Iwan, also Eyvan, is strongly associated with the architecture of the Middle East. It has been widely used as a space to serve different purposes in various types of traditional buildings such as mosques, palaces, and houses. This study focuses on the environmental aspects of iwan . The research investigates the effects of changing the exposure degrees of iwan on its insolation within traditional houses in Sulaymaniyah’s old town. Both EnergyPlus and Google SketchUp programs were used to make a 3D model and perform energy simulation analysing for a typical building with iwan in different proportions, similar to what exists in the region. Furthermore, weather data of Sulaymaniyah (latitude 36°) is used in the simulation process. Several main geometrical variables are affecting the exposure degrees of iwan in Sulaymaniyah: Firstly, the length and depth of the space change in different houses whereas the height is almost constant, the same as the building’s height, which equals to 3m. Secondly, the orientation of the iwan , which is usually facing southeast, south, southwest, and both east and west, considered in the simulations and the results obtained separately for each orientation. There is no doubt that in hot seasons, shading is preferable. Whereas, in cold seasons, receiving more solar irradiation is desirable. Based on the results, iwan’s solar performance improves whenever its width is decreased compared to its depth. In addition, the results show that the iwan’s orientation affects significantly on its solar performance, as those facing towards south have better performance, meanwhile, those facing north have it the worst. Furthermore, changing the depth to width ratio for those facing east and west does not seem to affect their solar performance noticeably. Moreover, the results examine to what extend iwan can be used in buildings as a climatic responsive design strategy in Sulaymaniyah.