The essence of architectural design rests upon in kind of manipulation between dualism central core and external envelope of any architectural composition; there are some compositions that are concerned with the external envelope,while other compositions the outer shell is result of the interned division. Besides there are other compositions that blend the central core and the external envelope in a harmonious dialogue. This combination between central core and the external envelope touch this diversity in houses of Biskra city through different periods of time to create a comfortable thermal environment.The dry areas, which are distributed on a large scale over the space of Algeria, characterized by climate is hot and dry. We found Morphological diversity in houses of this region that reflects primarily adaptation to climatic conditions, social and economic through different periods.In our research, we depend on the experimental method through digital simulation technology program ECOTECT to calculate data, for various thermal models. in addition in the selection of network studied models we adopted to the variables morphology of both core and the external envelope of the dwelling which are: 1) the oceanic layer, 2) type of the core 3) type of the external envelope. Then we calculated the temperature of various houses layers to make comparisons between various layers and various models.The results of this study came to show the laws that control heat in the atmosphere and that is affected by alphabet elements of local architecture of Biskra region. These laws allow the architect to manipulate to these elements to search for improved thermal yield of the building and control of energy consumption in the range of what is available to him.