<div class="section abstract"><div class="htmlview paragraph">Noise induced by the Heating, Ventilation and Air conditioning (HVAC) system inside a vehicle cabin can cause significant discomfort to passengers and, in turn, affect the brand image in a competitive automotive market. HVAC acoustic performance has become more prominent with the ongoing transformation from Internal Combustion (IC) to Electric Vehicle (EV) segments. For this reason, acoustic quality is increasingly prioritized as a key design issue throughout the entire development process of the HVAC system. This paper covers the design synthesis considering air handling unit-induced airborne and structure-borne noise of a dashboard-mounted HVAC system to achieve better NVH refinement inside vehicle while maintaining thermal performance. This study began by analysing HVAC-induced blower motor, impeller, air ducts, vents, and recirculation suction noise from the vehicle level to subsystem level and eventually at the component level. At the subsystem level, major noise source identification and source ranking were carried out with the help of an acoustic camera. This study revealed that the blower unit recirculation suction path, blower motor impeller, and air ducts radiated noise as potential sources causing overall subsystem and vehicle cabin noise to increase. A novel suction path design was developed to improve recirculation suction air rush noise at the subsystem level. Air ducts radiated mid-frequency noise was optimized by developing acoustic air ducts at the subsystem level. At unit level, blower impeller noise improvement was achieved by developing a quiet blower impeller. Finally, all design modifications were implemented on HVAC unit and thermoacoustic performance was evaluated on a production vehicle. The output of this work was development of a cascading methodology, a reduction in 4-5 dB (A) HVAC system noise and a 10% increase in the articulation index of the car. Additionally, the sound quality of HVAC noise was significantly improved by reducing loudness by 5 sones.</div></div>
