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Deliverables from the Annex

The main deliverables of three years of international collaboration are:
Technical Reports
Example Projects
R&D Overview
Scientific Publications

Heat Pump Water Heaters

The production of hot water will become the dominant factor in building heating systems, with heat pumping technology as one of the most efficient generating technologies.

HPT Annex 46

The production of domestic hot water is becoming the dominant factor in heating systems for new buildings as well as for the renovation of existing buildings.

The conclusions of the work done under the Annex can be found in the Final Report in which topics are highlighted such as:


The Annex 46 project has been undertaken under the TCP on Heat Pumping Technologies with support from experts under the IIR.

R&D and Future Work

The Annex formally ended September 2019 with a successful Workshop at the ICR 2019 in Montréal. However the message from the Annex is still important.

There is still a lot of work to be done which showed at the recent 13th IEA Heat Pump Conference with a number of R&D projects worldwide.

Next to his necessary sometimes fundamental R&D work, a focus on boundary conditions in the various markets as well as stronger policy support is needed to get a wider acceptance of the heat pumping technologies for domestic hot water.

“… the share of hot water production in the overall heat consumption of the building has increased in new single family as well as multifamily buildings, but also in deep renovation projects…”

Onno Kleefkens MSc
Project manager