Estimation of sound propagation using a web-based 2D-tool

63

Motivation

  • Noise emissions from heat pumps are a key barrier for wide implementation
  • Especially in urban living areas sounds limits might restrict installation

Current challenges:

  • Detailed models are complex and not practical for quick decision-making
  • Simplified approaches often neglect geometry, surroundings, and barriers

Objectives of the 2D-Tool:

  • Provide an easily accessible (“for everybody”) estimation of sound propagation (based on ISO 9613)
  • Consideration of Distance:
    • Installation configuration (e.g., ground, wall)
    • Barriers and shielding effects
    • Support planning, positioning, and scenario analysis

Approach

  • Implementation based on a previous web-based interactive 2D-tool from Danish Technological Institute
  • Sound propagation based on ISO9613-2 for a hemispherical propagation
  • Considered attenuations:
    • Sound shielding: Reduction of direct sound due to insulatio
    • Reflection & amplification by nearby structures: Increased sound levels caused by building façades and confined geometrie
    • Directional radiation of the outdoor unit: Non-uniform emission depending on fan orientation and housing design
    • Ground effect (surface characteristics): Differentiation between acoustically hard (e.g. concrete) and soft (e.g. grass) surfaces influencing absorptionDiffraction at barriers: Sound propagation around obstacles (e.g. walls) when no direct line of sight exists
  • Vizualization of sound propagation

Implementation

  • Freely accessible web-based tool
  • Use of geospatial data (OpenStreetMap) for realistic environments
  • User interface in at least 4 languages (IT, FR, DE, EN)

Access the 2D-Tool!

  • Web application available from May 20, 2026
  • Live presentation of the tool at the IEA Heat Pump Conference 2026 in Vienna!

DISCLAIMER

This free online tool provided by IEA HPT Annex 63 is intended solely for scientific and demonstration purposes. It provides a non-binding estimate of heat pump sound levels based on simplified models and user-provided input data. Actual sound levels may vary significantly. The online tool does not replace professional planning, measurement, or official assessment. Verification by qualified experts is expressly recommended. The online tool is provided “as is”. TU Graz makes no warranties, whether expressed or implied, including, but not limited to, any implied warranties of fitness of the online tool for a particular purpose.  TU Graz is not liable for any errors of the online tool and does not warrant or guarantee a specific utility of the online tool. The risk as to the quality, functionalism and performance of the online tool is with the user. In particular, TU Graz is not liable for direct or indirect damages or subsequent damages due to errors of the online tool.