Sustainable domestic hot water production with heat pumping technologies will become the dominant energy demand in the domestic infra structure offering affordable smart storage opportunities.

Domestic sector energy consumption is mainly concentrated around space heating and hot water demand. Due to new building regulations and energy efficiency measures, in the future, space-heating demands will decrease, by inherently better insulation. But domestic hot water demand will remain relatively constant and can even increase as a consequence of higher comfort demands (e.g. rain-showers) by the end user. Thus due to strict legislation on energy performance domestic hot water is going to dominate the overall energy use in houses, both for the end use in kWh and in capacity.

The objective for the Annex is to analyse the information on hot water heat pumping technologies for the production of sanitary hot water in domestic and other applications. This information will be structured in such a way that leads to better understanding in the market by the end user and policy maker.

The work under the Annex will provide deeper insight into the potential of applying domestic hot water heat pumps using various concepts and systems for new as well as existing buildings by:

  • Reviewing available domestic hot water heat pumps and double function heat pumps making hot water next to space heating and/or cooling.
  • Reviewing the different systems for domestic hot water in their traditional and potential applications and gaining deeper insight in to the use of domestic hot water in order to create a solid basis for test and standardisation procedures.
  • Developing and validating models to enable an objective comparison of domestic hot water heat pumping technologies and other systems.
  • Making an overview of R&D, and sketching a scenario on the needed R&D. This information will be provided to industry players, institutes, and governments with the goal of achieving simple and low-cost solutions.
  • Data basing and where possible monitoring example projects to inform stakeholders of the viability of concepts.
  • Creating a web based information platform to serve countries participating in the Annex by publishing information on their market, legislation and policy.
  • Holding regular workshops
  • Collaborate with other related Annexes within the HPT-TCP or other TCP’s

Project manager and participating countries

Japan,  South Korea, United States, Canada, France, Switzerland and UK. Netherlands is Operating Agent.


The Annex has been structured into the following tasks:

  • Task 1. Market overview, barriers for application
  • Task 2. Systems and concepts in comparison to alternatives
  • Task 3. Modelling calculation and economic models
  • Task 4. R&D
  • Task 5. Example projects and monitoring
  • Task 6. Communication and training

Publication and result

The main objective is to provide deeper insight into the possibilities for implementation and potential reduction of CO2 emissions and energy costs using various domestic hot water heat pump concepts and systems for new as well as existing buildings. This will be achieved by delivering:

  • A scenario for future developments based upon a market analyses
  • A calculation model for the objective comparison of domestic hot water systems and concepts with heat pumps and/or other technologies;
  • Gaining deeper insight into the use of domestic hot water to create a solid basis for test and standardization procedures;
  • A roadmap on Research and Development based upon future market needs;
  • Showcasing existing and new concepts in practice and/or research and where possible supported by monitoring results;
  • Creating a web-based information platform to serve participating countries by publishing information on their market approach and training courses;

The final Annex report will be available for general publication by 2019.


  • A number of Example Projects have become available in various of categories. Also some nice videos.
  • Papers published by Annex participants and related can now be found under the PUBLICATIONS page.
  • The PRESENTATIONS from the Annex workshop in Tokyo are now available, focusing on R&D in a number of participating countries
  • 13th IEA Heat Pump Conference will be in 2020 in South Korea on Jeju Island. The Call for Abstracts is expected to be published soon.
  •  25th IIR Conference ICR 2019 will be held from 24th – 30th August 2019 at Palais de Congrès de Montréal. At the Conference a special workshop will be organized by the Annex 46 on Domestic Hot Water Heat Pumps. The focus will be on R&D and future developments.
  • The upcoming Working Meeting for participating countries will be held from 26th – 28th November in Buchs (Switzerland) on the invitation of NTB Interstaatliche Hochschule für Technik.

Field News

What happened before and since Rotterdam?

Some high lights Annex participants had 10 presentations at Rotterdam Conference A successful Workshop at Rotterdam Conference showed potential synergies...