Prefabricated Systems for Low Energy Renovation of Residential Buildings: Building Renovation Case Studies (IEA ECBCS Annex 50)

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 incorporating 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 
Participants: Austria, Czech Republic, France, the Netherlands, Portugal, Sweden, Switzerland