Natural light is magical. Its ability to mold a space almost eclipses the function of light itself. For eons, humans have shone firelight and other artificial forms of light onto surfaces that need to be seen. But something about being bathed in natural light—especially here in the Pacific Northwest, where the quality of light can change dramatically from one moment to the next—leaves me feeling transformed, like I’m part of some alchemical process. I work a lot with natural materials like wood and stone, and in woodsy, rocky spaces like this, the combination of texture with the quality of light creates a kind of intimacy beyond the sum of its parts.
Using natural light in design is more than just a practical way to achieve illumination. It’s a way to use a living, dynamic material that has texture, depth, and movement. Light’s basic qualities are always in flux—based on the time of day, the season, and even the weather. And while these changes largely determine the look and feel of the lit environment, they also have a huge impact on the unlit one. And that’s where harnessing the artistry of light comes in.
The Light that Plants Need—Biophilic Design Principles and Photobiology.
My first genuine comprehension of the influence of natural daylight emerged from touring a stately edifice up in Scandinavia. I had heard that Scandinavian architecture pays much attention to light, but I was unprepared for the direct experience of how that might feel. This particular building was laid out to utilize every available foot of sunlight, with high, wide windows and surfaces positioned to reflect and amplify light into parts of the room that seemed too far away to have any direct light on them. It was almost as if the light itself were following a kind of choreography to hit as many marks as possible.
Biophilic design goes beyond merely providing lots of good, bright light; it focuses on connecting people indoors with what happens outdoors. To maximize that kind of connection, I’m always thinking about how to orient spaces for optimal exposure to the types of light found in nature. With a wellness retreat I worked on recently, for example, the challenge was to rise up and meet the natural light conditions of its tree-covered setting. The solution? Windows that let in the right amount of light without letting in all the noise of the trees. And by “noise,” I mean the light-capturing ability of the trees themselves.
Biophilic design emphasizes creating a connection to the natural world, which is accomplished, in part, by filtering light in a way that maximizes our experience of it. In true biophilic fashion, the goal here isn’t merely to deliver the same amount of daylight as a standard window would accomplish; it’s to do that while using intelligence, artistry, and, to some extent, simulation so that the space feels as if it’s experiencing the same quality of light you would feel outside. Skylights, in some respects, are the peak of this quest. They bring not just sunlight but also the experience of the changes and moods the sky goes through from dawn till dusk and beyond, into the core of a building.
Clerestory windows are perfect for bringing in natural light without compromising privacy. They are high, narrow windows that sit above eye level, and in spaces like bathrooms, bedrooms, or even yoga studios, they capture natural light beautifully while maintaining the secluded feel that comes from not being able to see in or out of a space. We installed them in my recent project, a downtown yoga studio, to catch the soft, warm early morning light that is such a nice asset to any space. From the outside, you can’t see in at all, and from the inside, you only see an expanse of the sky—which might be a benefit in an urban setting where your opposite neighbor’s views aren’t so serene. We flanked the studio with them on both sides and ran the length of the studio with them across the front, above the doors.
How to Optimize Natural Light for Health and Productivity
Natural light does more than just affect the looks of a space; it impacts our collective and individual well-being in significant, and perhaps even profound, ways. Proper daylighting can elevate a built environment from the merely functional to the almost spiritually restorative. It is hard to overstate the difference between walking into a room filled with bright sunshine and entering one filled only with the dim light of electric lamps. Relying on the latter might even feel a bit oppressive, or at the very least, strangely counter to our biological fitness as creatures of the day. Natural light regulates our circadian rhythms, is a major player in our stress and mental health, and is crucial to the appearance and maintenance of productivity and good mood in any environment, including by all appearances the built kind.
A corporate office renovation project I worked on several years ago really brought home to me the benefits of natural lighting in regard to employee well-being. The predecessor to the newly redesigned office was a space that received scant natural light and relied too much on the harsh glow of fluorescent bulbs. Not at all an energizing way to start the workday! Understandably, the employees who toiled in that dim, sterile atmosphere complained of feeling mentally and physically drained. When we put together the new design concept, which may be too simplistic to call a “retrain the brain” scenario, biophilic principles guided our approach, and we let natural light be the star of the (work)place.
Another essential component of the natural light in this office project is that it is well controlled. Natural light is very dynamic, which means that it can be very difficult to find the right balance between having enough light without having too much. “Too much direct sunlight can cause glare, create hot spots, and even fade materials over time,” Boehm explains. In addition to outfitting the office with larger windows, the design team was careful to complement those windows with different types of window treatments. The main thing is flexibility. And the natural light that fills this office space is designed to work with the demands of the users and the office itself, across a range of times, seasons, and even personalities.
Natural light is a dynamic design element. It is not static, and spaces should reflect its fluidity. In residential design, for instance, light is the first consideration, and the basic question always is, how will the light change as the sun moves across the sky? Saying it this way makes it sound like a straightforward inquiry, but it really leads to so many varied and textured considerations that it’s hard to know where to begin. Thinking of a home as a stage set, I remember a kitchen I once worked on that faced east. Morning light filled it, but it was not how deep or how present that light was that made it a cozy and inviting space; it was that the light being what it was, I was compelled to choose materials—the island and countertops, for instance—that complemented it.
What happens in spaces where natural light can’t seem to reach? This problem often arises in urban settings, and it is here that the architect’s ingenuity must shine through. I once had a commission for a small apartment that had only one side that could access the outside. Given this limitation, there was no way to meaningfully increase the amount of natural light that could reach the space (except for the time we tried leaving the windows open during a hurricane). Instead, we worked with what little light we could get, using light-colored and reflective materials throughout the space to help the light we had travel further and live longer. Mirrors were also integrated into a few key areas to help the available light get around some corners that weren’t really in the line of sight of the windows.
One of my other preferred techniques involves the use of indoor plants to filter light. Large plants, especially those with big leaves, can take the edge off bright, direct sunlight and make it warm and cozy, much like the atmosphere of a forest. I have deployed this strategy in residences and businesses. One place where my light-diffusion technique using live plants was executed beautifully was in the lobby of a boutique hotel. The sunlight that poured through the lobby’s windows and the leaves of the plants created an enchanting light show on the lobby’s surfaces.
The first thing I must say about this is that it was for the beauty of my client’s home. Well-being was an important factor in this design. And light! It is something that we have in abundance, yet we seem to squander it in a society that relies so heavily on technology. Today, you rarely walk into a building that isn’t full of artificial light, even when the sun is shining at its full brightness outside. And then there’s the energy problem: all that artificial light in the evening and morning could be used for something else, put to work in our appearance of darkness. I worked on this project so that the appearance of a candlelit room or the light of a false dawn or dusk wouldn’t impinge on my client’s well-being or their comfort in this space: without the appearance of darkness, there is no light.
In particular, biophilic design can make use of what are called light shelves. These horizontal surfaces, which are positioned beneath windows, function as reflectors that send sunlight deeper into the room. They’ve been used since ancient times in places where sunshine is too direct for comfort. They were popularized again in the early 20th century. And they are one of the few tricks in the book, so to speak, that an architect has to improve not only the quality but also the quantity of daylight that reaches a space.
When I look back at the projects I’ve undertaken, I see a common thread: the nearly magical part that natural light plays in making a space feel alive. I regard light as an untrained but highly effective designer that creates the look and feel of a space without the designer needing to be present. Indeed, light can transform a space without any added materials. Intuitively, one might think of light as just another technical detail of a building. In my estimation, though, when light is carefully considered and intentionally integrated, it is what gives a space its soul.
A library I designed recently posed a real problem in terms of natural light. While libraries require a careful balance of light—enough to read comfortably but not so much that it causes glare or would damage materials—a residential library should also avoid direct light, which can quickly make a space feel too warm. My solution was to play with filtered light, much like what would occur in a forest, which is how we conceived this library in the first place. We placed monumental windows in a room adjacent to the main reading room that offers vistas of the treetops of the shaded area surrounding the library. The soft, diffused light that comes from those windows fills both rooms. It’s a magical effect.
In that project, I also employed light wells, especially at the building’s center where no other options for fenestration could be applied. Light wells are nothing more than vertical shafts that carry natural light from the roof down to the building’s lower levels, and they work spectacularly in spaces that might otherwise fall victim to darkness or claustrophobia. We designed the light wells in the library to act like small atriums, granting passage to light and visually interesting rays of sunshine that would warm the spaces beneath them.
A method I frequently apply to increase natural light is the incorporation of reflective surfaces. Materials such as glass, metal, or even water can bounce sunlight around and intensify it in a space. One project where I did this was for a nature-inspired restaurant. We had a water feature in the dining area, and it was sunlight-cast reflections off the water that created a ceiling of soft ripples. It was warm and inviting, and I really think it made the space feel more alive without being too direct of an effect. Biophilic design principles rely heavily on the use of light and the way it interacts with various materials.
Biophilic design takes advantage of natural light and uses it to interact with the other design elements in a space, particularly color. Natural light is the best light, and it’s worth the effort to incorporate it into your designs as much as possible. People always talk about how natural light makes a space feel bigger. But to be honest, natural light absolutely just makes a space feel better, hands down. I’ve worked in many different contexts, and I can definitely say that there is a palpable quality to a space that has well-distributed natural light. That’s not to say that colored light (e.g., light from lamps) can’t also feel good in a space—it certainly can and does! But natural light combined with colors found outdoors is pretty much a slam dunk.
I have played with natural light in some unexpected ways, using perforated screens and patterned partitions, for instance. They let the light through—descending upon and gracing the space in the kind of ephemeral, unexpected ways one hopes for when working with natural light. But there is something more to these low-tech, high-reward solutions. By using light and shadow in conjunction with walls, I have found that you can create a scene almost anywhere inside of a private residence. Shadows can occur anywhere you want them to, and you can control their size and quality by managing how light passes through the screens and into the space.
I have always been captivated by how natural light can change our one-dimensional perception of small, narrow spaces—particularly hallways and stairwells. I’ve often said the case could be made for light being on par with “the presence of a window” in the building code because a significant amount of daylight is just as important in transforming an interior space from one that feels closed and secretive to one that feels open and safe. I will say, though, that I’ve always been equally fascinated by the prospect of using—even the potential inherent in using—natural light in a way that doesn’t strip the space of any privacy. And in that light, the high window argument is on solid footing.
One of my recent gratifying discoveries in biophilic design is dynamic lighting. It’s the new lighting concept for offices and other interior spaces that lets you simulate the natural passage of light and of dark in a 24-hour period. When we renovated the office I worked in a couple of years ago, we integrated smart glass into our designs. That means we worked with a design that not only gets us a certain amount of light and a certain amount of view but also a certain amount of privacy from the public that moves through the common areas of the office.
No biophilic design can be complete without contemplating how natural light interacts with the life found in nature. When it comes to photosynthesis, plants can hardly be said to be living in the twilight zone. Integrating indoor plants into a design can enhance, to an almost uncanny degree, the feeling of a connection to the natural world. I advocate positioning plants where they can thrive in the kind of light that most humans can’t. I bet you’ve never heard anyone advocate for the “What’s best for the kind of light your indoor plant needs” as a principle of biophilic design. But here I am.
Biophilic design’s most vital and adaptable instrument is natural light. It forms and curates our spatial experiences, guiding us through the rhythms and routines of daily life, as effectively as any intentional architectural move. Just as our distant ancestors did, we rise to the beckoning of the morning light, gathering in the sunlit spaces of our homes to enjoy breakfast and prepare for the day. Good design uses natural light as a partner in giving life to spaces, not just ensuring their functionality but also suffusing them with the warmth and soul that are the hallmarks of good places.
