A classroom can be viewed as a mini-ecosystem entity, having its own climate. There are external and internal factors influencing the climate of the classroom. External factors include outside temperature and intensity of sunlight falling through the windows, heating up the classroom interior. Internal factors include the temperature of the heating radiators in the room, number of people staying and breathing in the classroom, the presence of plants to regenerate oxygen from ambient air, just to name a few. And there are control mechanisms which influence the classroom’s climate. These include the level of physical activity inside the classroom, the time duration until a window is opened and provisions to shade the interior from direct sunlight. In this project characteristics like temperature, humidity and CO2 content are measured and stored over time. The data is being analyzed, conclusions are drawn and preventive actions are defined to preserve a healthy climate in the classroom.