Abstract-The aim of this research is to quantify the daylight autonomy and the useful daylight illuminance produced inside a room for different models of windows, and to conduct an analysis of the results obtained. The shape, size and position of the window are variable, as is the reflectance of the inner surfaces of the room. A total of 28 simulations are provided by the lighting simulation program DaySim 3.2. After trials it was concluded that the daylight autonomy is directly proportional to the glass surface in the back of the room, while its influence in the zone near the faç ade is negligible. However, the energy saving does not depend on the window shape. It is also concluded that the windows in the upper position allow higher luminance at the back of the room than those in centered locations.Index Terms-Daylight autonomy, energy saving, useful daylight illuminance, window.