Science and Education Publishing American Journal of Civil Engineering and Architecture 2328-3998 1 1 2013 11 03 A Comparative Study on Green Wall Systems 143 155 EN Arash Zia Department of Architecture, University of Tehran, Tehran, Iran Kaveh Zia Airya Norouzi Larki AJCEA2013164 10.12691/ajcea-1-6-4 2013 10 11 2013 10 17 2013 11 03 Greening the building envelope focusing on green facades with vegetation is a good example of a new construction practice. Plants and partly growing materials in case of green wall systems (GWS) have a number of functions that are benefificial, for example: increasing the biodiversity and ecological value, mitigation of urban heat island effect, outdoor and indoor comfort, insulating properties, improve of air quality and of the social and psychological well-being of city dwellers. This paper discusses a comparative life cycle analysis (LCA) for: a conventional built up brick facade, a facade greened directly, a facade greened indirectly (supported by a steel mesh), a facade covered with a green wall system based on planter boxes and a facade covered with a green wall system based on felt layers. Beside the environmental bene?ts of the above described greening systems, it is eventually not clear if these systems are sustainable, due to the materials used, maintenance, nutrients and water needed. A LCA is used to analyze the similarity and differences in the environmental impacts in relation with bene?ts estimated for two climate types for building energy saving (reduction of electrical energy used for building cooling and heating).