Noise from heating, ventilation, and air conditioning (HVAC) systems: A review of its characteristics, effects and control

While Heating, Ventilation, and Air Conditioning, HVAC, systems are essential for maintaining optimal indoor environmental conditions for habitation and occupational activities, their operational noise presents a significant challenge to occupant well-being and performance. HVAC noise, characterized by its dominance in the lower frequency spectrum, originates from mechanical components such as motors and fans, as well as turbulent airflow within ductwork. This continuous, low-frequency noise, LFN, can be demonstrably more disruptive and induce greater psychophysiological stress than intermittent, higher-frequency noise transients associated with system cycling. This paper examines the detrimental effects of HVAC noise on diverse populations, including residential occupants, students, and office workers, synthesizing recent research findings on its impact on comfort, concentration, cognitive function, and work performance. Chronic exposure to HVAC noise has been correlated with elevated stress levels, sleep difficulties, heightened fatigue, increased frustration and anxiety and diminished productivity. Furthermore, studies suggest that HVAC noise can negatively impact cognitive performance in students, impairing attention focus, and potentially memory consolidation. This paper reviews the existing literature on noise generated by various types of HVAC systems and the technical methodologies employed for its measurement and assessment of its impacts on occupants. Legislation in certain countries provides regulatory frameworks to control exposure to HVAC noise. The review highlights the critical importance of leveraging advancements in smart materials and adaptive control technologies to develop more comprehensive noise mitigation strategies in HVAC system design. The primary objective of reducing HVAC noise is to foster healthier, more productive, and comfortable indoor environments.