Heating, air conditioning, and refrigeration mechanics and installers typically do the following:

• Use blueprints or design specifications to install or repair HVACR systems
• Connect systems to fuel and water supply lines, air ducts, and other components
• Install electrical wiring and controls and test for their proper operation
• Inspect and maintain customers' HVACR systems
• Test individual components to determine necessary repairs
• Repair or replace worn or defective parts
• Determine HVACR systems' energy use and make recommendations to improve their efficiency

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 HVACR technicians are trained to install, maintain, and repair heating, air conditioning, and refrigeration systems, many focus their work on installation, maintenance, or repair. Some technicians specialize in one or more specific aspects of HVACR, such as radiant heating systems, solar panels, testing and balancing, or commercial refrigeration.

When installing or repairing air conditioning and refrigeration systems, technicians must follow government regulations regarding the conservation, recovery, and recycling of refrigerants. The regulations include those concerning the proper handling and disposal of fluids and pressurized gases.

Some HVACR technicians sell service contracts to their clients, providing periodic maintenance of heating and cooling systems. The service usually includes inspecting the system, cleaning ducts, replacing filters, and checking refrigerant levels.

Other workers sometimes help install or repair cooling and heating systems. For example, on a large air conditioning installation job, especially one in which workers are covered by union contracts, ductwork may be installed by sheet metal workers, electrical work by electricians, and pipework by plumbers, pipefitters, and steamfitters. Boiler systems sometimes are installed by a boilermaker. In addition, home appliance repairers usually service window air conditioners and household refrigerators.

HVACR 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.