The Casbah of Algiers is classified world heritage in 1992. Their constructive typologies and specific equipment's of walls distinguish its traditional dwellings. They are mainly distinguished by the principles of eco-design and climatic adaptability. The present work aims knowing the influence of a traditional wall on the energetic performances of a dwelling of the Casbah of Algiers through different compositions in order to choose the most suitable typology for the ecological and environmental question. The adopted methodology is structured on the characterization of materials and an evaluation, through a series of simulations, of the influence of thermal inertia on the energy performances. The results obtained allowed us to enrich the ecological framework of the materials by determining the optimal composition to the eco-design for a better revaluation of our built inheritance and a better safeguarding of environmental resources.