The primary aim with Annex 51 is to further increase the acceptance of heat pumps (as air-to-water, water-to-air, air-to-air and brine-to-water units) for comfort purpose with respect to the noise and vibration emissions.

A second focus is placed on increasing knowledge at different levels (manufacturers, acoustic consultants, installers, legislators). To reach this goal, first different reasons to reduce sound emissions depending on countries (legislation), locations and applications have to be gathered and understood. The main influencing factors to the acoustic signature of these units will be identified. Collecting and combining research results in these fields on the different implementation levels (component, unit and application) will finally lead to directions for improved components, units and control strategies including guidelines, as well as training and inputs to future standards. The aim is to gather the knowledge and expertise of the participants on the different levels in order to forward this knowledge and establish recommendations and advices.

All presentations given at the workshop in the framework of the ICR2019  by Annex 51 members are now online and ready for download:


Annex 51 Acoustic Signatures of Heat Pumps in the framework of the International Energy Agency Technology Collaboration Programme on Heat Pumping Technologies

Acoustic Regulations of Heat Pumps

1D Modelling of Heat Pumps including Acoustics

Simultaneous energy efficiency and acoustic evaluation of heat pump systems using dynamic simulation models

Acoustic Emissions and Noise Abatement of Air to Water Heat Pumps – part1

Acoustic Emissions and Noise Abatement of Air to Water Heat Pumps – part2

Testing campaign on the energetical and acoustical behaviour – part1

Testing campaign on the energetical and acoustical behaviour – part2

Heat pump noise – Operation dependence and seasonal averaging


Task 1 covers legislation, standards & regulations. Version 1 of the related documents is available for download. When IEA HPT Annex 51 finalizes, an updated version will be available here.





Final report of the national Austrian Project “SilentAirHP” (in german language)

English Version will be available soon!