SUREFIT- Sustainable solutions for affordable retrofitting of domestic buildings

To reduce greenhouse gas emissions caused by buildings, the EU has declared the Renovation Wave strategy with the goal of retrofitting existing buildings to be more energy efficient. Long-term emission reductions require both speedy and cost-efficient renovation methods. The Surefit project aims to develop practical means for effective building retrofitting. The aim is to reduce emissions and CO2 emissions by 60%, to reduce installation time by 40% and to demonstrate a payback period of less than 10 years. New modular technologies for improving energy efficiency and indoor conditions will be tested. This study examines three demonstration buildings chosen from three European countries (United Kingdom, Spain and Greece). Each demonstration building was modelled using IDA-ICE and their energy demands simulated to provide the baseline for energy efficiency. Then, various retrofit options were tested using dynamic computer simulations, with the aim of finding out the impact of the different technologies in different climates and under different energy mixes. This study focuses on measures integrated to the building envelope and structure, namely bio-based thermal insulation, solar electric low-energy windows and phase-change materials. Thermal insulation of the building envelope using bio-aerogel reduced CO2 emissions by 41-43% in continuously heated buildings, but only by 15% in an intermittently heated building. The emission impact of PV glazing was only 3-8%. PV glazing resulted in a slight reduction of overheating in Spain and UK, but increased the temperatures in Greece, because it could not replace the external shading device that was removed when PV glazing was installed. The benefits of PCM were low. A smart ventilation control scheme or a different type of PCM material could help in attaining additional benefits.