High performance glass such as low-e coated or heat reflective glass offers better thermal performance, preventing undesired heat loss or gain during a building operation phase. However, these coatings may not be as effective in certain climate zones and create glare problems for adjacent buildings. A transparent composite facade system (TCFS) was newly configured to provide a sustainable alternative to a high performance glass wall in that the biofiber composite core acts as a shading device while the airspace between the polymer skins provides adequate insulation. A comparative life cycle assessment (LCA) method was selected as a sustainability measuring tool to compare the environmental impacts of a TCFS with a glass curtain wall system (GCWS). In this paper, the environmental performance of a facade system is characterized by the energy consumption and CO2 emissions through all stages of the life cycle. Comparative LCA results show that the total life cycle energy of the TCFS is estimated to be 93% of that of the uncoated GONS, and the total emissions of kg CO2 equivalent for the TCFS is determined to be 89% of the uncoated GCWS. The use phase for both the TCFS and GCWS plays a dominant role in reducing environmental impacts while the impact associated with transportation and the end-of-life management is estimated to be insignificant in this study. The life cycle inventory data and analysis results provided in this paper are expected to assist designers with a better understanding of building material selection and system improvement from the whole life cycle perspectives. (C) 2011 Elsevier B.V. All rights reserved.