[en] With increasing concern for energy savings in universities, operational solutions, such as control strategies and occupant interventions, have been recommended to reduce energy use, due to the limited responsibilities of faculties and students for energy saving. Additionally, the energy-efficient allocation of classrooms can contribute to achieving further energy saving, because they have different spatial and functional capacities, which result in variation in energy use. In this context, course timetabling can be regarded as a basic source of allocating specific classrooms to lectures. However, there have been few attempts to consider spatial and functional capacities related to energy use in classrooms. Further, little is known about investigating the impact of course timetabling on energy consumption in classrooms. Therefore, this research proposes an energy efficiency-based course timetabling algorithm that identifies an optimal timetable in terms of energy use. The experimental results using the proposed algorithms make it evident that the optimal timetable produces 4% energy saving during cooling and heating season compared to the existing timetable. In addition, more energy savings up to 5.0% are achieved by mitigating hard constraints. The developed algorithm allows for administration staff and facility managers to schedule a course timetable that achieves energy savings in university buildings. - Highlights: • A course timetabling algorithm to reduce energy use in universities is presented. • The proposed algorithm shows 4% energy saving during heating and cooling season. • Further energy saving up to 5% is obtained after mitigating hard constraints.