Study on human response to the cumulative impact of air source heat pump noise
Within the International Energy Agency (IEA) Technology Collaboration Programme Heat Pumping Technologies (HPT) Annex 63 on “Placement Impact on Heat Pump Acoustics”, a task group is addressing the psychoacoustics of Air Source Heat Pumps (ASHPs). A joint listening experiment was conducted across seven European countries and ten organisations to evaluate the cumulative impact of multiple ASHPs in residential back gardens. This study investigates noise annoyance responses to a sample of sounds of ASHPs in scenarios with varying numbers of operating units, and under varying operating conditions, considering three different noise barrier types and two background noise sound pressure levels. The experiment comprised three parts: (1) assessment of a single ASHP in various operating states, combined with two background noise levels and all three noise barrier types; (2) analysis of paired ASHPs with varying distances, operating state combinations, and inter-unit noise barrier types; and (3) evaluation of configurations with three to six ASHP units, simulating realistic residential layouts. In each part, participants provided annoyance ratings using a standardised scale. The study aims to identify how factors such as the number of operating units, their spatial arrangement, operating conditions, and the presence of noise barriers influence noise annoyance. The results provide valuable insights for the development of psychoacoustic models for estimating ASHP noise annoyance, and for the acoustic planning and design of heat pump installations in high-density urban areas.