https://www.mdu.se/

The construction and real estate sector has a significant impact on the climate which increases the need for sustainable renovation and the reuse of building materials. The purpose of this study was to compare the climate impact of newly produced, reused and existing doors and windows, and to examine the factors influencing material selection in the renovation project S-huset. The study was conducted as a case study in collaboration with NCC and Hemsö. The method included Life Cycle Assessment (LCA) of life cycle modules A1–A5, document studies, literature study, a sensitivity analysis and semi-structured interviews with representatives from the client, contractor, architect and academia. The results showed that reused and existing building components generally had lower climate impact than newly produced alternatives. The greatest climate savings were achieved for doors, while the differences between the window alternatives were smaller due to technical requirements and the need to replace certain components. And for all analyzed alternatives, the production stage (A1–A3) accounted for the largest share of the total climate impact, showing the importance of material production in the overall results. It was also showed that material selection was influenced by climate calculations, the requirements of Miljöbyggnad Gold 4.0, material availability, technical requirements, economic conditions and project scheduling. Although reuse reduced climate impact, additional costs related to dismantling, storage, transport and refurbishment often limited its economic benefits. Reuse and preservation can substantially reduce the embodied climate impact of renovation projects. However a successful implementation depends on balancing environmental ambitions with technical, economic and practical project requirements.