Control is executed with the availability of obligatory temperature gradient between inner and external surfaces of structures. In this case the best results are obtained for cold seasons in the presence of heating system. The thermograms of typical defects such as butt joint low quality between panels, brick and concrete components of building as well as water and air leakages are presented. Thermal testing enables also to determine the real heat conductivity of walls, the panel structure the thermal insulation seam quality, the tube failure, etc.