The pace and scale of the global clean energy transition is not in line with climate targets. Energy-related carbon dioxide (CO2) emissions rose again in 2018 by 1.7%. The buildings sector represented 28% of those emissions. The growing global need for thermal comfort is a large contributor to emissions of greenhouse gases world-wide, and the transition to renewable energy is too slow.

Technology can reduce buildings emissions while improving comfort and energy services. Multiple cost-effective technologies unleash average energy savings of 500 Mtoe per year in the buildings sector worldwide between 2020 and 2050. To meet the needs of the future, new innovative thermal comfort solutions need to be developed. Heat pumps cut typical energy use for heating by four or more. Integrated systems consisting of heat pumps and storage are an important technological option in order to accelerate the use of renewable energy for heating and cooling. By combining heat pumps and storage, several issues are addressed, such as:

» Balancing & controlling electricity grid loads;
» Capturing a large (or larger) share of renewable (local/regional) power input (e.g., solar thermal, solar PV);
» Optimizing economics, CO2 emissions, total fuel use over time;
» Providing optimal supply security to buildings.


Annex 55 aims to accelerate market development of Climate and Comfort box solutions. The technical challenge is the smart combination of different technologies in one system. Specialists from various fields of technology are required, and need to cooperate in order to accelerate product development and market introduction of combined heat pump / storage packages: The Comfort and Climate Box (CCB). The goal is to develop nearly market ready systems, including, as a minimum, a heat pump and a storage system.

Publication & result

The Comfort and Climate Box will compile a portfolio of country-specific prototype testing and demonstration projects. A description of the market status will be elaborated. Derived from this, a roadmap will establish the next steps of development and describe how to implement the CCB in the respective markets, with recommendations for market participants and policy makers on how to enhance market uptake.

A Joint project

The Annex  is a joint project between the two Technology Collaboration Programmes (TCPs), Heat Pumping Technologies (HPT) and the Energy Storage (ECES), under the auspices of the International Energy Agency (IEA). The combined Annex will be ran in the ECES context under Annex number 34, and in the HPT envelop under Annex number 55.

Annex 55 invites new members to join Annex. Read more here.

Contact Person

Mr Peter Wagener,

Participating Countries

Austria, Belgium, Canada, China, Germany, Italy, the Netherlands, Sweden, Switzerland, Turkey (from ECES TCP), the UK, the USA