HVAC (pronounced h-vack or spelled out) stands for Heating, Ventilating and Air Conditioning. The three functions of heating, ventilating, and air-conditioning are closely interrelated. All seek to provide thermal comfort, acceptable indoor air quality, and reasonable installation, operation, and maintenance costs. HVAC systems can provide ventilation, reduce air infiltration, and maintain pressure relationships between spaces. Your heating and air technician goes by the name of HVAC contractor, and can provide heating repair expertise.