HVAC (heating, ventilating, and air conditioning; also heating, ventilation, and air conditioning) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a sub discipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. Refrigeration is sometimes added to the field's abbreviation as HVAC&R or HVACR, or ventilating is dropped as in HACR (such as the designation of HACR-rated circuit breakers).
HVAC is important in the design of medium to large industrial and office buildings such as skyscrapers and in marine environments such as aquariums, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors.
Ventilating or Ventilation (the V in HVAC) is the process of "changing" or replacing air in any space to provide high indoor air quality which involves temperature control, oxygen replenishment, and removal of moisture, odors, smoke, heat, dust, airborne bacteria, and carbon dioxide. Ventilation removes unpleasant smells and excessive moisture, introduces outside air, keeps interior building air circulating, and prevents stagnation of the interior air.
Ventilation includes both the exchange of air to the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types
The three central functions of heating, ventilation, and air-conditioning are interrelated, especially with the need to provide thermal comfort and acceptable indoor air quality within reasonable installation, operation, and maintenance costs. HVAC systems can provide ventilation, reduce air infiltration, and maintain pressure relationships between spaces. The means of air delivery and removal from spaces is known as room air distribution
HVAC technicians work in residential homes, schools, hospitals, office buildings, or factories. Their worksites may be very hot or cold because the heating and cooling systems they must repair may not be working, and because some parts of these systems are located outdoors. Irregular hours and working in cramped spaces are common.
How to Become a Heating, Air Conditioning Mechanic and Installer
Because HVAC systems are increasingly complex, employers generally prefer applicants with postsecondary education or those who have completed an apprenticeship. Some states and localities require technicians to be licensed.
Heating, air conditioning, and refrigeration mechanics and installers—often called HVAC technicians—work on heating, ventilation, cooling systems that control the temperature and air quality in buildings.
Heating, air conditioning, and refrigeration mechanics and installers typically do the following:
- Use blueprints or design specifications to install or repair HVAC systems
- Connect systems to fuel and water supply lines, air ducts, and other components
- Install electrical wiring and controls and test for proper operation
- Inspect and maintain customers’ HVAC systems
- Test individual components to determine necessary repairs
- Repair or replace worn or defective parts
- Determine HVAC systems’ energy use and make recommendations to improve efficiency
- Travel to worksites
Heating and air conditioning systems control the temperature, humidity, and overall air quality in homes, businesses, and other buildings. By providing a climate-controlled environment, refrigeration systems make it possible to store and transport food, medicine, and other perishable items.
Although HVAC technicians are trained to both install and maintain heating, air conditioning, and refrigeration systems, many focus on either installation or maintenance. Some also may specialize in certain types of HVAC equipment, such as water-based heating systems, solar panels, or commercial refrigeration.
HVAC technicians use many different tools. For example, they often use screwdrivers, wrenches, pipe cutters, and other basic hand tools when installing systems. Technicians also use more sophisticated tools, such as carbon monoxide testers, voltmeters, combustion analyzers, and acetylene torches to test or install system components.
When working on air conditioning and refrigeration systems, technicians must follow government regulations regarding the conservation, recovery, and recycling of refrigerants. This includes the proper handling and disposal of fluids and pressurized gases.