The effect of light, or to be precise, of daylight, on our well-being cannot be denied. When the sun shines, we feel happier and more energetic. When it’s grey outside, our mood tends to swing in the other direction – facts that should also be kept in mind when planning natural light in buildings.
70 – 80 – 90. Three numbers that have a significant impact on the way we feel. Why? Because we spend 90 per cent of our time in buildings. And because sight is the sense that gives us access to between 70 and 80 per cent of all our information. It’s hardly surprising that daylight or natural light lets us experience architecture and rooms in a completely different way, and it has a direct impact on our well-being.
So natural light should be an integral part of planning from the very start, requiring support from architects and engineers – this was the opinion expressed by natural light experts from Bartenbach and Schüco during a DGNB Discourse Event. The meeting took place under the title Between comfort, well-being and energy conservation: the importance of natural light in sustainable building.
Daylight dictates our internal clocks

Prof. Winfried Heusler of Schüco at the DGNB Discourse Event on natural light
Our circadian rhythms are driven by daylight. We feel awake when it’s light and tired when it gets dark. Although this sounds simplistic, it can actually be explained by the biological effects of light. Sunshine stimulates serotonin production. And as it gets darker in the evening, the dim light stimulates our bodies’ production of melatonin, a hormone that controls sleep and regeneration. To put it briefly, the dynamics of daylight have a positive effect on us and should be integrated into our buildings. One approach that can be applied here is called circadian lighting. This is adaptive lighting that follows the cycle of day and night, which has a positive effect on our bodies.
“Natural light isn’t a business. Natural light is an attitude,” said Prof. Winfried Heusler, who heads up the Global Building Excellence department at Schüco and has worked for the company since 1998. He added that there’s no denying the positive influence of natural light on our performance and motivation levels. In combination with visual contact to the outside world, it also influences our creativity.
Light in the DGNB system
“Approaches such as the DGNB system are prompting a shift in how we think, in our willingness to accept higher costs associated with the effective use of natural light,” said Andreas Danler, head of the Lighting Applications department at Bartenbach.
The DGNB System takes the use of daylight into account in many areas. This is because compared to artificial light, effective use of natural light is a major potential to save money, especially given environmental impacts and costs over the entire life cycle of a building. Daylight plays a special role in socio-cultural and functional quality, first and foremost under the criterion of visual comfort, which is aimed at ensuring all occupied areas have a sufficient and uninterrupted supply of natural and artificial light. This ranges from the availability of natural light throughout the entire building to an absence of glare and having visual contact with the outside world. The experts also pointed out that natural light has another advantage over artificial light – it may go out in the evening, but it always comes back on in the morning.