The building roof is one of the most important components of the building's envelope, as it plays a major role in protecting the internal spaces from the harsh climatic conditions of the external environment, as reaching thermal comfort in inner spaces is an essential issue required by its users. Thus, the research aims in enhancing the performance of vaulted roofs as they are known by their increasing heat gain leading to the rise in temperature of the inner spaces, eventually the loss of thermal comfort in which this research seeks. Hence, this study is an attempt to evaluate and test the thermal performance of such residential buildings located in the Egyptian dry desert climate. In achieving so, the research adopts an analytical field approach by measuring both internal and external temperatures and humidity of a single vaulted residential room in Heissa Island of Aswan city in southern Egypt, as a representative case study of the dry desert climate. Two main devices are therefore utilized for measuring both the internal and external temperatures, noting that the wind factor is neglected as any openings have been entirely shut, The results showed that the temperature is far from the comfort zone, which leads to the consumption of more energy to reach the room's atmosphere to feel the thermal comfort inside.