In a hot and dry climate, the design and construction of buildings involve the adoption of combination between shape of building envelope and construction materials. The objective of this work is to study the thermal behavior of a multilayer wall submitted to varying climatic conditions. We have proposed four configurations of an element of an outer wall. A numerical simulation was used to understand the phenomenon of thermal inertia, especially its influence on the resulting temperatures. The study is based on the modeling of heat transfer in a 2D unsteady-state using a computational fluid dynamics (CFD) code. The comparison of numerical results was affected with an available experimental data and shows a satisfactory agreement. In addition, this work highlights the importance of the study of the thermal inertia of the wall in order to ensure a comfortable indoor climate of building located in hot and dry climate.