Abstract Learning performance is strongly related to thermal comfort and lighting conditions of classrooms. Poor facade design can result in high indoor temperatures or insufficient access to natural light. To maintain the required temperatures and illuminance levels in such rooms may require intensive use of artificial lighting and active cooling systems, which are energy-intensive, costly to install, operate and maintain. The purpose of this study was to determine essential parameters and facade design options that ensure overheating prevention and fulfil daylight requirements in classrooms without mechanical cooling. The present study is based on simulations of a parametric room model with variable dimensions and orientations. Facade glazing solutions with optimal combination of solar factor and visible light transmittance were used to minimize overheating risk and maximize natural lighting impact. For east, south and west oriented facades, the effect of horizontal shading was also analysed. Overheating assessment through indoor temperature simulations was conducted with dynamic simulation software IDA ICE, daylighting was simulated with DIVA4 coupled with Grasshopper software. Results show that classrooms without mechanical cooling require in depth analysis to determine satisfying solutions for both overheating and daylighting criteria. The results of this paper can be used for early stage facade design guide for school buildings or similar use free-running buildings.