European initiatives towards improving the energy efficiency in existing and historic buildings

Increasing the building sector's energy efficiency while reducing CO2 emissions, constitute the main challenge that most European cities need to tackle. In Europe the building sector is responsible for nearly 40% of the total energy consumption. Considering the slow rates of constructing new buildings, a lot of attention needs to be paid to the already existing building stock. This paper presents some of the major projects carried out in Europe and their achievements regarding the integration of innovative technologies and use of different sources of renewable energy in existing buildings. Special attention has been paid to projects targeting historic buildings, since their significant cultural and historic values make their refurbishment and retrofitting process more complex. (C) 2015 Authors. The Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license