Heating and air-conditioning systems control the temperature, indoor air quality, and humidity in buildings. Refrigeration systems allow us to transport and store food, medicine, and other perishables. Heating, air conditioning and refrigeration systems are often referred to collectively as HVAC.
HVAC mechanics, installers, and technicians diagnose and correct problems with a client's system, install new systems, or clean and maintain equipment. This requires a good understanding of electronics, testing equipments (such as voltmeters), and mechanical repair, including pipe-fitting.
Technicians usually specialize in either installation or in maintenance and repair, although they can do both. Some technicians have more specific areas of expertise, such as commercial refrigerator installation. Smaller companies and independent contractors tend to do both installation and repair, because business is cyclical.
In the summer, clients need new a/c systems, and in the winter, new heating systems. In the off-seasons, technicians repair and service systems.
Technicians who buy or handle certain refrigerants have to pass a test and be licensed. Refrigeration technicians must conserve, recover and recycle CFCs and HCFCs, which, if released into the atmosphere, cause ozone depletion. Working conditions can be hazardous and uncomfortable, but the pay generally makes up for this. Most companies offer good health care and other benefits packages. Many technicians work forty hours or more per week. Some technicians are on-call and work evenings and weekends.
There are a few certifications available. One is the Air Conditioning Excellence Program, administered by North American Technician Excellence (NATE).