Figure 1: The atrium of a Roman domus (House of Menander, Pompeii). An opening in the roof (compluvium) brought sunlight and rainwater into the cavaedium (atrium) to light the interior rooms and feed the shallow impluvium pool. Such atriums passively illuminated, cooled and ventilated the house long before glass windows became common.
Throughout history and cultures, the light well has persistently emerged as an architectural solution to bring daylight and air into buildings. In the ancient Roman domus, a central atrium served as a primitive light well. Surrounded by closed rooms, the open roof of the atrium let in sun and rain, which collected in a central basin of impluvium. This design was born out of a practical need: in dense Roman cities, houses had few exterior windows and looked inside for light and water. The atrium became the social heart of the home – a space to receive guests and conduct rituals – but it was fundamentally a climate device, a cultural response to the constraints of urban life and the Mediterranean heat. It allowed urban Romans to enjoy filtered daylight and natural ventilation in privacy, at a time when external walls faced narrow streets and security was a concern. During this period, the light well took the form of an open-air courtyard, balancing functional demands with social importance.
Figure 2: An Islamic courtyard with its central fountain and hanging chandelier (Marrakech Museum, Morocco). Inward-facing courtyards in traditional Islamic and Ottoman houses allow sunlight and air to penetrate while maintaining family privacy. Tile mosaics and water features cooled and reflected light, creating an oasis-like atmosphere.
Beyond Rome, the concept developed under different climates and cultural values. In the Islamic world, the sahn (inner courtyard) became common in houses everywhere from Fez to Aleppo. Bordered by arcades or rooms, these courtyards provided a shaded, private core where breezes and daylight could enter the house without exposing the interior to public view. This was a direct response to the Islamic emphasis on privacy – the “architecture of the veil” – where modest street facades concealed the luxuriant inner courtyards. One of the most important benefits of these interior courtyards was their ability to admit the sun and encourage air circulation “without giving insight into the internal events of the house”. In hot and arid climates, courtyard geometry and materials moderated extremes: thick walls provided thermal mass, central fountains or gardens humidified and cooled the air. Ottoman houses inherited this tradition; whether in a courtyard house in Damascus or an Ottoman mansion in Bursa, families organized life around a light-filled courtyard (sometimes with a retractable roof or open veranda). The light well here was in fact a microcosm – a safe room for family life, sized and decorated according to the ideals of the culture, open to the sky. It met climatic needs by naturally daylighting and cooling the house, and social needs by creating an intimate outdoor room. Throughout these civilizations, we see light wells growing organically from local conditions: a passive daylighting strategy that is as much about lifestyle (an oasis for family and social activities) as it is about lighting.
In the 19th and early 20th centuries, as cities industrialized and land values soared, light wells often became just air shafts – but they remained vital. In Paris, Baron Haussmann’s new apartment blocks were built around courtyards or narrow air shafts to ensure that every room had a window. Regulations required minimal light and air, so behind the large stone facades “courtyards allowed light to penetrate the structure… smaller courtyards appeared throughout the block, acting as light wells.” Yet many were cramped and gloomy, functional rather than pleasant. In New York, early tenement buildings crammed families into dark, poorly ventilated apartments. Reformers responded with the Tenement Act of 1879, which mandated air shafts between adjacent buildings to bring some light and air into interior rooms. Builders created “dumbbell” apartment buildings with recesses along the edges, creating thin shafts often only a few meters wide. These shafts were a far cry from the elegant courtyards of earlier eras, but they represented an adaptation of the light well to extreme density. Each apartment building’s waist-like air shaft provided enough indirect daylight and a modicum of ventilation to fulfill the law. Residents leaned over to watch the air or shout their messages into the void. Over time, these chimneys developed a terrible reputation – riddled with trash and fire risks, they showed how a good idea could suffer from inadequate scale. By 1901, New York law banned narrow shafts, requiring larger open courtyards for new buildings. In effect, the law attempted to reposition the light shaft once again as a real courtyard rather than a mere slit for show.
From ancient atriums to utilitarian chimneys, light wells have evolved in form and scale, but have consistently served as a cultural barometer. They have responded to the spatial needs of every society – be it the Roman patron welcoming guests in a sunny atrium or the Manhattan immigrant family trying to catch the breeze in an apartment shaft. In each case, the architecture turned inward to borrow daylight from above when it could not be obtained from the side. Before electric light and modern HVAC, these vertical spaces were the lungs and lamps of buildings. They were born of climate and constraints, but often evolved into treasured architectural features that were centers of beauty, ceremony and social life. This historical arc sets the stage for examining what light wells mean for us today: not only shafts of air and light, but also potential catalysts for prosperity, urban livability and innovative design.
Spatial Psychology: Daylight from Above and Human Wellbeing
Sunlight is not just a technical resource – it profoundly shapes human psychology and physiology. The experience of light flowing from top to bottom, as in a courtyard or atrium, can evoke strong emotional responses. Architects throughout history have intuited this, but today research in environmental psychology and chronobiology illuminates why access to natural light is so critical to the well-being of building occupants. Our bodies are governed by circadian rhythms – the 24-hour biological clock adapts primarily to cycles of light and dark. Exposure to sufficient daylight, especially in the morning and mid-day, triggers hormonal signals (such as the release of serotonin and cortisol) that keep our mood, energy and sleep patterns on track. Conversely, dim and gloomy interiors can lead to lethargy, depression and a distorted sense of time. So a building’s light wells, or lack thereof, can literally affect the occupants’ mental health and perception of time.
Research has repeatedly demonstrated the uplifting effects of daylight on mood and cognitive functioning. For example, a study summarized in Daylight and Architecture states that “adequate amounts of light improve mood and energy levels, while poor lighting contributes to depression and other deficits.” In spaces deep within a building, a well-placed light chimney can provide a column of natural light that helps occupants feel connected to the day outside. This connection is not just poetic – it harmonizes indoor conditions with the human circadian system. Greater exposure to daylight in workplaces is associated with increased alertness and productivity, while access to a sunlit zone in homes can prevent Seasonal Affective Disorder on short winter days. Simply put, vertical daylight penetration can act as a psychological anchor, marking the passage of time through moving sunspots and changing hues of color in a way that electric lights cannot mimic.
Nowhere is the psychological impact of light more evident than in environments of deprivation – prisons, hospitals, windowless institutions. Take prisons: traditionally designed with security rather than comfort in mind, many old prisons allowed minimal daylight, exposing prisoners to constant dimness or harsh artificial light. The consequences for mental health were dire. Modern studies of prison design emphasize that inmates with more exposure to natural light have significantly lower rates of depression and anxiety. In fact, one study found 22% lower rates of depression and anxiety among inmates with windows or sources of daylight, compared to those in nearly lightless cells. Access to a patch of sky can reduce stress, disorientation and even aggression in these environments. Prison architects have responded by treating light as a means of rehabilitation, adding light wells and skylights to dayrooms and even cells. A poignant example is a new prison where a central atrium bathes the inmates’ common space with daylight, which is then “borrowed” into individual cells through interior windows – a strategy that both improves mood and reduces prisoner violations. The message is clear: light wells are not only structural voids, but also emotional conduits. A sunbeam in a high-security prison can literally be a beacon of hope, helping inmates maintain day and night orientation and reminding them of the outside world.
Figure 3: The interior of Tadao Ando’s Church of Light in Ibaraki, Japan. The dramatic cruciform cut in the concrete wall accepts a blade of morning light. This design plays with spiritual psychology – the sharp light/dark contrast evokes hope and faith. It exemplifies how even a simple light opening can profoundly affect mood and perception of space.
Healthcare design has similarly embraced light wells for their therapeutic value. In large hospitals, interior courtyards and atriums bring daylight deep into the wards, helping patients recover faster and stay in sync with the 24-hour day. Patients in windowless ICU rooms have been found to experience higher rates of delirium and disorientation; one study reported that windowless ICU patients were less oriented to time and even hallucinated more than those with window views. To counter “ICU delirium”, many hospitals have installed skylights or light shafts in ICUs and recovery areas so that patients can see some sky or natural light variation throughout the day. The difference can be life-changing: patients exposed to natural light have better sleep patterns, lower stress and shorter hospital stays on average. In schools, too, research shows that daylight improves students’ concentration and mood. When classrooms are organized around open courtyards or have skylights overhead, students not only perform better academically, but also report being more aware of how time passes during the school day (reducing the stagnant, “trapped indoors” feeling). Clearly, a carefully placed light well can act as a compass for the body’s clock. By revealing the movement of the sun – a bright peak at noon, warm low-angle rays in the late afternoon – it reinforces the natural cycles of wakefulness and rest.
Emotionally, light from above has an almost sacred quality in architecture. The play of sunlight in a dimly lit space can enliven and inspire. Many sacred and civic buildings throughout history have used skylights or oculi to create what might be called theatrical daylight effects – think of the Pantheon’s oculus or the way Gothic cathedrals present shafts of colored light. A modern example is Ando’s Church of Light (Figure 3), where the only source of daylight is a cruciform opening carved into the concrete sanctuary wall. In an otherwise dark and minimal chapel, the glowing cross of light becomes a powerful symbol evoking the divine. As worshippers’ eyes adjust, the presence of light dominates the space and directs focus to the altar. This illustrates how light wells and openings shape spiritual and cognitive experience. Even in a non-religious sense, a light well can frame a patch of sky, creating a place of quiet contemplation. In a busy office building, an atrium or courtyard of light with a view of the clouds above can provide a moment of mindfulness – a subtle psychological break while one looks up. In residential design, architects sometimes talk about “bringing the sky in”. A small skylight above a stairwell can create an ever-changing pattern of light and shadow on the walls, acting almost like a gentle clock and calendar as the angle of the sun changes with time and season. Residents often value these daily light shows, realizing that they ground them and enhance the character of their home.
In sum, the spatial psychology of light wells underlines that these features are not merely technical solutions, but profoundly human possibilities. They modulate our mood, behavior and health by connecting us to the rhythms of natural light. A vertical opening can alleviate the claustrophobia of deep-planned buildings, restore circadian balance to people in isolated environments, and even infuse spaces with poetic symbolism. In shaping buildings for wellness and “emotional grounding”, light wells are proving to be indispensable tools – carving a slice of sky within enclosed architecture to nourish the mind and soul. The next question is: How do these benefits play out in crowded and noisy metropolises where space is scarce and privacy is at a premium? Can light wells solve the dilemmas of modern cities as they did in ancient times?
Inward and Outward: Light Wells in Dense Urban Environments
In today’s hyper-dense cities, one might assume that traditional windows on the facade are the only way to get daylight – the facade facing the street is superior. But an intriguing counter-movement in architecture is asking: Can inward-facing light wells be a viable alternative to relying on exterior windows, especially when it comes to tight spaces, noise and privacy concerns? In many cases, the answer is yes. Light wells and courtyards are making a comeback in contemporary urban design as an antidote to some of the pitfalls of high-density living. It allows architects to create what Bjarke Ingels calls a “reimagined courtyard building”, combining the sunlight and openness of a suburban home with the compact footprint of a city block. However, the use of light wells in modern cities requires clever planning to ensure adequate daylight penetration and habitable conditions. Let’s examine a few case studies and comparisons to see how introverted architecture competes with (and complements) traditional fenestration.
Historically, as we have seen, cities like Paris and New York mandated courtyards or air shafts in 19th century apartment buildings to guarantee minimal light and air. These early versions were often grudging compromises – too small to be truly pleasant. According to a famous critique, the air shaft of a New York apartment building quickly became a “chimney of horrors” that collected garbage and carried fires and foul odors because it was a space that no one used. The lesson learned was that for light wells to be successful, they must be of sufficient size and preferably accessible, and not just be redundant voids. Modern building codes and guidelines reflect this: they prescribe larger yard-to-height ratios to ensure that daylight reaches the lowest floors and that space can be conserved. For example, after narrow shafts were banned in New York City in 1901, new “U-shaped” or courtyard apartment buildings provided larger light courtyards opening onto the street or backyard. Paris, with its classic courtyard buildings, resulted in interior courtyards of varying sizes, from generous garden courtyards in luxury buildings to small shafts for servants’ quarters in others. By the mid-20th century, many architects had moved away from light wells, opting instead for thin slab buildings where each room had an exterior window (Le Corbusier’s model of a high-rise in a park). But this often led to other problems: closed air-conditioned facades, lack of shared open space and exposure to street noise and chaos.
Today, architects are rethinking the introverted typology as a way to create calm and private open spaces in the city. A striking example is BIG’s “courtscraper” in Manhattan, VIA 57 West. This 32-story residential building is actually a skyscraper built around a giant courtyard. From the outside, it looks like a pyramid with a sliced top, but inside, the inhabitants have a large, green courtyard that opens up to the sky. The design challenge was to ensure that the courtyard received plenty of daylight despite being surrounded by high walls. BIG solved this by tilting the south side of the building downwards – so that the courtyard opens up to the sun and views of the Hudson River. The result: an interior oasis that is quiet (shielded from street noise by the building mass) but sunny enough to grow grass and trees. As one landscape architect describes it, “the courtyard of VIA 57 West is a park in a pyramid – a space that works in harmony and contrast with the surrounding city.” Standing in this courtyard, you see the sky framed by dramatic facades (like a modern interpretation of the traditional riad – a window to the heavens). Figure 4 shows this view from the courtyard: The effect is striking, like looking up from an urban canyon that is actually your home. Residents enjoy the benefits of a private garden and inward-facing views without sacrificing daylight or a sense of connection to the outside. In fact, the success of the project demonstrates that for residential buildings , courtyard-facing windows are just as desirable as street-facing windows – they may have fewer views, but they offer tranquility and a shared focal point.
Figure 4: Looking up from the central courtyard of VIA 57 West in Manhattan. The building’s faceted form curves around this void, allowing daylight to reach the lower apartments and the courtyard garden. In the dense urban fabric, such introverted designs create a calm, private “inner skyline” while still capturing sunlight.
Privacy is an important driver for inward orientation in many cities, especially where houses are built wall-to-wall. In Tokyo and other dense Japanese cities, architects often design micro-houses that turn their backs on the street and open inwards. Tadao Ando’s Azuma House (1976) in Osaka is a concrete box with a small open courtyard in the center. The house offers a blank face to the street, shielding its inhabitants from noise and neighbors’ eyes, while the inner courtyard provides a single source of natural light and a piece of outdoor space. Many modern Japanese houses follow this logic, incorporating light courtyards or small atriums. One project in Osaka, described as “House with Courtyard in Otori “, uses long perimeter walls with no street windows; instead, all rooms face an interior open-air courtyard. The designers wrapped the exterior in metal cladding, creating a secure and anonymous exterior. But inside, floor-to-ceiling glass around the courtyard offers residents a bright view of a small tree and the sky. “The entire space of this small house is enclosed. The two courtyards are illuminated by slits of light “, while the outside remains windowless. For the residents, this provides a peaceful refuge from the busyness of the city; they sit in the courtyard and enjoy the sunlight while not being exposed to the tight neighborhoods around them. Culturally, this is in line with Japan’s traditional machiya and courtyard houses, but updated with modern architectural language. It’s a strategy eminently suitable for crowded cities around the world: instead of relying on narrow side windows facing the neighbor’s wall a few meters away, why not open a private light well that guarantees your own slice of sky?
Of course, light wells in dense contexts come with challenges. One of these is ensuring that sufficient daylight reaches the base, especially in tall buildings. Architects address this with proportional guidelines (for example, the width of a courtyard should ideally be at least half the building height for good solar penetration). Another tactic is to angle or terrace the building form to widen the exposure to the sky, as at VIA 57 West. Computational simulation helps here – designers now model “3D luxury distributions ” to compare a traditional windowed facade with a courtyard scheme. Often, a central light well can actually distribute light more evenly across a floor plate, whereas perimeter windows give great light near the glass, but quickly drop off towards the interior. Comparative studies in narrow infill spaces have shown that a small courtyard or light shaft can improve daylighting for rooms that would otherwise remain indoors. For example, a study in Paris found that ubiquitous small courtyards (often only 4 by 4 meters in Haussmannian buildings) significantly increased light levels for interior-facing rooms, making the difference between a pitch-black box and a marginally habitable space. In modern buildings, glass and reflective surfaces can maximize the sunlight entering a light well. We also see hybrid approaches: some buildings have “scooped” light wells or atriums with one side open to the street, essentially creating a multi-story recess that acts like a courtyard while drawing direct sunlight from the open side. This has been used in some high-rise buildings in New York to achieve high density while at the same time providing light and air conditions – the building may have a U-shaped or L-shaped notch that creates a long courtyard open at the top and on one side.
Noise reduction is another benefit. City life is noisy – traffic, honking horns, street vendors, endless human activity. Apartments with windows facing only the street have to put up with the noise or keep the windows closed (which leads to dependence on mechanical ventilation). In contrast, windows in the inner courtyard are protected from street noise by the mass of the building. As long as the courtyard is not echoingly closed or filled with its own noisy equipment, it offers a relatively quiet view. At night, residents can open a window overlooking the courtyard and hear birdsong or the sound of a fountain instead of sirens. This is an important reason why classic European apartment blocks and Riads favored interior gardens – they were urban sanctuaries. In the contemporary context, architects see turning inward as a way to achieve what some call “urban calm”. BIG’s VIA 57 West courtyard, for example, not only provides visual relief, but also acoustic relief, acting as a giant buffer against the highway outside. Similarly, many infill housing projects in crowded Asian cities use central light wells to create a quiet core; even if it’s small, it creates a psychological buffer knowing that your window doesn’t face directly onto a busy street or facing neighbors.
As mentioned, privacy is also extremely important. Light wells allow for generous glazing without compromising privacy, as only your immediate neighbors across the courtyard can look in (and the design can stagger the windows to avoid direct gazing). This contrasts with exterior windows, which may require frosted glass or shutters if adjacent to a nearby property or public street. A striking example from Middle Eastern cities: the lower floors of traditional courtyard houses often have no exterior windows – all openings face the courtyard, allowing residents (especially women, according to cultural norms) to be outside and open in their homes without the gaze of strangers. A similar desire is seen in modern condominiums – many people hang heavy curtains on street windows for privacy, ignoring the view and light. A well-designed interior light courtyard can ease this tension: you can enjoy a transparent wall to your little private paradise without feeling exposed.
All this is not to say that light wells are a panacea. Designers must be careful to avoid creating gloomy shafts or unusable dead spaces. The proportion and treatment of the light well is crucial. A courtyard that is too small in relation to the height of the building may only receive an hour of direct sun at noon, leaving the lower floors in constant shadow – a common problem in older apartment buildings. Modern solutions include using mirrors or reflective coatings at the top of shafts to direct sunlight downwards (a strategy we will discuss in the next section on materials). Maintenance is another consideration: courtyards must be accessible and inviting, otherwise they can become garbage pits, as in 19th century apartment buildings. Light wells can really enhance urban living when treated as a social facility and not just as engineering. For example, many new mid-rise condominiums have a central courtyard that doubles as a small garden or patio area for residents. Even if it is only the size of a large atrium, putting a few planters, seating and perhaps a café in the courtyard gives people a reason to take care of and use it, keeping it alive and clean. In this way, the light well becomes not only an atmospheric space, but also a social hub – you might run into neighbors watering plants or drinking coffee under the open sky.
In essence, densely populated urban environments could certainly benefit from revisiting the light well concept. Instead of turning to fully glazed exteriors (which often leads to other problems such as glare, heat gain and lack of privacy), architects are discovering that inward-facing architecture offers a more controlled and community-oriented approach. It challenges the high-rise paradigm by suggesting that windows don’t always have to face the street or the landscape, sometimes the best view is a quiet courtyard with sunlight and a bit of greenery. Inward-facing light wells offer an ethical and spatial opportunity: ethically, they create interior environments that prioritize the peace and privacy of building occupants; spatially, they create overhangs, bridges and gaps that make architecture more complex and rich. As cities continue to grow and land becomes more valuable, we may see the return of the courtyard block and vertical shaft, updated with contemporary knowledge. The key will be to ensure that these light wells are well designed – adequately proportioned, thoughtfully surfaced and integrated into the circulation and life of the building – so that they deliver on their promise of light and air. When they do, the payoff will be huge: quieter homes, happier residents and buildings that breathe in harmony with the city around them.
Surface and Shape: Materials “Painted with Light” in Wells
A light well is not an inert space; its effectiveness is highly dependent on the surfaces that surround it and the geometry it takes on. Designing a good light shaft is in many ways an exercise in “painting with light ” – using reflection, diffusion and strategic shaping to project daylight where it is needed. The materials lining a light shaft can determine whether the lower levels receive a subtle glow or remain gloomy. Likewise, tweaks to the cross-section (such as flaring a light well outward as it rises or chamfering corners) can dramatically increase sky exposure at the bottom. In this section, we’ll explore the technical art of optimizing light wells: how wall cladding choices – matte or glossy, light-colored or dark – and the use of angled planes or light shelves can increase daylight while simultaneously controlling heat and glare. We’ll see how what looks like a simple vertical hole can actually be a fine-tuned tool that utilizes albedo and angles to achieve bright, comfortable interiors.
First, let’s consider material reflection. One of the basic principles of daylight harvesting is that light-colored surfaces reflect more light (white paint reflects ~80% of incoming light, while dark brick can reflect only 20%). In a narrow light well, each wall is essentially both a source and a receiver of light – the sun and sky hit one wall and are reflected in a complex interaction on the other, and so on. Highly reflective surfaces can significantly increase the reach of daylight. Simulation studies confirm this: when researchers modeled the light shaft of a multi-storey dwelling, they found that “increasing the reflectivity of walls has a significant effect on increasing illuminance “, especially in interior rooms on the lower floors. In the study, simply painting the shaft walls a brighter color resulted in much better daylight penetration – the upper floors got a big boost, and even the second floor saw improvement. This makes intuitive sense: a dark, matte surface will absorb most of the light (heating up in the process), while a light, semi-glossy surface will radiate photons back into the shaft. Many traditional designs have used this effectively: Mediterranean courtyards often had whitewashed walls that multiplied sunlight. In Islamic architecture, glazed tiles were used in courtyards – beyond their decorative beauty, their glossy surface reflects light and their typical light colors (turquoise, white, cobalt) ensure that courtyards remain bright. The famous Lion Courtyard of the Alhambra comes to mind: The light well is surrounded by pale plaster and marble surfaces that glow with reflected light, allowing even the areas below the porticoes to receive the reflected illumination.
In modern light wells, architects sometimes go even further and use real mirror-like elements. For example, light shelves or reflectors can be placed at the top of a well to direct additional sunlight downwards. A notable example is the Fulton Center (a subway atrium) in New York City, where an integrated reflective dome directs daylight deep into the station. While this is a high-tech approach, small-scale solutions also exist: some buildings have prismatic glass at the ceiling level of a light atrium to refract light inwards. There are also experimental “light tubes” that coat a shaft with highly reflective material (such as silvered Mylar) to direct sunlight deep inside – essentially acting like a periscope. These devices can increase illumination on lower floors by capturing sunlight from above and transmitting it down in a focused way. However, this needs to be balanced against glare and heat. A too specular (mirror-like) shaft can create blinding spots or uneven light distribution. A matt white surface is often preferred to a mirror because it diffuses light in a diffuse way and provides a softer, more uniform glow in rooms. Glossy surfaces reflect more efficiently but in a directional way – a spot may receive intense beam reflection for a short time, then fall into shadow. A matt surface sacrifices some intensity in exchange for smoothness (like a Lambertian reflector). Some designers use a mix: perhaps glossy ceramic tiles on the lower walls to brighten these areas, but matt finish on the upper walls to avoid harsh reflections into the apartments. There is also interest in reflection spectra – for example, using a slightly blue-white wall paint that reflects cooler light may be more “bright” to the eye than a warm-toned reflection. The science of albedo (reflectivity) becomes an art when applied to an architectural context.
Beyond color and finish, the surface geometry inside light wells can be manipulated to improve performance. One effective strategy is to spread the walls – that is, to make the upper part of the light well wider than the lower part (a bit like a trapezoidal cross-section). This widening significantly increases the portion of the sky visible from below. Traditional courtyard houses sometimes did this naturally: the upper floors were slightly set back around the courtyard, or balconies were placed, effectively widening the light opening as it went up. In modern high-rise buildings, this concept is seen in the form of stepped setbacks or extended atriums. Even a slight angle of the walls of a light shaft, say 10 degrees, can make a big difference in how much direct sun enters the lower levels in the middle of the day. It also allows more reflected (diffuse sky) light to come down, because each wall “sees” more of the sky dome above. Some architects have experimented with directional or funnel-like light wells: imagine a narrow shaft that expands into a cone or prismatic form to capture and concentrate light near the roof. Daylight modeling shows that such funnels can increase the illuminance below by significant proportions. However, practical construction and floor space often restrict how far you can extend a chimney.
Another geometric trick is to use light courtyards or atriums that align with the path of the sun. For example, a narrow north-south oriented light court will receive some sun on the east wall in the morning and some on the west wall in the afternoon. If these walls are reflective, they will reflect light to the opposite side. In contrast, an atrium running east-west may receive full sun on the floor at noon, but its walls may remain more uniformly illuminated with diffuse light. Architects sometimes rotate or shape the atrium to optimize such solar exposure. In climates where overheating is a concern, the shape can deliberately limit direct sun (to avoid turning the light well into a hot chimney) – using more of the ambient skylight. On the other hand, in cold/dark climates, the well can be designed to receive as much sun as possible (even adding thermal mass to the walls to absorb heat).
Materials also affect heat retention. A concern with indoor courts is that they can become heat traps if they are not ventilated – essentially like a greenhouse if covered with glass, or just a stagnant air zone if completely enclosed by high walls. High albedo walls (light colored) can keep the shaft cooler by reducing heat absorption. In some modern designs, phase-change materials or insulating paints have been proposed for light well walls to buffer temperature fluctuations. More common, however, is to choose materials that can withstand the humidity and temperature differences that are often present in light wells (because one side can be heated by the sun while the other side is in shade). Ceramic tile cladding is popular in some light wells (such as bathrooms/kitchens that open into small shafts) because it is durable and its glossy surface helps illuminate the shaft. Some contemporary projects use perforated or textured panels inside atriums to diffuse light in artistic ways – essentially treating the shaft surface as a canvas for light patterns. For example, an architect might cover a light well with perforated curtains that cast speckled shadows, similar to the way a Mashrabiya curtain filters sunlight. While this slightly reduces the total light, it can eliminate glare and create more pleasant ambient lighting.
We should also mention green or reflective roofs at the bottom of shafts. Sometimes designers put a light-colored, reflective surface at the base of the light well (if open to the sky) to act as a light courtyard floor reflector. For example, a white polished courtyard floor or a shallow pool of water can reflect additional light upwards to the lower windows (water largely reflects light when still – and enlivens light when rippling). Ottoman and Islamic gardens often had central fountains or pools, not only to cool off, but also to double the light effect in the courtyard by catching and reflecting the sun. In modern atriums, a highly reflective floor or water feature can similarly brighten the space. However, there is a balance, as too much reflectivity at eye level can cause visual discomfort (e.g. glare on the underside of a pool surface).
To quantify material choices, architects use values called reflectivity (or albedo) coefficients. A few typical values: clean white plaster can have a reflectivity of ~0.8, light concrete perhaps 0.5, red brick ~0.3, vegetation about 0.2 (when dense), black materials <0.1. Metal panels vary – a shiny aluminum can have a specular reflectivity of >0.6 but if it is not matte it can intensify reflections. A smart approach is to use translucent or luminous materials for shaft walls. Imagine lining part of a light well with translucent glass blocks or panels; daylight enters the panel and some of it radiates out the other side, effectively making the wall itself glow and becoming a secondary light source for adjacent spaces. This method was used in several mid-century buildings where bathrooms or stairwells around the perimeter of a courtyard were made of glass block walls facing the courtyard – so that the courtyard received diffused light from these walls. Today, materials such as ETFE foil or polycarbonate can potentially cover a light shaft to similarly increase diffusion.
In terms of form, we also see light shafts being combined with atrium geometries – for example, a long and narrow atrium that can expand at certain levels to create terraces, or a cylindrical light shaft instead of rectangular (a circular shaft has some advantages in reflecting light symmetrically, although it is more difficult to use floor space efficiently). Some research even suggests painting the upper parts of a shaft a slightly different color than the lower parts to improve distribution (since human perception will adjust to brightness gradients). However, an important non-visual consideration is heat: reflective surfaces that help illuminate can also reflect the sun’s heat deeper. If the climate is hot, a little less light is preferable to avoid overheating. This is where surface coatings that reflect visible light but not infrared would be ideal – this is an area of materials science (cold pigments, etc.).
A real-world example that brings many of these ideas together is the One Central Park building in Sydney. The designers have integrated both material and geometric light strategies. In particular, it features a monumental heliostat: a series of motorized mirrors at the top of the building that direct sunlight into the central courtyard and lower towers. The interior of this courtyard and the shaft is lined with greenery (vertical gardens) and light-colored panels, so that the incoming light is softened and diffused around. By actively “painting” the lower areas with reflected sunlight, they have achieved a vibrant interior public space that would otherwise be in shadow behind the tall buildings. At night, the process is reversed – the interior lighting reflects off the same surfaces and the building shines like a beacon through the greenery when viewed from the outside. This dynamic use of materials – reflective glass, plants and mirrors – shows how far the concept of light optimization can go. This is not just a static shaft; it is an interactive light system. As Herzog & de Meuron describe it (they used a similar concept at the Dominus Winery, where gabion walls allow light to pass through pinholes), they see building envelopes as “permeable membranes with varying degrees of transparency”. At the Dominus Winery, the wire basket stone walls act like a thick curtain: during the day, small gaps allow daylight to enter the barrel storage areas, creating a magical speckled effect; at night, interior lights leak out, making the monolithic walls glow from the outside =. Here, the material (basalt stone in a mesh) and the geometry of the cavities turn the entire façade into a giant light modulator, effectively an inverted light well.
Figure 5: The exterior of Herzog & de Meuron’s Dominus Winery (Napa Valley) is built with gabion walls (wire baskets of local stone). The spacing of the stones varies – in some areas tightly packed for opacity, in others loosely packed to allow daylight to filter through. This creates a light effect inside, while the solid stone balances the heat. It exemplifies how material choice (in this case dark stone) and porosity can shape the light quality and thermal performance of an interior.
In a nutshell, designing the “inside” of a light well is as important as designing the “outside” of a building. By manipulating material reflection and surface geometry, architects can effectively shape daylight; brightening dark corners, reducing contrast and even cooling spaces naturally. A well-designed light well usually has light-colored, possibly textured or semi-glossy walls to maximize diffuse reflection. It can expand towards the top or use angled elements to capture more sky. It can use water, mirrors or advanced materials to increase illumination to desired areas. And it will do all this while being careful with energy: reflecting light without undue heat gain or, conversely, using thermal mass to store the sun’s warmth during cold times. These choices turn a passive space into an active light engine. When successful, the results can be stunning – surprisingly daylit lower floors, an almost celestial glow emanating from the depths of a building, and residents who feel the space is alive with natural light. This is indeed a scientific art that blends physics and design intuition. As we strive for sustainable architecture, these passive lighting techniques (highly reflective paints, optimized atrium shapes) are key tools – they allow us to reduce reliance on electric lighting and create more pleasant environments. As will be explored in the next section, light wells can be more than just light providers; with a little holistic thinking, they can also provide fresh air, greenery and even social space, and truly become the living heart of buildings.
Beyond Daylight: Light Wells as Living Systems, Not Just Voids
In an age of climatic urgency and urban densification, architects are redesigning every element of a building to fulfill multiple functions. The light well, often an underutilized space, is transformed into a dynamic, living system that does much more than passively channel light. The question posed is: Can light wells become active architectural elements that integrate natural ventilation, encourage vegetation and provide social space, rather than remaining passive chimneys? The best contemporary designs say yes. By layering functions such as daylight, airflow, greenery, circulation, these vertical spaces can essentially function as the lungs and gardens of buildings. They offer a path to biophilic, climate-responsive architecture, even in very confined spaces. In this chapter, we examine how forward-thinking projects are giving new life to lightwells: from wineries and offices that use chimney-effect ventilation to cool off through open shafts, to residential blocks that turn courtyards into leafy communal terraces, to experiments with water in atriums and interactive facades. The light well thus emerges not as a wasted volume, but as an opportunity to enhance sustainability and well-being.
A fundamental expansion of the role of the light well is as a ventilation shaft. The same vertical form that directs light can also direct air, taking advantage of the stack effect (warm air rises) to provide natural ventilation. This concept goes way back – wind catchers and chimney-like courtyards were common in local desert architecture. For example, traditional Middle Eastern homes often had long courtyards or chimneys with wind scoops that would draw down cool air at night and expel hot air during the day. In modern design, we see this evolving into features such as a “solar chimney”, which is essentially a vertical shaft heated by the sun and creates a draft, sucking in stale air from the building and drawing in fresh air from below. A light well can double as such a chimney if properly ventilated from the top and connected to the rooms by operable high vents. Some architects incorporate temperature-sensitive vents at the top of atriums that open automatically when heat builds up indoors, allowing warm air to escape and triggering airflow. For example, Herzog & de Meuron’s Dominus Winery (Figure 5 above) uses porous gabion walls as both light filters and ventilation pores – the building is kept cool largely by natural airflow moving upward through rock openings and ridge vents, avoiding mechanical cooling in Napa’s hot climate. Similarly, many tropical designs use central courtyards planted with trees so that warm air is discharged upwards through the courtyard (sometimes with the help of fans on the roof) and cooler air is drawn in through the perimeter windows. By converting a light well into a ventilation shaft, a building can breathe without fans – a huge energy saver and often better for the health of the occupants (because natural breezes remove indoor pollutants and provide fresh air).
Another increasingly common addition is vegetation in light wells – essentially creating vertical gardens or green atriums. These serve multiple purposes: plants improve air quality, provide psychological benefits and can help regulate temperature and acoustics. The previously mentioned One Central Park in Sydney is emblematic: its light wells and facade are lined with vertical greenery – 38,000 plants on cables and planter ledges . This “living facade” in the courtyard is not only pleasing to the eye, but also cools the air through evapotranspiration and reduces cooling loads by providing shade to parts of the glass. By treating the light-facing walls as a huge trellis on which vines and shrubs thrive, the designers have effectively transformed the building into an ascending garden. The integration of vegetation into the light well provides biophilic benefits – residents feel closer to nature, birds and butterflies can visit even high floors, and the foliage changes with the seasons, giving the space a dynamic quality. In dense cities where a ground-level garden may be impossible, a courtyard filled with plants becomes an urban oasis. It is literally living architecture. However, greening a light well requires maintenance (watering, pruning) and attention to ensuring that the plants get enough light – sometimes the design will include reflective panels to beam extra sunlight onto the plants, or choose shade-tolerant species for the lower parts. There is also the concept of “sky gardens “, where larger multi-storey light wells contain terraces with trees or large planters at various levels (essentially creating a tiered garden at the height of the building). A good example of this is the Bosco Verticale in Milan (although not exactly a courtyard, the concept of multi-level greenery on a tower can be applied to interior courtyards). Interior gardens humidify and cool the air, acting as natural air conditioners. Research has shown that vegetation in courtyards can significantly lower adjacent air temperatures and reduce the urban heat island effect for that building.
Light wells can also host water features as active elements. A small pool or fountain at the base of an atrium can help with passive cooling (as the water evaporates it cools the air and then rises, increasing the stack effect). Islamic courtyards excelled at this – the combination of a fountain (for evaporative cooling and a pleasant sound) with a light atrium was the hallmark of places like the Alhambra. Modern applications include shallow reflecting pools in office courtyards, which not only cool the incoming air but also reflect extra daylight upwards (the double benefit mentioned earlier). Some sustainable buildings are even exploring using lightwells as graywater treatment bioswales – essentially having planter beds in an atrium that clean water and cool the air at the same time. This combines infrastructure with the light well space.
Beyond climate functions, there is also the aspect of human use. Why not live inside the light well? Increasingly, architects are designing circulation or relaxation spaces into atria and courtyards, making them active social spaces. Instead of being an inaccessible void, a light well can include a grand staircase spiraling upwards, glass elevators or bridges connecting parts of the building – all visually exciting features that draw people into the space. This turns the light well into a kind of covered plaza or vertical street. For example, large commercial atriums often have cafes or seating at their base, encouraging people to live in daylight. When people occupy the light well, they naturally take care of it (no more neglected air shaft syndrome). A great small-scale example is the renovation of a riad in Morocco, where the central courtyard is covered with retractable glass – closed and air-conditioned on hot days, open on mild days – and contains the main living/dining area, so that the formerly open space becomes the most used room in the house. In modern apartment buildings, interior-facing balconies or walkways can surround a multi-level atrium, allowing neighbors to see and greet each other in the space – fostering a sense of community, much like the loggia culture of old European courtyard dwellings or other traditions. Bjarke Ingels talked about this in his courtyard housing projects in Copenhagen: the courtyard becomes a semi-public heart where you can have a communal playground or garden, internalizing social space away from noisy streets. This also works vertically – in a high-rise building, an atrium with staggered common halls on different levels can encourage chance encounters and a sense of shared space that is often missing in high-rise buildings.
Ventilation, vegetation, human use – can a light well really do it all? The best designs try to integrate at least a few of these. One Central Park (Sydney) combines greenery and daylight guiding technology. The Genzyme Center in Cambridge, MA is an office building with a central atrium that performs multiple tasks: reflective mobiles (lightweight sculptural pieces) bring light deep into the floor plate, the stack effect naturally ventilates the building for most of the year, and the atrium space is used as communal relaxation areas on several floors. The result is one of the first large buildings to achieve excellent energy performance with a pleasant indoor environment – employees can literally feel the fresh air and sunlight even in the center of a 12-story building. In Amsterdam’s modern housing, there are examples of narrow but long atriums with glass roofs in winter (acting as solar heaters) and openings in summer (acting as chimneys). Some contain vines and gardens that thrive in the sheltered microclimate of the atrium. Essentially these are climate modifiers: the light well acts as a buffer zone, capturing heat when needed or releasing heat when needed.
Daha önce değindiğimiz Herzog & de Meuron’un Dominus Şaraphanesi (Şekil 5) pasif sistemleri zarif bir şekilde harmanlamasıyla dikkat çekiyor – gabion duvarlar gün boyunca ışığı filtreliyor (bazı alanlarda elektrikli aydınlatmaya gerek kalmıyor) ve geceleri biriken sıcaklığı serbest bırakıyor, tesisin açık uçları ise soğutma için gabion yüzeylerden esintilere izin veriyor. Geleneksel anlamda bir avlu olmasa da (daha çok uzun havalandırmalı bir ahır), bina kabuğunun ve boşlukların çevresel düzenleyiciler olarak düşünülmesini örnekliyor. Bir cepheyi ışık/hava geçirgen bir membrana dönüştürmüşler – bir iç avludaki yüksek katlı bir cephenin de benzer bir şey yaptığını hayal edebiliriz (belki de atriyumun nefes almasını sağlamak için iyi havalarda açılan çalıştırılabilir panellerle).
At a time of climate crisis, when we are trying to reduce air conditioning and bring nature back to cities, the idea of the light well as a “living system ” is incredibly powerful. Instead of seeing it as a lost space that can be rented out, architects and developers can see it as a value-adding element: the lungs (ventilation), the garden (biophilia) and the social core (community space) of the project. This requires an interdisciplinary approach – involving mechanical engineers to make the airflow work, landscape designers for the plants, perhaps smart controls for operable vents or shades at the top of the well. But the payoff is a building in harmony with natural forces. Chimney ventilation can significantly reduce cooling energy. Indoor plants can reduce stress and improve indoor air quality by absorbing VOCs. Providing building occupants with an attractive, daylit common space increases satisfaction and well-being (research shows that people strongly prefer to have access to such atrium spaces in offices and residences). There is also an “ethical” dimension: Introverted architecture is an ethical opportunity because it creates a collective space within the building – a semi-private space shared by the building’s inhabitants, rather than fully privatized individual balconies or public parks that may be far away. In dense urban housing, an interior courtyard can be a safe playground for children away from traffic, or a place for the elderly to sit in the sunshine without leaving the building – an important social benefit.
It is worth noting that these multifunctional light wells also reflect historical precedents. Ancient Roman atriums collected rainwater (a functional integration of water supply and light reception). Many Islamic courtyards had fruit trees and fountains – providing food, cooling and beauty all in one. So in a sense, after a period of separation of functions (where HVAC did ventilation, artificial lights did lighting, and courtyards fell out of favor) we are returning to the holistic use of courtyards. The difference now is that we have the technology to fine-tune them and the urgency to make buildings more sustainable.
Figure 6: The living green walls of One Central Park in Sydney. The building’s interior courtyards and facades are covered with thousands of plants on balconies and cables, creating a vertical garden that cools the air and provides a biophilic environment for the building’s occupants. At the top of the tower (not visible here) a motorized heliostat projects additional sunlight into the courtyards. This project shows a light well transforming into a multifunctional ecosystem providing daylight, greenery, fresh air and aesthetic pleasure.
As shown in Figure 6, One Central Park’s combination of green and technology symbolizes this new paradigm. Mounted on a console, the heliostat – an active sun-tracking mirror system – directs sunlight into areas that would otherwise be shaded by the towers. In effect, it turns the light well into a giant light diffuser; after bouncing off the mirrors, the light streams through a glass skylight into the retail atrium and lower courtyard, supporting plant life and illuminating the space. At night, the same cantilevered structure features an art installation that reflects artificial light in patterns and animates the sky above. The light well is thus part of an integrated 24-hour cycle of building systems – daylight during the day, artistic illumination at night, always attracting the attention of building occupants and passers-by.
The takeaway here is that a light well no longer needs to be a static, single-purpose space. With creative design, it can be the sustainable backbone of a building, providing passive cooling, natural light, air circulation and contact with nature in a single package. As cities struggle to make high-density living more humane and environmentally friendly, the humble light well is emerging as a powerful tool. It invites architects not just to cut holes in roofs, but to transform these gaps into active spaces that breathe and grow. The light well of the future could house solar panels around the top that also act as a canopy, or it could have responsive membranes that open and close for climate control. It could be a “climate chimney ” on hot days and a cozy courtyard on cool days. In essence, it becomes a living nucleus for the building organism – like the trunk of a tree that channels nutrients.
As a result, the evolution of light wells – from ancient courtyards to modern shafts – has come full circle, in principle if not in form. We rediscover that solutions to many contemporary challenges are already present in vernacular architecture, waiting to be reinterpreted. Light wells have always been cultural responses to climate and spatial needs. Now, with advanced know-how, we are enriching them as responsive, green, human-centered spaces. These spaces remind us that architecture is not just about enclosing space, but also about opening it up to natural forces in beneficial ways. A ray of light falling into a courtyard can lift the human spirit; a cool draft of air rising from a shaft can reduce a building’s carbon footprint. Once simple and static, these vertical voids are now dynamic drivers of design innovation, from the sublime ethereal light of Ando’s church to the lush hanging gardens of Sydney’s skyscrapers. As glass curtain walls slowly surrender to more climate-sensitive designs, it may be the rediscovered and reactivated light well that will take center stage in shaping the future of healthy and sustainable architecture.
