Consider the sun. This mass of incandescent gas, this giant nuclear furnace – to borrow from an old children’s song – provides the light and heat that drives so much of life on Earth.
When it comes to our built environment – the office buildings, hotels, educational facilities, and residences where we spend the vast majority of our days – the natural light provided by the sun is too often an afterthought, replaced by the incandescent, fluorescent, and LED bulbs powered by electricity. We have windows, but – depending on the structure – the daylight they let in can be spotty and inefficient.
It doesn’t have to be this way. Indeed, optimising daylight can benefit lighting design in a host of ways. It helps structures meet green building standards and sustainability goals by saving on energy costs. Studies have shown it’s highly desired by employees, and it offers designers flexibility in creating and managing spaces, whether it’s an open-office layout or a simple hotel room. Daylighting is truly the most impactful thing we can do in lighting design.
The value of shades
The most obvious example of daylight control – and perhaps the oldest – is shading.
In the first century AD, the Romans invented a solution – the Velarium, a retractable, fabric awning that extended around the entire stadium to protect spectators from the broiling sun. These structures are considered some of the first shades. Other civilisations improved on the technology – placing them in fenestrations, developing ways of contracting them, even using them as decorative art, tet they remain underrated tools.
Shades don’t just block out the sun, they can reduce and stabilise temperature and tweak views, even contribute to a building’s aesthetics.
These days, shades are commonplace to the curtain-wall skyscrapers you’ll find in every city. But even now they’re not used as efficiently as they could be. Daylight is highly variable, changing with the season, the weather, the time of day, and the geographic location, which means that successful daylight control in one location and time may fail at another.
In addition, many shading systems are controlled manually, and are dependent on human actions. The uncoordinated raising and lowering of shades makes a building exterior look like an aesthetic mess.
Automation can alleviate many of these issues. A daylighting strategy that includes sensors, timers, and daylight-responsive software can work with a building management system to provide maximum daylighting and light efficiency. By raising and lowering the shades in unison, automation can also help eliminate the snaggle-toothed look that a building presents to the outside.
Shades can also help reduce solar heat gain. Modern commercial buildings, lined with windows, handle the heat through a variety of climate-control options, including HVAC systems and treated glass. But window coverings such as blinds, drapes and shades can play a substantial role. Properly installed shades insulate rooms during bright summer days – and, for that matter, can do the same during bright winter days. Shades coated with reflective material work best to repel the sun’s rays during the scorching summer months. In the winter they can let the sunshine in. Either way, the shade fabric is key to this control.
Shades are also a defense against uncomfortable glare. They can be manufactured with a degree of openness – the density of the shade’s weave – that can mitigate glare, and also come in a variety of colours which maintain access to the view outside. That’s important, because studies have indicated that views are one of office workers’ most desired amenities.
Access to the outside
Indeed, access to views has become an increasingly important part of modern building and lighting design. Ideally the view is of greenery, feeding into what’s been termed “biophilia” – an innate human connection to nature. Any views of the outside are welcome – ultimately, they are a connection to the world.
Research has borne this out. One worker performance study indicated that workers with the best possible view perform 10% to 25% better on tests of mental function and memory recall than participants with no view. Another noted that having access to views improves worker satisfaction. A third study said increased access to daylight and views can contribute to a sense of well-being.
With the use of shades and other lighting controls, these aspects of building design can be made an essential part of the overall plan, not an afterthought.
Creating a seamless flow of natural light
Still, optimising daylight can be a moving target. The intensity and colour temperature of daylight change during the day. These differences may clash with a building’s electric lighting.
Thankfully, as LED technology improves, incandescents and fluorescents are being phased out. Not only are LEDs more energy efficient than either, the light they produce can be “tuned” to promote comfort and engagement.
At the same time, automated lighting controls, such as sensors and timeclocks, can increase or decrease the intensity of electric lights based on the daylight already coming through the windows. Together, these solutions serve to create a seamless flow of natural light into a space, whether you’re next to the window or many metres away.
Though the concept of daylight optimisation isn’t new, it’s taken on an increased urgency in recent years.
The emphasis on sustainability has given daylighting an important role, since it helps contribute to energy savings by diminishing the need for electric lighting and even heating and air-conditioning. Moreover, the rise of “human-centric” standards, such as WELL and BREEAM, have renewed the focus on daylight given our innate response to illumination.
Simply put, the idea is to think of daylight as part of a holistic solution, as indispensable to space utilisation as task lighting, personal controls, and automation. The sun may remain dominant in our lives, but that doesn’t mean we can’t bend its will for our benefit.