Window design in architecture: Analysis of energy savings for lighting and visual comfort in residential spaces

•The window geometry and position are analyzed to quantify the energy saving.•Dynamic metrics show a database of energy saving allowed by different windows.•Horizontal openings produce higher energy saving than other window shapes.•Energy saving is directly proportional to reflectance in the back of the room.•Energy saving according to window orientation and location is quantified. Window design is decisive in providing appropriate visual comfort for occupants and sufficient energy savings in electric lighting. In daylighting, visual comfort is dependent on the maximum daylight autonomy. Moreover, energy consumption in electric lighting relies on daylight autonomy. The aim of this research is to quantify these metrics in a residential room for different window models and analyze the results obtained. The surface reflectance and the geometry of the window are variable. DaySim 3.2 lighting program provides the simulations of the room model according to different orientations and weather conditions. Following the trials, it was concluded that daylight autonomy is proportional to the glass surface and reflectance of surfaces at the back of the room, while its influence near the façade is negligible. However, energy consumption does not depend on window shape. It is also concluded that windows located higher up result in higher illuminance at the back of the room than those in centered locations. The conclusions of this research are contrasted with the analysis of daylight metrics for different locations and orientations of the window.