In recent years there has been an increase in the number of apartments in Sweden. The officials are estimating that approximately 1000 primary schools need to be built to meet the 20% increase in students. Facing the rising demand; my thesis makes a contribution to sustainable school design via optimisation of the building orientation.This study utilises Rhinoceros with Grasshopper visual programming language alongside Ladybug, Honeybee and Owl scripts, as well as Climate Studio plugin. The environmental performance analysis software’s results include horizontal and vertical illuminance, Daylight Factor, as well as melanopic Equivalent Daylight (D65) Illuminance. Those findings are further supported with on-site measurements and observations in Iggesund school.