Visible benefits

Light is more than just physical, it affects us biologically, and can significantly enhance our lives. Natalie Goodridge at Lamilux UK looks at the relative benefits of natural versus artificial light for occupant wellbeing

While light gives biological benefits, there are also proven psychological benefits linked to it. Obviously, bright summer days lift spirits, while a grey winter’s day tends to have a negative effect on your mood.

However, what exactly is light? Even from a purely physical point of view, light is not straightforward because light is both a wave and a particle. Yet we only see a small part of the light spectrum and much of what the sun sends to us, eight minutes later, remains hidden from the human eye. This includes low-frequency infrared radiation as well as high-frequency ultraviolet radiation. 

This is important in understanding why daylight and artificial light are fundamentally different. Artificial light covers a much narrower spectrum than sunlight, however, due to the ability of our eyes and our lack of perception outside the visible spectrum, this fact remains hidden from us at first glance. Also important for our sensory perception of different lights is the brightness and colour of spectral light, because these are decisive factors for how the mind responds to the quality of light. We only see light: every colour we perceive is only the reflection of light in space. So light is always present, and is everywhere around us.

Artificial light/daylight – what is the difference?

There are some significant differences between natural daylight and artificial light – most importantly, intensity and spectrum. The full light spectrum can only be found in daylight, however bright sunlight is not necessary – an overcast winter’s day will still provide better light than bright artificial office lighting. This natural daylight not only lifts the mood and helps the body produce vitamin D, but it is also better for the eyes, and productivity.

Fonts are easier to read, and colours easier to distinguish, in daylight than in artificial light. Also, our eyes do not have to strain as they would do in the light of a lamp. The white light colour of the midday sun, or an overcast day, is rather cool, and provides clear and unfiltered colour perception. Natural light is accordingly always better than artificial light.

‘The inner clock’: light as a natural wake-up call

You can not only see light, but more importantly feel how vital light is for human existence. The waking and resting phases of human beings are anchored in biology, and can be supported in a completely natural way. 

Large, bright rooms which are flooded with natural daylight release hormones that make us more alert, active and productive. This is not only an ideal factor in the workplace, but also makes a big difference for schools, hospitals and, of course, the living room at home. 

Daylight affects your productivity not only because of the positive effects, but also because of negative effects. Our internal clock is synchronised to the natural day, our productivity increases in the cooler and more intense light of the morning sun and decreases towards the evening.

Where should daylight enter our buildings?

Natural daylight is therefore the best way to work more productively and healthily, but not all light sources are equally suitable for this. Daylight in any form is superior to artificial light sources, but windows in the wall are often not enough. The setting of your site will be influential on your daylight design strategy. If you are designing on new greenfield land you have lots of scope to design your building and its orientation for energy efficiency and optimum daylight. However, when working with existing sites, the sky may become more valuable to utilise as a light source. Especially in larger rooms, not enough daylight can penetrate into the depth of the room from the wall. 

Additionally, we only ever capture part of the sky through wall windows. The University of Roehampton Library project illustrated here is a perfect example of designing for light from above, flooding the room with natural daylight. Even small skylight openings have the same effect as much larger side windows and can easily illuminate the entire room on the top floors or in single-storey buildings. And this is precisely where rooflight solutions demonstrate their efficiency.

Bright rooms appear larger – as well as more charming – natural daylight helps us to concentrate, and creates the hormonal basis for a healthy mind and a balanced day-night rhythm. Rooflight professionals will demonstrate how to bring daylight into a design as early as the planning phase, or how to easily retrofit elegant flat roof skylights.

Natalie Goodridge is marketing manager at Lamilux UK