Heat Pump Noise: Scoping Overview of Emission Characteristics and Systematic Review of Human Effects

The aim of this work is two-fold: to characterize air-source heat pump (ASHP) noise emissions and to systematically evaluate the scientific evidence regarding non-auditory health effects, thereby assessing the technology's current and future public health impact.

The primary component is a PRISMA-guided systematic review on noise impact. Utilizing a population-exposure-outcome framework, eight bibliographic databases were searched for English and German records. Of 501 identified records, 26 reports (covering 25 unique studies) met eligibility criteria. Risk of bias (RoB) was evaluated across four domains-sampling, measurement validity, confounding, and reporting-while overall evidence certainty was assessed using established frameworks. A secondary, non-systematic scoping overview was conducted to characterize ASHP noise emissions based on technical databases and literature.

ASHP sound emissions are highly variable, contingent upon specific components (fan and compressor), radiation angles, and operating conditions. The systematic review identified 10 laboratory studies, 14 observational surveys, and one prognosis study, predominantly published since 2011. While results indicate a non-negligible potential for annoyance, concentration impairment, and self-reported sleep disturbance, the overall certainty is low. This is attributed to small samples, methodological heterogeneity, and high RoB in critical domains. Preliminary data provide tentative indications that ASHP noise may exhibit higher annoyance potential than road traffic noise at equivalent sound pressure levels.

Despite increasing research interest, the evidence base for long-term health impacts of heat pump noise remains limited and of low certainty. Future research should prioritize large-scale longitudinal studies and comparative investigations with other environmental noise sources to inform evidence-based noise control.