A Heating, Ventilation and Air Conditioning (HVAC) Technician is responsible for installing, maintaining, and repairing heating, ventilation, and air conditioning systems in residential and commercial buildings, including diagnosing malfunctions, troubleshooting issues, performing repairs, and ensuring proper system functionality by adhering to safety regulations and manufacturer guidelines; often requiring them to work on various components like furnaces, air conditioners, ductwork, thermostats, and ventilation systems.