Window Maintenance Versus Replacement: A Comparative Life Cycle Analysis from Subarctic Sweden

Previous building renovation studies have evaluated the life cycle (LC) impact of replacement to new, more energy-efficient windows, comparing it to optional renovation measures and base scenarios. However, periodic maintenance to avoid replacing existing windows has attracted less attention in research and practice, especially in subarctic climates with high heating demands by buildings. The objective here is to assess the LC impact of various scenarios of maintenance and replacement of different window types on a 1980s multi-residential building in subarctic Sweden. The scenarios were compared based on estimated climate impact and costs during product and operational stages. A reference study period (RSP) of 60 years was chosen. Results show periodic maintenance of existing windows to be the preferable option regarding LC climate impact and costs. In the replacement scenarios, the reduced heating energy use affected the climate impact more than the costs. The scenarios showed varied sensitivity to changes in RSP, intervention rate and discount rate, increasing the uncertainty of the assessment. The results highlight maintenance is worth considering among property owners when deciding on renovation measures, but also in future research studies.