Several studies have shown that the energy use due to ventilation of classrooms can be reduced with 50 to 60 % with well designed demand controlled ventilation (DCV) compared with constant air volume (CAV), presupposed traditional classroom based education. However, the use of the school areas has changed radically the last decade, and the energy saving potential in modern schools needs to be reanalyzed. In addition, technology advances with sensors, communication and control systems open up new opportunities for more robust and energy efficient DCV-systems. Furthermore, the decision makers will probably not aim to utilize the potential to reduce energy use with demand controlled ventilation if they do not have sufficient knowledge about the energy saving potential.