HVAC Explained

February 3, 2013.

HVAC is an abbreviation which stands for; heating, ventilation and air conditioning. HVAC represents the mechanics and principles for moving and controlling air through a residential or commercial building. The HVAC system heats air in winter and cools it in the summer while ventilating a building by the exchange of the fresh air outside with the stagnant indoor air.


The basic purpose of a ventilation system is to exchange the air within a building to get rid of dirt, smoke, bacteria, and other unhealthy particles. Ventilation circulates outside air throughout the building, using the heating or air conditioning system to control the air temperature. This is done by a combination of fans, vents and ducts that force interior air out and bring exterior air in. The ventilation system also includes an air filtration system that confines foreign particles and dust.


For heating, a central heating system comes with a system to heat water or air. The heated air or water is dispersed throughout the building via a system of ducts (in a forced-air system) or pipes that deliver steam from a central boiler and pump to a set-up of radiators. The radiators, which are usually installed near windows and other cold points, heat the air primarily via convection, drawing cool up air up through the radiator itself and heating it as it rises.

Air Conditioning.

For air conditioning, the ductwork and forced-air circulation system can also transport cooled air from an air conditioning system. Heat is removed from circulating air through an air handling unit, which is installed within the building. The air conditioning system cycles through a succession of compression, heat exchange, condensation and evaporation, which dehumidifies the air. Fans force the cooled air through ventilators into individual spaces, where temperature is controlled in a series of zones with thermostats.

In Conclusion.

The design and components of heating, ventilation and air conditioning (HVAC) systems vary greatly according to application, particularly among commercial structures. Warehouses, multiple-story office buildings and manufacturing plants each have unique climate control requirements and present the building's engineer or maintenance staff with a distinct set of design, installation and repair challenges.