Interpreting environmental impacts of wooden windows based on existing EPDs: An application in Italy

Abstract

To meet climate targets, it is necessary to adopt robust and recognized methods, such as life cycle assessment (LCA), to evaluate emissions, particularly from building materials. As shown in the literature, embodied impacts have become as significant as operational impacts. The embodied impacts of a specific product are given in a transparent and quantitative manner in environmental product declarations (EPDs), based on LCA results. Windows play a crucial role in the energy performance of buildings. In fact, they typically account for 10–25 % of the exposed area of a building, resulting in more than 60 % of its total energy loss. In Italy, wooden windows make up 28 % of the window market and are the cheapest option for mild climates over a timeline of 60 years. However, an important element is still missing: a simplified interpretation of EPD results to enable straightforward, balanced comparisons of the environmental performance between alternatives. In this context, an analysis based EPDs of wooden windows is proposed, with a focus on production and use stages, for the six Italian climate zones. The three main steps of the study are: 1) evaluation of the influence of window properties on the embedded impacts; 2) assessment of maintenance scenarios; and 3) estimation of operational impacts regarding window properties and exposed climate. The results suggest that the influence of thermal transmittance, wood type and exposed climate is higher for cold climates due to better performing production materials and more frequent maintenance during service life.