State Licensure

• State licensure is often required to work legally as an HVAC technician in the majority of states in the U.S. BLS reports that the state licensing exams usually require you to have studied and become familiar with subjects such as electrical code and have HVAC-specific knowledge of operating systems.
  
  

EPA

• The Environmental Protection Agency (EPA) reports that all technicians who work on HVAC systems and may release refrigerants into the atmosphere must complete training to become licensed to handle and remove refrigerants. The tests for EPA certification are specific to the type of appliances you will work on. Also, a universal certification is available for technicians licensed to work on all types of appliances.
  
  

Types

• To become certified by the EPA, you must complete a CORE test containing information on ozone depletion and the Clean Air Act. Type 1 classification is for small appliances, with testing on recovery techniques and refrigerant safety. Type 2 and 3 classification is for high-pressure and low-pressure appliances and includes subjects such as recovery techniques, leak detection and safety.