Light, or the absence of light, not only determines what we see, it is also one of the most import factors influencing our sense of well-being. Our behavior, our moods and our health are seriously affected by light conditions. The intensity and duration of natural daylight make us 'feel better' in summer than in winter, when days are shorter. Daylight provides us with information as to the weather and the time of day, which is considered a very important input for the well-being of occupants of office buildings.

It is therefore logical that people prefer to have their desk in the vicinity of a window, where natural light levels are the highest, even if unwanted side effects have to be taken into account.