Whole-life emissions of retrofitting a pre-1919 house in Scotland: a whole-building approach

Introduction: In recent years, the impacts of climate change have become more pronounced, necessitating a net-zero economy to mitigate them. Scotland has an ambitious plan to reach a zero-emission economy by 2045. To achieve this plan, significant work is required in all economic sectors, including the built environment, to reduce emissions. Existing buildings are a major contributor to climate change; therefore, sustainable, low-emission plans should be used in their retrofitting. Materials and methods: This study presents a reproducible paradigm for whole-building retrofit assessment that integrates life-cycle assessment with building performance simulation. This plan consists of measuring the house’s baseline impact, proposing fabric and heating system upgrades, and integrating renewable energy. The embodied carbon of each material was calculated to assess the total life-cycle impact of the interventions. After that, we compared the retrofit plan with the baseline energy performance and carbon emissions. Results: This study demonstrated the impact of implementing a whole-building retrofit package. Upgrading the case study fabric and integrating Heat Pump (HP) had a significant impact, reducing energy demand and emissions by more than 50% each, with a reasonable carbon payback period of less than a year for both. Upgrading the heating system to a high-efficiency model reduced energy demand and emissions by around 10%. Integrating a photovoltaics (PV) system into the selected case study met about 10% of the house’s energy demand but had a long carbon payback period. Conclusions: The results of this research show that implementing low-embodied-carbon retrofit materials can achieve substantial reductions in carbon emissions and energy consumption while maintaining low embodied carbon.