This paper contains a thermal diagnostic method based on a new approach of wall discretization for buildings that predict energy behaviors, examined in both summer and winter periods. A computational approach has been adapted to determine the temperature distribution through the multilayered walls of the building. A new equation collects information relating to the internal temperature in relation to the external conditions. Moreover, the building's envelope has been deduced depending on conversion parametric, resistive parametric and generation coefficients. The thermal behavior of a cubic building designed in Fez- (Morocco) has been diagnosed to a dynamic state using the meteorological conditions. The external conditions, such as solar irradiation, natural convection and air exchange, have been modeled to indicate time related variations, step by step, that match the thermal model. In pursuance of interior thermal comfort in term of internal temperature, results shows that the building's should be oriented towards south with 26% of glazed surface, and air gaps thickness that is equal to 2 cm of polystyrene. In addition, the walls should be 0.84 W m−2 °C−1 instead of 0.7 W m−2 °C−1, which is the recommended value by the Moroccan Thermal Regulation of Construction.
