I propose to delve a bit more in, probably, the most important architectural element in daylighting: the window. So far we have made two previous notes, as follows:
We will develop the study of the height of the window and how it influences in daylight. Below we can see the model of an office where a longitudinal window is located. The window size is changing from 10% of the façade surface to 75%:
As can be seen, the windows that are between 10 and 20% of the façade surface (equivalent to 4 and 8% of the floor area) hardly provide enough natural lighting.
A window which occupies between 30% and 40% of the façade surface (equivalent to 12 and 16% of the floor surface) achieves an acceptable illuminance, since approximately half of the office is over 300 lux. Windows of larger sizes allows higher luminance. This is shown in false color map that measures the reflected luminance:
Note that the higher the window lintel, the deeper the light, as we deducted in Window Design I.
This work has been developed by the New Buildings Institute, which has done a great job in collaboration with the University of Idaho and Washington. My sincere congratulations for this study.
We will continue studying the windows in the next notes.