School energy efficiency measures, such as adoption of several energy efficiency measurements, represent a driver for increasing the risk of overheating hence has a significant impact on the student learning and health. In order to deal with the problem realistically, it is essential to investigate energy audits based on extensive case studies. Analysis data of 150 energy audit of schools building stock were conducted, to examine the energy consumption performance and internal environment of the schools constructed in different periods from 1873 to 1901. Energy audit techniques were carried out to identify any energy conservation opportunities (ECOs). Level 1 (walk-through assessment), level 2 (survey and data analysis) audits and thermal images data for interiors were conducted over all building zones. Results of 150 schools case studies showed an increased on the pattern of the energy used and most of the internal environment experience overheating, this highlight the issues of the reduction of fresh air flow rates