The school's new buildings cost more than £20 million but one window which broke the week after the classrooms opened in January has still not been fixed, she said. A separate study by Reading University tested the reaction times and memory of pupils in rooms with high levels of CO2. Professor Derek Clements-Croome, who led the research, said: "When the CO2 was very high, the reaction times would slow and memory would be affected. The kids would also get drowsier.