Heating is the process of raising the temperature of an enclosed space, while HVAC (Heating, Ventilation, and Air Conditioning) is a system that provides heating, cooling, ventilation, and air quality control for a given space. Heating systems typically use a furnace to generate heat, while HVAC systems use a combination of components such as a furnace, air conditioner, and air handler to provide heating, cooling, and air quality control. HVAC systems are more complex and provide more control over the temperature and air quality of a space than heating systems.