Algeria is a country that has witnessed rapid development as a result of its abundant oil supplies. The country’s GDP to energy consumption ratio clearly shows the need to adopt energy efficiency policies. Taking into account the regulation of excess solar radiation in the desert environment, this study examines the relationship between the shape of different buildings and their energy use. This research was divided into two stages. In the first stage, the ideal building shape for the city of Adrar, in terms of energy consumption, was determined by studying three basic geometric shapes, including square, rectangular, and triangle shapes. According to simulation research conducted using Design Builder (version 6.1.0), a square building was the best shape to maximize energy performance. To analyze the thermal behavior of different building shapes, all structures with expanded shapes were simulated based on the ideal shape discovered in the first stage. Of the three extended alternative cases, the case of the Mini Arrival offers the best energy efficiency and sufficient natural lighting thanks to its 90 cm depth and no vertical offset from the top of the window. By adding design principles to the design process, this study helps improve the energy efficiency of new buildings and also gives another angle on research methods for solving energy performance issues regarding desert buildings.