A comparative life cycle study of window interventions: Impact of building characteristics and local context

Improving building envelope components, such as windows, is a common renovation measure in cold climates to increase energy-efficiency. However, the life cycle ( LC ) benefit of maintaining or replacing windows is highly uncertain and depends on the building, its context and methodological choices made in LC assessments. This study aimed to expand knowledge on how buildings’ characteristics and local context (location-related) influence the preferred window intervention option by investigating the LC climate impact and costs of various window maintenance and replacement scenarios for two typical residential buildings in subarctic Sweden. Using life cycle assessment and life cycle costing, along with sensitivity analyses of seven relevant parameters, the study explored the total climate impact and costs over a 60-year period for each window intervention’s production and operational stages. Results indicate that building characteristics are important, as the two buildings show contrary LC results, even within the same local context. Swapping the buildings’ location affects initial LC performance, and which sensitivity parameters appear critical. The parameters influence the LC results, but only a few alter the window interventions’ rankings, with heating emission factor having most impact. Reducing LC climate impact and costs by replacing windows is not guaranteed, as it depends on building characteristics and local context. Instead, window maintenance may be preferred for its lower material use. The study’s integrated LC approach provides insights for harmonizing renovation budgets with climate targets. Adapting renovation measures to each specific case is key for choosing the best option, balancing operational and embodied impacts. • LCA and LCC evaluation for window maintenance and replacement in cold climates. • Reduced heating demand from replacement does not always reduce life cycle impacts. • In cold climates, maintenance benefited buildings with decent thermal properties. • Remote transportation increased climate impact, yet the preferred option remained. • Low-carbon heating sources favored maintenance over replacement.