The Building materials are mostly porous media. Some are also hygroscopic, which can cause significant damage to buildings and alter indoor air quality, with health consequences. The study of coupled heat and mass transfer in these porous media is crucial in various fields, particularly for capillary materials, rocks, soils, and building materials. The behavior of these materials is closely linked to their thermal, physical and hygroscopic properties and their chemical composition. When designing building walls, it’s essential to use numerical simulation tools to predict their hygrothermal behavior under real conditions. This paper focuses on analyzing the water behavior and thermal performance of a porous wall tested with different insulators. The impacts of the position and nature of the insulator were studied. A mathematical model was proposed. The results of the model are consistent with data from the literature. The results showed that interior insulation has no impact on the water behavior of the material but contributes to warming the wall. Exterior insulation has an impact on the thermal behavior and thermal performance of the wall. The nature of the insulation also impacts water behavior.