The thesis deals with the thermal analysis of a building envelope, using the software tool THERM 7.5. The building envelope is drawn in the AutoCAD program, using the point cloud acquired by means of laser scanning. Three profiles of the building envelope are drawn, each with a different degree of division: the profile presenting the ideal building envelope (minimal division); the profile presenting the model of the building in question; and the profile presenting the real state, which is based on the point cloud from the 3D scanning. For each profile, 6 crossings are modelled and analysed in THERM. The crossings are geometrically modelled according to SIST EN ISO 10211:2017. The results of the 2D thermal analysis are presented in the form of contour lines, thermographic drawing of the thermal field, heat flux vectors and intensity of the heat flux. Based on the acquired results, it can be concluded that the division in the case of the building in question has an effect on the change of the thermal field in the building envelope and consequently on heat flux and heat loss of the whole building. The heat flux is smallest in the idealized profile. A dynamic building envelope affects the heat flux to increase, especially through the parts of the building, where the wall is moved inside the building or where the reinforced concrete plate continues through the wall to the exterior. In such cases the thermal conduction increases locally, which consequently affects the thermal efficiency to decrease.