Heating, air conditioning, and refrigeration mechanics and installers—often referred to as HVACR technicians—work on heating, ventilation, cooling, and refrigeration systems that control the air quality in many types of buildings. 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. When working on air conditioning and refrigeration systems, technicians must follow government regulations regarding the conservation, recovery, and recycling of refrigerants. This often entails proper handling and disposal of fluids. A growing number of HVACR technicians receive postsecondary instruction from technical and trade schools or community colleges that offer programs in heating, air conditioning, and refrigeration. These programs generally last 6 months to 2 years and lead to a certificate; or in some cases, an associate’s degree.