One of the main qualities of daylight is its variability. Good daylight design accounts for changes that happen throughout the day and the seasons, to deliver a consistent and comfortable light level in the space. Natural lighting conditions are never exactly the same and this makes it also difficult to predict. Thanks to a more sustainable approach in every sector of our societies and an increased awareness of its benefits, daylight is back on the agenda in recent years. Contemporary design reintroduces daylight into the mainstream of architecture. In this context a new standard was developed at European level to support and stimulate this evolution.