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.

With the increasing interest in energy-efficient building design, building energy simulation programs are increasingly employed in the design process to help architects and engineers decide which design alternatives save energy more. This research is an empirical and analytical study using a ready-made software package to evaluate the energy efficiency performance of building envelopes using recycled waste material. These methods used available environmental alternatives material in the experiment. To verify the results, two practical cases are tested. Validation is examined by comparing experimentally measured data and computational simulation data during the same summer period time. Real cases with small-scale actual rooms that were used to generate data to validate numerical models. The focus of this study is to compare the experimental measured thermal behavior of traditional and waste materials in residential buildings with simulation results. This comparison allows determining the effect of using waste material in southern walls of a residential building at an indoor temperature during hot summer days, in which the measurements took place during June and July. Meanwhile, the results indicated that the indoor temperature of real models was higher than the temperature of simulation models with about 3°C to 6 °C at measuring time (six summer days). This increase is about o 5.4% to 11.8%. The findings also revealed that the use of waste material in the southern wall of a residential building could decrease the indoor temperature by about 0.2 - 3°C degree compared with the traditional material at the same wall. It means that waste materials in southern walls could decrease 0.9% to 4.1% of indoor temperature compared with traditional materials. This study found that the analytical and empirical small-scale models could contribute to determining the usage of waste material at southern walls of residential buildings. Also, the comparison of the results indicates that Design-Builder can predict indoor temperature to achieve thermal comfort with good accuracy and it can be used by researchers and designers to evaluate the thermal performance of buildings.