, air conditioning, and refrigerating) is commonly used to represent the combined processes, reflecting the industry’s historical development of individual components.