Why we should allow daylight to shine

Chris Lowe of BDP, tells us about the role of natural light in inspirational, interesting and healthy buildings – and why artificial light doesn’t really cut-it.

Daylight is important to the human condition. It can improve our health, wellbeing, creativity and productivity in both work and education.

How much daylight are you getting right now? If you’re in an average office, it’s probably around 500 lux – less than 1 per cent of what you’d get outside when the sun is out. It’s the same in a classroom. As more and more research shows that exposure to daylight makes us healthier, happier, more creative, more productive and smarter – and as free and abundant as it is – it’s odd that we as a society don’t value it

Ok, maybe we don’t “choose” to restrict daylight – but it’s a constraint imposed by many of the buildings in which we live, work and learn. As architects and design professionals, we have the power to reverse this – and we can start by engaging lighting designers at project inception.

Light has the ability to transform space, and beyond that, it’s integral to our health. According to the Global Human Spaces Report (2015) daylight makes people six per cent more productive and 15 per cent more creative.

We have evolved so that our hormonal cycles follow the sun, and ongoing chronobiological research shows that light has a huge non-visual impact on our bodies – especially since the rediscovery of the ganglion cell in the 1990s. For example, exposure to daylight suppresses melatonin (the hormone associated with sleep) in the day and allows it to be released at night for a restful sleep.

If people don’t get the right amount of light stimulation during the daytime, it puts them out of sync. On a sunny day outside you might receive <100,000 lux, and on a typical cloudy day in Scotland, maybe 10,000 lux. But inside a school classroom, for instance, you might only receive 300–500 lux – and that’s the biological equivalent of being in a black box. That can be detrimental to your biology and has negative health impacts. The bottom line is that daylight is irreplaceable, and it can’t be currently matched with artificial lighting techniques.

Going back a long way, I think daylight was more highly valued. But then we developed mass construction techniques, cantilevered concrete, and architects believed that natural light could be supplemented or replaced with artificial light. It’s taken a long time for people to recognise that it can’t do the same job. People need natural light, views out and higher illuminance levels. So former technological advances have caused daylight design to suffer – but new ones like reactive façades and modular skylight systems are bringing about massive improvements.

The amount of light needed in buildings is very subjective. It’s how the light is distributed throughout the space that’s important and how much light is reflected back from surfaces towards the eye, which can shape people’s perception of space.

Daylight design is both a science and an art, but too often we settle for an engineered solution. Daylight shouldn’t be seen as a constraint but as an inspiration. This is where lighting designers can play their part and assist architects in the creation of beautiful spaces that minimize energy consumption whilst benefitting human health.

Chris Lowe is associate lighting designer at BDP