The Egyptian Residential Energy Code (EREC) provides specifications and recommendations for the construction of buildings that aim to provide comfort built environment for the occupants. Among these specifications are many dependency relationships between different variables that affect the selection process of the building fenestration. The effect of these variables (window-wall ratio and glass thermal properties) and their associated shading devices (recommended by EREC) on the optimization of energy consumption, as well as its long-term cost-effectiveness, is the main focus of this paper, investigated in three climatic zones in Egypt, under different climate change scenarios. Although these specifications are well-defined in EREC, recommendations of the best combinations of these variables (for each climatic zone) do not exist. The findings recommend different combinations of window wall ratios, glass types and associated shading devices according to each climatic zone, to achieve indoor thermal comfort, as well as long-term cost-effectiveness. (C) 2013 Elsevier B.V. All rights reserved.