Experiments and questionnaires were conducted at an elementary school to determine the effect of environment monitoring system on ventilation behavior. The LED lamp display according to the carbon dioxide concentration served as a criterion for decision-making on ventilation behavior, and the percentage of carbon dioxide concentrations exceeding the standard (1,000 ppm) decreased for many classrooms. Alternatively, in some classrooms, excessive ventilation was fixed, and the thermal environment was also improved. Moreover, the children’s involvement in opening windows for ventilation increased.
