Life Cycle Perspectives of Fixed and Operable Wooden Windows

Windows represent a critical component of a building’s envelope, influencing not only thermal performance and natural interior lighting but also the overall environmental impact of the structure. This study applies life cycle assessment to evaluate the impacts of operable and fixed wood-based windows covering the system boundaries of the product stage and maintenance. Scenarios are modelled for different frame surface treatments, regarding varnish layers, paint presence, and aluminium cladding. The impact categories assessed include elements, fossils, and ozone layer depletion; potentials of global warming, acidification, eutrophication; photochemical ozone creation; and toxicity to humans, freshwater and marine water, as well as terrestrial ecotoxicity. The results indicate that the embodied environmental impact of the wood material alone remains relatively small while glazing and aluminium cladding dominate. Regarding the surface treatment, the varnish quantity as well as the presence of paint do not significantly influence the environmental impact. Differences between operable and fixed windows also reflect additional materials and hardware requirements, resulting in operable windows exhibiting higher environmental impacts across all assessed categories. The findings of this study highlight the important role of structural elements and additional components on the overall environmental impact regarding the complexity of a window.