"HVAC (heating, ventilating, and air-conditioning) refers
to the equipment, distribution network, and terminals that provide
either collectively or individually the heating, ventilating,
or air-conditioning processes to a building...."
"HVAC systems have a significant effect on the health, comfort,
and productivity of occupants. Issues like user discomfort, improper
ventilation, and poor indoor air quality are linked to HVAC system
design and operation and can be improved by better mechanical
and ventilation systems. ..."
and Cooling Systems, Building
Technologies Program, Office
of Energy Efficiency & Renewable Energy, U.S.
Department of Energy