This thesis presents a comprehensive comparative life cycle assessment (LCA) of advanced alternatives to traditional ductwork for ventilation systems in Danish commercial buildings. The research focuses on evaluating the global warming potential (GWP) of three ductwork materials including tailor-made fabric, glass wool, and galvanized Steel. Two case buildings, Sofiendalskolen school and City Campus Aalborg, were selected for the study. The methodology employed in this research involved a multi-step approach to analyze and design the ventilation systems in the case buildings. Subsequently, to conduct the life cycle assessment (LCA) of the ventilation systems, the LCAbyg tool was employed. The tool considered various stages of the life cycle, including production (A1-A3), replacements, operational energy use (B4 and B6), and end-of-life stages (C3 Waste processing, C4 Disposal). The “cradle-to-grave” approach was applied to assess the environmental impacts of the ventilation system and its components throughout their entire life cycle. The findings indicate that the choice of ductwork material significantly influences the environmental performance of ventilation systems. Fabric ductwork demonstrates a advantage over steel-based ductwork, showing lower CO2 emissions and a smaller environmental footprint. Glass wool ductwork, however, leads to higher CO2 emissions due to the need for frequent replacements. These findings have important implications for decision-making regarding ductwork material selection in commercial buildings, promoting sustainable practices and reducing environmental impact