After the simulation and the construction of a building, the quality can be proved ultimately only during actual operation. Well-being and absence of damage depend in large part on the actual inner climate under real conditions. Specific calculation can lead to the preparation of an objectification of users' well-being and to a damage assessment, either by discrepancy from the requirements or by climate-related building damages. A Specific optimization can be tailored on the single project. The actual art of measurement, however, lies in the interpretation. When evaluating the measurement results, the competence is harvested from various other simulation and planning projects.