HVAC is the abbreviation for Heating, Ventilation and Air Conditioning. According to Wikipedia, HVAC is the "technology of indoor and automotive environmental comfort".

While an HVAC unit is what performs all the heating, ventilation and air conditioning through convenient regulation of temperature and climate inside a room or building. To better understand how an HVAC works - it simply processes warm air to the interior of the building and creates an acceptable air quality and temperature at the most efficient cost for consumers.

Heating

Heating is the process of bringing of heat to different parts of the building, specifically to ducts and piping to efficiently distribute air on building spaces.

Ventilating

Ventilating is the process of controlling air temperature to make it acceptable for a certain space, as well as removing several components mixed with the air like smoke, moist, dust, odors, etc.

Air Conditioning

Is the process of removing heat or simply cooling the air by using refrigerant components like ice.

How Much Would An HVAC Cost?

The cost of having an HVAC unit depends on several factors like size of the home, and the components that will be use to for the HVAC unit.