A new retrofitting strategy for the improvement of indoor environment quality and energy efficiency in residential buildings in temperate climate using prefabricated elements

The renovation of existing residential buildings across Europe has become a key factor for energy saving and the improvement of Indoor Environment Quality (IEQ). This paper presents an investigation of IEQ for a typical 1960s single-family house in Germany before and after a new retrofitting strategy (prefabricated element with integrated ventilation and new thermal envelope). In-situ measurements were applied to investigate the energy efficiency and IEQ improvement for the new retrofitting strategy in temperate winter regions of Europe. The simulation model replicates the measured data to be closer to reality and simulates a home office (COVID-19) scenario. The in-situ measurements showed that our retrofitting strategy increases the indoor air temperature during the heating period by up to 2.5 °C, decreases relative humidity by up to 3.8% and increases CO₂ by up to 24 ppm than before. As the simulation results shows, the retrofitted home office scenario allows a reduction in heating energy of up to 77%, an increase in CO₂ concentration of up to 41.8 ppm, 0.5% less relative humidity and 1.6 °C higher indoor air temperature than that without retrofitting. The new approach to retrofit residential buildings thus showed a potential in energy saving and improving the IEQ.