Heating and air conditioning-often called HVAC technicians-work on heating, ventilation, and cooling systems that control the temperature and air quality in buildings. Duties Heating and air conditioning mechanics typically do are the following: * Use blueprints or design specifications to 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 businesses and other buildings. HVAC technicians are trained to maintain heating and air conditioning systems. HVAC technicians use many different tools. For example, technicians 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 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.