Low carbon emission renovation of historical residential buildings

The urgency of renovating residential buildings in heritage conservation areas while addressing carbon emission reduction and energy performance has become a concern in the context of climate change. European directives stress the importance of enhancing existing buildings to achieve climate neutrality by 2050. An approximately 100-year-old wooden apartment building in the heritage conservation area in Võru, Estonia, was designed as a nearly zero-energy building (nZEB). This study examined the impact of different renovation scenarios, considering both embodied and operational carbon emissions. During the study, the technical requirements of the National Heritage Board were developed in several aspects. The results of this study indicate that it is possible to renovate buildings in heritage conservation areas and achieve great energy performance. In addition to improving energy performance, it is possible to make the restoration of a significantly damaged exterior with intermediate repairs more cost-effective for the owner. Deep renovation of a historical wooden building decreases its carbon footprint as it leads to more energy-efficient renovation solutions. This is because operational emissions dominate over embodied emissions in a cold climate. From an environmental perspective, it is more feasible to renovate historically valuable buildings more deeply than it is to upgrade the external appearance of buildings. Renovation work to achieve an nZEB building should include insulating the thermal envelope while restoring the historical appearance and preserving the original building profile. In conclusion, this study offers a comprehensive analysis of various scenarios, including carbon footprint, energy performance, and cost optimality, related to different renovation strategies for buildings located in heritage conservation areas. There is a need to align heritage board technical requirements with the environmental perspective. Given that major renovation is more cost-effective and better at preserving the exterior appearance compared to staged renovation, the former should be preferred to ensure the owner's willingness to pay.