Modernization of Windows and Doors in Protected Buildings: Possibilities and Their Environmental Impacts

During the renovation of protected buildings, strict regulations must be met. Buildings of different ages and protection categories require different structural solutions, including the modernization of windows and doors. In addition to heritage protection aspects, environmental awareness, sustainability, energy efficiency regulations, and the objectives of Fit for 55 and the Green Deal are given a prominent role. The research examines how the different categories of protection appear in Hungary in connection with the replacement of windows and doors and what regulations apply to their renovation. A case study of a historic building examines the effects of the interventions, with particular regard to the reduction of CO2 emissions, with the help of life cycle assessment (LCA) based on a BIM model, using machine and manual calculations. The results show that it is worth staying with the original solid wood material because changing the material – for example, to modern PVC or aluminum triple-layer windows – involves a greater environmental impact. The methodology of the analysis can be used as an analogy for the renovation of other similar buildings and can serve as a basis for issuing different tenders.