Abstract—Life cycle assessment is a technique to assess the environmental aspects and potential impacts associated with a product, process, or service, by compiling an inventory of relevant energy and material inputs and environmental releases; evaluating the potential environmental impacts associated with identified inputs and releases; and interpreting the results to help you make a more informed decision. In this paper, the life cycle assessment of aluminum and beech wood as two commonly used materials in Egypt for window frames are heading, highlighting their benefits and weaknesses. Window frames of the two materials have been assessed on the basis of their production, energy consumption and environmental impacts. It has been found that the climate change of the windows made of aluminum and beech wood window, for a reference window (1.2m×1.2m), are 81.7 mPt and -52.5 mPt impacts respectively. Among the most important results are: fossil fuel consumption, potential contributions to the green building effect and quantities of solid waste tend to be minor for wood products compared to aluminum products; incineration of wood products can cause higher impacts of acidification and eutrophication than aluminum, whereas thermal energy can be recovered. Keywords—Aluminum window, beech wood window, green building, life cycle assessment, life cycle analysis, SimaPro software, window frame. I. INTRODUCTION HE concept of green building objects is to improve the environmental performance in all aspects of buildings. As buildings are a composition of numerous materials and subassemblies, tools have been developed to better inform environmentally preferable decisions [1]. Windows play a significant role in buildings, it accounts for 10-25% [2] of a building's exposed surface and available in a wide range of designs and frame materials. The primary contribution of windows to buildings is to incorporate daylight and to maintain the interior environment at desirable comfort conditions. An important aspect of windows is their environmental impact – energy consumption, natural resources depletion and environmental burden associated with their manufacture [3]. Ghada ElShafei is with the Department of Environmental Engineering, Egypt-Japan University of Science and Technology E-JUST, New Borg El- Arab, Alexandria, Egypt, (corresponding author, phone: +20-1116683799; E- mail: Ghada.Elshafei@ejust.edu.eg). Abdelazim Negm is with the Department of Environmental Engineering, Egypt-Japan University of Science and Technology E-JUST, New Borg El- Arab, Alexandria, Egypt (e-mail: negm@ejust.edu.eg). Selecting the most appropriate materials for any application depends on the consideration of a range of technical and economic factors including, for example, functionality, durability and cost. A further and increasingly important factor for material specifiers, in a world where sustainable development is a key issue, is the associated environmental performance of material applications from the perspective of manufacturing and product performance [4]. Among the tools available to evaluate environmental performance, life cycle assessment (LCA) provides a holistic approach to evaluate environmental performance by considering the potential impacts from all stages of manufacture, product use and end- of-life stages. This is referred to as the cradle-to-grave approach [5]. Salazar J. [1] applied the life cycle assessment on three window types commonly available in North America: PVC, fiberglass, and wood covered with an aluminum cladding. The LCA was based on the production of the three windows by a single representative manufacturer of each type. The damage modeling results indicated that the life cycle impacts are dominated by the combustion of non-renewable energy resources. Burning fuels cause increased emissions of respiratory inorganics, terrestrial acidification/nitrification impacts, and global warming. The PVC window's life cycle used the most nonrenewable energy and caused the most damage due to that window's shorter service life, 18 years vs. 25 years for fiberglass and aluminum clad wood. The use of cladding materials other than aluminum also prevented the disposal of aluminum into municipal landfills which reduced the aquatic Eco toxicity of the wood window's life cycle. Other potential improvements to the impacts of the three windows' life cycles include improving energy efficiency, particularly during secondary manufacturing. Asif M. et al. [3] addressed the life cycle assessment of the materials used for window frames of aluminum, PVC and timber window for a reference window (1.2m×1.2m). They concluded that Aluminum frames cause the highest burden to the environment because of the dangerous pollutants release and high energy consumption during aluminum production. PVC contributes large amounts of poisonous pollutants throughout its life cycle while timber window frames have the least environmental burdens. All frame materials deteriorate to various degrees by environmental impacts. PVC is sensitive towards heat and UV radiation. Timber if not frequently treated, can easily be affected by the environment. Aluminum, Life Cycle Assessment as a Decision Making for Window Performance Comparison in Green Building Design Ghada Elshafei, Abdelazim Negm T World Academy of Science, Engineering and Technology International Journal of Architectural and Environmental Engineering Vol:9, No:9, 2015 1155 International Scholarly and Scientific Research & Innovation 9(9) 2015 ISNI:0000000091950263 Open Science Index, Architectural and Environmental Engineering Vol:9, No:9, 2015 publications.waset.org/10002174/pdf