There are three distinct types of muscles: skeletal muscles, cardiac or heart muscles, and smooth (non-striated) muscles.
HVAC technicians are responsible for the installation, maintenance and repair of heating, ventilation and air conditioning (HVAC) systems. As an HVAC technician, your job duties may include inspecting existing systems and making recommendations intended to improve the efficiency and/or safety of that system's performance. HVAC-R techs may also work on refrigeration systems.
These certifications are required before they can start to professionally perform repair, service, maintenance or chemical disposal. However, given the fact that HVAC technicianâs duties vary depending on the job he wants to pursue, it does not necessitate one to take all four types of exams.