AP 6: IEA-HPP-Annex 50 „Heat Pumps in Multi-Family Buildings“

Up to now heat pumps have not established on the multi-family building sector, although there is a high potential for their application, especially in combination with the renovation programme of existing buildings. Barriers exist on the user´s side in a lack of information and experience with the technical possibilities that heat pumps offer in multi-family houses, in the economic evaluation of the technology options as well as in the still needed technical development of heat pump appliances and systems for multi-family buildings.

The planned annex should analyse these barriers at the international level and collect and further develop solution proposals to overcome them. The annex offers the possibility, in collaboration with the companies involved in the thematic project network LowEx-Bestand, to bring users (building companies) and the scientific environment together on an international level and to enable a constant mutual exchange making the results of the analysis available to a larger circle of relevant stakeholders.

Objectives and focus areas

  • Increased use of heat pumps in the field of multi-family buildings and consideration of compression heat pumps and gas heat pumps to this purpose
  • Development of concepts for the use of heat pumps in energetically renovated and non-renovated multi-family buildings
  • Optimisation of system-engineering concepts: definition of optimal sources and source combinations, operations management and system-oriented approaches for integration with possibly existing facilities for different building types and analysis of environmental and economic conditions
  • Collection and analysis of application data though demonstration and monitoring of market-oriented heat pump developments in multi-family houses
  • Dealing with the questions in close co-operation with the industry and users (building companies)

Technological questions

  • Further development of electric and thermally driven heat pumps, heat pump components and heat pump systems for the use in multi-family houses
  • Heat distribution and transfer system: use of existing systems vs. installation of new systems
  • Centralised vs decentralised hot water production (link with Annex 46)
  • Optimisation of the bivalence point or hybrid heating systems (link with annex 45)
  • Connection of the heat pump with the existing heat supply
  • Optimal location of the heat pump (minimising noise emissions and distribution losses)
  • Combination of the heat pump with a ventilation unit (source or sink side)


  • Market overview, system and building classification in international comparisons
  • Database of existing products and solutions
  • Simulation results for different systems and operating conditions (climates in international comparisons, i.e. also outside Germany)
  • Overview of new components and system developments
  • Best practice examples as references for the implementation of heat pumps in multi-family houses
  • Website, final report

Contact person

Dr. Marek Miara
Fraunhofer ISE
Heidenhofstr. 2
79110 Freiburg
+49 761 4588-5529

More detailed information on IEA-HPP-Annex 50 „Heat Pumps in Multi-Family Buildings“.