Circadian rhythms are the biological, behavioural and mental processes that keep people happy and healthy. They’re controlled by the suprachiasmatic nucleus (SCN), a small region in the front of the brain that works like an alarm clock for the body, telling the brain which hormones to produce throughout the day, managing the sleep and wake cycles, productivity and alertness, body temperature and digestive system.
Environmental factors, particularly lighting, have a major impact on circadian rhythms. In the natural order of things, daylight is blue in the morning and on clear sunny days. As the sun sets, it becomes softer and redder. This slow change in colour and light intensity throughout the day sends visual signals to the brain that regulate the circadian rhythm. If those rhythms are disrupted, so is a person’s sleep, which translates to negative impacts on daytime productivity, mood and concentration as well as increasing the odds of depression, diabetes and cardiovascular problems.
For these reasons, when Vincent Nowak, co-founder of Flow Architecture, designs a building, he relies on natural light as much as he can. “It’s not only the light itself; the views to the outside are important. Daylight comes in different intensities and colours. It also changes continuously throughout the day and the seasons. It’s of so much importance that one feels a part of an ever-changing natural cycle of light,” he says.
“Artificial lighting is a whole different story. It misses the views and cycles but offers much more flexibility when it comes to controlling the light levels and staging the design. The right mix is based on a good understanding of what each type does best. It is not so much daylight versus artificial light – it’s more how each type is used in the context.”
There are several factors that combine to strike this balance, according to Shashank Singal of New York-based architectural lighting design studio Lumen Architecture. “First is the purpose of the space,” he says. “Is it office space or residential? Is it for retail or art? Each space has its own requirements and guidelines to follow.”
The location of the building and quality of light in its surroundings must also be considered. “The length of the days, the latitude and longitude, whether you’re near the water or in a desert. All of those things bring a certain quality of light into the space,” Singal explains.
Materials and finishes also interface with the light that’s coming in and impact the quality of electric light that would need to installed, but it’s the ‘skin’ of the building that’s perhaps the most important factor. “It’s all about the size of the openings, what is the barrier material separating the outside from the inside and what’s the depth of the transition,” says Singal.
From intuition to simulation
Historically, architects have used their intuitive understanding of the natural cycles of light – where the sun is in the sky at a particular time of day and what that means for both the aesthetics of a design and the well-being of its inhabitants – to feel their way into effective architectural lighting schemes. For Nowak, lighting should always be part of the architectural narrative of the building, underlining it and amplifying the message – it should not start a design narrative that is only loosely connected to the intention of the building.
But as design and visualisation tools have become cheaper and easier to use, and regulations like the LEED and WELL building standards have codified access to natural light – with building owners obliged to demonstrate how a lighting design performs in terms of quantifiable metrics – daylighting considerations have become a much more tangible factor in the design process.
“Simulating natural or artificial light within a computer-generated 3D environment is nothing new. The technology is at least 25–30 years old,” Nowak says. “What is new is that one doesn’t need to be an expert to run daylight simulations anymore. One can simulate the lighting design using virtual or augmented reality to develop the design narrative and share ideas. It’s nothing new – but all this is now at our fingertips.”
For Nowak, there are two parts to the story. “Visualisation tools play an important role to understand a given design better. You understand the light levels, you can share the design with your client and you might develop the design further once you see it in a virtual environment. This is exciting, but it affects more the ‘front end’ of the design.”
He thinks back end generative design techniques, which enable architects to integrate lighting at a much earlier stage of the design process, will be the real gamechangers. “These allow you to establish feedback loops within a set of design parameters,” he explains. For example, if you were designing the louvres of a building, you could simulate the sun in the computer environment, so you would get the right shading at the right time. Or, when Nowak was designing Light Falls, a London house conversion, in which he stacked the living spaces on top of each other to maximise natural light, computer modelling helped him understand where the sun was coming from, what the relevant angles were and how the shadow fell deep within the building.
Both Singal and Nowak use visual programming language and environment Grasshopper, which runs with the Rhino 3D computer-aided design (CAD) application, to embed daylighting considerations into the design process. Tools and plug-ins such as Honeybee, Ladybug and DIVA help them perform many different daylighting calculations and rapidly test a wide set of design options.
“In a way, it’s common knowledge – you don’t need a computer to tell you,” Nowak says. “But a computer can help you to refine aspects of [a lighting design] or confirm aspects of it, or prove your thoughts to yourself and to your client who is paying for the party.”
Set standards for urban design
Design and visualisation tools are also useful on the urban design level. “You can see the impact on the interdependence of buildings and buildings overshadowing one another,” Singal says. “I think these tools are really helping to set standards for new cities as to how wide our streets should be and how tall our buildings should be so that we’re not shadowing the streets, and our parks and open spaces are still open,” he says.
In 2019, Singal spoke at the Professional Lighting Design Convention (PLDC) in Rotterdam about a study he’d conducted into the impact tall buildings could have on the light levels received by the Brooklyn Botanic Gardens. When they were built, regulations came in stipulating that no building on the street across from the gardens could be more than seven storeys high so they wouldn’t overshadow the nurseries on the edge of the site. When a developer proposed an almost 40-storey building, Singal used Rhino and Grasshopper tools to calculate the precise impact this would have.
“What I found was that about 10% of the total daylight received by the greenhouse would be cut off by just that one building,” he says. “But what’s more important is that if you begin to break the rules around sevenstorey buildings on that street and everyone built taller buildings, it would really impact the greenhouses very adversely.”
Make smart lighting smarter
Another technological advancement that both Singal and Nowak will be keeping an eye on over the next few years is automated lighting controls.
“A lot is happening when it comes to integrating lighting with all the different systems that are going on within buildings,” Singal says. “Sensors gather information so the electric light turns off when there’s adequate daylight in the space and comes on in the evening. Similarly, if the building senses there’s too much heat, it may drop the shades or the AC might pick up.
“There are all these algorithms built in, which takes away the manual control from a lot of these situations. It feeds into the building management system where all this data can be gathered and analysed. Right now, everyone is rushing to gather as much data as they can.”However, Nowak is withholding judgement until smart switches and lighting controls get a little bit smarter. “At this point in time and based on my practical experience, home automation is flakey and expensive. Many examples I have seen are hardly convincing, on a practical level and from a designer’s point of view,” he says. “But it will come. Prices will drop, people will learn how to design with it and it will also become more reliable. I have difficulties to grasp what it will lead us to – that is what I am incredibly curious to see.”