ecbcs building


Annex 50 Prefabricated Systems for Low Energy Renovation of Residential Buildings

Status: Completed (2006-2011)

Operating Agent: Mr Mark Zimmermann, EMPA-ZEN, Überlandstrasse 129, CH 8600 Dübendorf, SWITZERLAND

Tel: +41 (0) 44 823 4118
Fax: +41 (0) 44 823 4009



Energy conservation is largely dominated by existing buildings. In most industrialized countries new buildings will only contribute 10% - 20 % additional energy consumption by 2050 whereas more than 80% will be influenced by the existing building stock. If building renovation continues at the current rate and with the present common policy, between one to over four centuries will be necessary to improve the building stock to the energy level of current new construction.

Currently, most present building renovations address isolated building components, such as roofs, façades or heating systems. This often results in inefficient and in the end expensive solutions, without an appropriate long term energy reduction. Optimal results can not be achieved by single renovation measures and new problems could arise, including local condensation or overheating.

The objectives are the development and demonstration of an innovative whole building renovation concept for typical apartment buildings based on:
  • Prototype, prefabricated roof systems with integrated HVAC, hot water and solar systems,
  • Highly insulated envelopes with integrated new distribution systems for heating, cooling and ventilation.
The advantages of these prototypes include:
  • Achieving energy efficiency and comfort for existing apartment buildings comparable to new advanced low energy buildings;
  • Optimised constructions and quality and cost efficiency due to prefabrication;
  • Opportunity to create attractive new living space in the prefabricated attic space and by in-corporating existing balconies into the living space;
  • A quick renewal process with minimised disturbances for the inhabitants.
The project has been structured according to the following five research areas:

  • Concept definition and specification;
  • Integrated roof systems;
  • HVAC and solar systems;
  • Façade elements;
  • Monitoring and dissemination.

Participating Countries: Austria, Belgium, Czech Republic, France, Netherlands, Portugal, Switzerland


Publications Annex 50

Project Summary Report
Mark Zimmermann
2012, AECOM Ltd, United Kingdom

Building Renovation Guide
A building renovation guide documenting typical solutions for whole building renovations, including prefabricated roofs with integrated HVAC components and for advanced facade renovation. The idea is to develop an electronic tool, a type of 'Retrofit advisor' that allows an internet-based evaluation of suitable renovation strategies.

Guidelines for System Evaluation
Guidelines for system evaluation, design, construction process and quality assurance for prefabricated whole building renovation concepts. This publication includes the technical documentation of all developed renovation modules.

Documented Case Studies
Case studies of renovated demonstration buildings.

Project Summary Report
A synthesis report for a broad audience, demonstrating the potential of prefabricated retrofit.