The paper presents the calculus program expert kind “SPATIAL GLAZING” for the modeling and simulation of the physical spatial phenomena of thermal transfer through structures with complex formation, for the estimation of the heat flow and thermal resistance, for determination of the energetic performance of windows in divers placing modes in the walls of the building envelope. The findings and the measurements made upon the same window type with the same energetic performances taken from the catalogue, for different conditions in exploitation, led us to the conclusion that the energetic performance of a type of window is much influenced by the contour conditions in which is placed and where is in exploitation. The necessity and the suitability of the automaton calculus program was imposed upon the need of explaining the differences in behavior of the same window type which has been placed in divers constructive solutions for walls and for divers placing positions of the same window type in the wall thickness. The calculus program expert kind “SPATIAL GLAZING” uses and develops other automaton calculus programs made by our research collective from the department of Physics of Constructions in the last 30 years of activity in the physics building field. The numerical method used is the one for the energetic equilibrium in each node of the plane or spatial digitization network for the ensemble window- wall. The automaton calculus program takes into consideration the stipulations in accordance with EN ISO 10211/1-95 regarding the realization mode of the digitization network and the estimation mode for the flows equilibrium in the calculus network nodes. The automaton calculus program “SPATIAL GLAZING” uses the profiles geometry and the calorific characteristics identified from a data library and post them in the structure of the analyzed ensemble. The design heat characteristics of the building materials used for our study were those taken from the European standards regarding the energy performance of buildings. The results obtained with the automaton calculus program “SPATIAL GLAZING”, are presented numerical and graphics form under curved shapes and isothermal surfaces. Because of its “easy and friendly” nature, staff with medium knowledge in the computer usage can use the calculus program. The calculus program “SPATIAL GLAZING”, was used for designing new window profiles, at designing new buildings, for determining the energetic performance of envelope elements of new buildings and for energetic rehabilitation of the existing ones. The calculus program “SPATIAL GLAZING”, represents a valuable implement for establishing the energetic performance of windows in actual conditions for exploitation, for the four standardized climatic zones in Romania: I zone -12oC, II zone -15 oC, III zone -18 oC and IV zone -21oC. The use of the calculus program gives structural solutions for the for the ensemble window- wall which have a direct and favorable effect upon energy economics in building exploitation and for reducing the pollution emissions in the atmosphere.