IEA EBC - Annex 61 - Business and Technical Concepts for Deep Energy Retrofits of Public Buildings

Annex 61 Definition of Deep Energy Retrofit (DER): Deep Energy Retrofit is a major building renovation project in which site energy use intensity, including plug loads, has been reduced by at least 50% from the pre-renovation baseline.


It is now becoming more common in many industrialized countries to impose stringent targets for reductions in energy use in government/public buildings. However, the funding and “know-how” (applied knowledge) available for owner-directed energy retrofit projects has not kept pace with new requirements to increase the number of energy retrofits and to improve the energy efficiency of existing buildings.

When different technologies are implemented (“bundled”) together, they can result in significant energy use reductions, require smaller investments, and consequently have faster paybacks. Numerous case studies show that deep energy retrofit is possible and cost effective when it is combined with a major building renovation project. Such projects can be funded using either public or private sector funding, alone or in combination.

Annex Info & Contact

Status: Completed (2012 - 2017)

Operating Agents

Rüdiger Lohse
KEA Klimaschutz- und Energieagentur
Baden-Württemberg GmbH
Kaiserstr. 94a
76133 Karlsruhe
Tel: +49 (0)721 984 71 15

Dr Alexander Zhivov
US Army Engineer Research and Development Center Construction Engineering Research Laboratory
2902 Newmark Dr.
Champaign, IL 61826-9005
Tel: +1 217 373 4519

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