Abstract: Within the context of designing a sustainable school, technical studies that address questions of air quality, educational performance and wellbeing challenge the trend toward providing for natural ventilation. This paper critically examines research literature that suggests that temperature and air quality are, in a large proportion of classrooms, so poor as to have a negative effect on children’s health and educational performance. Evidence in support of mechanical systems that control air quality contradicts a recent increase in natural ventilation, proposed as a means to conserve energy consumption in schools. Indoor Air Quality (IAQ) is generally not stressed, or indeed challenged, in the design of sustainable schools, but the questions of internal and external air pollution, common modern diseases in children, and optimizing learning potential, raise important issues in the drive to reduce schools’ energy consumption.