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

Target of IEA EBC Annex 61 was the development of technical and economical concepts for Deep Energy Retrofit of public buildings. To force high-quality and energy efficient retrofit, besides the enhancement and dissemination of innovative, technical retrofit concepts, the focus was in the development of innovative business models (energy-contracting).

Short Description

In the building sector major potentials to reach climate and energetic goals can be found in energy efficient retrofit of existing buildings. As buildings have very long retrofit cycles (30 – 50 years) Deep Energy Retrofit is very important. So each unambitious retrofit is a vain chance to realize maximal potentials to reach climate and environmental targets. Public authorities are aware of this impact forcing stronger goals both on legal and subsidy level. Furthermore public authorities are aware of their role as frontrunner, realizing "Lighthouse retrofits" (renovation to Low Energy and Passive House standard) within their own building stock. However it turns out, that these projects are exceptions to the rule and high quality retrofit with large potential for energy reduction is not state of the art in the public building sector. Within the framework of Annex 63, besides innovative technical packages of measures for Deep Energy Retrofit of public buildings, strategies and tools for innovative energy contracting methods as well as the provision of results for important stakeholder in the retrofit area was worked out. The working plan consist of following subtasks:

  • Subtask A: Bundles of Technologies
  • Subtask B: Business Models for Market Implementation
  • Subtask C: Demonstrate Selected Deep Energy Retrofit Concepts
  • Subtask D: Develop an IT-Tool for Decision Makers and ESCOs

Based on case studies in different climate zones (based on real retrofit projects in participating countries) technical and economical optimized measures for Deep Energy Retrofit have been analyzed to derive recommendations for stakeholders.

Based on the know-how and on experiences of the participants in Annex 61 different instruments and tools have been developed (download under

Results and conclusions

Based on project results following recommendations for future, energetic retrofits can be derived:

  • Promotion of integrated planning processes – Integration of all relevant disciplines in the whole planning process.
  • Life Cycle Costs perspective enables easier realisation of Deep Energy Retrofits.
  • Early involvement of occupants has strong influence on energy reductions.
  • Forcing monetary assessment of co-benefits (comfort, health, etc.), as they are definitely bankable.
  • Quality assurance is an important factor to reach planed targets.
  • Forcing of integrated energy-contracting – Higher volume of orders (potentially more technical measures for a building) increases the economic feasibility.

Most important publications of IEA EBC Annex 61, presenting project findings for the requirements of different target groups are:

  • Deep Energy Retrofit Business Guide. Annex 61 Subtask B report
  • Deep Energy Retrofit Guide for Decision Makers. Annex 61 Subtask D report


Austria, Belgium (observer), China (observer), Denmark, Estonia (observer), Finland, Germany, Ireland (observer), Lativia (observer), Netherlands (observer), UK, USA

Contact Address

AEE – Institute for Sustainable Technologies (AEE INTEC)
DI Heimo Staller, DI Dr. Anna Maria Fulterer
Feldgasse 19, A - 8200 Gleisdorf