Energy consumption in buildings is considered one of the main sources of energy consumption in the world and has a significant share in increasing carbon dioxide emissions into the atmosphere. In this context, optimizing building design to reduce energy costs and improve heating and cooling efficiency has gained special importance. Windows are recognized as one of the weakest components in terms of performance and energy efficiency in buildings, and adjusting the window-to-wall ratio (WWR) and the orientation of windows can have a major impact on energy consumption and the internal thermal conditions of buildings. The main goal of this research is to introduce and examine the optimal WWR to reduce cooling and heating loads in buildings under different climatic conditions based on conducted research. According to various studies, optimal WWR ratios depend on climatic conditions and local characteristics. These ratios are recommended according to different climatic conditions. Studies have shown that an appropriate WWR not only reduces energy consumption but also can have a positive impact on the performance of employees in office environments. Windows, by providing daylight and views to the outside environment, enhance the psychological and physiological satisfaction of employees, which ultimately leads to improved work productivity. It is recommended that the maximum WWR size in hot and dry areas should not exceed 30% for northern orientations and 25% for eastern and southern orientations. This reduction in northern orientations should be particularly noted to avoid increased cooling loads. In high-altitude areas like Abha, using a larger WWR (40%) improves thermal performance in winter. This setting with 40% WWR does not create any significant cooling load in summer. This study helps engineers, architects, and policymakers use the results to improve building design and standards.
