HVAC components regulate vehicle cabin air temperature, humidity, and quality. Systems are integrated throughout the vehicle, including engine compartment, dashboard, and passenger area. Key elements include the compressor, condenser, evaporator, and expansion valve, forming the refrigerant loop for cooling and heating. Blend door actuators control airflow direction and temperature mixing. Modern systems increasingly utilize electronic controls, variable displacement compressors, and cabin air filtration for optimized performance and air quality.