About Annex 61

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.


  • To provide a framework along with selected tools and guidelines to significantly reduce energy use (by more than 50%) in public buildings undergoing major renovation
  • To gather and, in some cases, research, develop, and demonstrate innovative and highly effective bundled packages of Energy Conservation Measures for selected building types and climatic conditions
  • To develop and demonstrate innovative, highly resource-efficient business models for retrofitting buildings using appropriate combinations of public and private funding


This effort focuses on deep energy retrofits of government/public buildings with low internal loads: office/administrative buildings, dormitories/barracks, public housing, and educational buildings.


  • Buildings owners: executive decision makers and energy managers of public, governmental, and military administrations
  • Private capital financiers considering investment in building energy efficiency such as Energy Service Companies (ESCOs), utility companies, and energy efficiency funds
  • Technical experts: ESCOs and general contractors; design, architectural, and engineer firms, and manufacturers of energy efficient products and systems

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