Energy in the Cities - Global Warming - Climate Change - Birds Migration

Due to global warming, bird migrate two days earlier each decade

Similar to light pollution, a study suggests that rising temperatures are causing birds to migrate a little earlier each spring. Due to global warming that the journey home is shifting forward by a little less than two days each decade. That doesn’t sound like much. But if we calculate over 5 decade multiply by hundreds of migrating species all over the country. In other words, climate change is causing a noticeable, gradual, shift in one of nature’s grandest natural phenomena.

Due to global warming food availability is mismatch

An earlier bird migration due to global warming does not synch with the growth of new plants or the availability of food. Global Warming, Climate change might be affecting the timing of spring vegetation blooms or the abundance of insects and other food sources—factors that can strongly affect the survival of migrating birds. Besides food availability, global warming is like to impact bird migration such as increased storm frequency, lowered water tables, higher drought frequency, sea-level rise, and habitat shifts. 

Generally speaking, short and middle-distance migrating birds can adapt to climate changes more easily, whereas long-distance migrants are at a disadvantage. Their migration rhythm is usually more fixed and they struggle with readjustment to changing temperatures. Because of this rigidness, they suffer more from the impacts of climate change than other birds.

What should we do?

Climate change is in progress, and it is clear that it is affecting our environment, by adding to the disarrangement of ecological balances. It is not only in the interest of migratory birds but also in our own interest to protect all species on the planet earth against the impact of climate change.

Cities consume three-quarters of the world's energy and are responsible for 80% of its greenhouse gas emissions. First, reducing energy use in buildings such as HVAC and Lighting energy while promoting clean energy can slow global warming. Second, select the building location can lower building occupant transportation energy use. Finally use local building materials can decrease transportation and manufacturing energy uses.

ALTA Integra is a multi-discipline building physics engineer designer such as acoustics sound, lights, thermal, air quality, and etc. Research agreed that the built environment is affecting the sensor, emotion, behavior, and biology of humans and other living objects. Our mission is to create a greener, healthier, beauty and comfort to lives in.   

#wildlife #birds #globalwarming #climatechange #architecture #greenbuilding #buildingphysics #integratingknowledge #energy #city

Lights of the City - Beautify the City or Light Pollutant threats Living Creatures

“How do birds know when to fly to the sun?
Who tells them the seasons?
How do we, humans know when it is time to move on?
As with the migrant birds, so surely with us, there is a voice within if only we would listen to it, that tells us certainly when to go forth into the unknown.”

— Elisabeth Kubler-Ross (Swiss-American psychiatrist and author)

Besides help visual sensory, lights affect birds’ behavior and biology. Light pollution has been shown to change migration and nesting time, disorient migrating birds, disrupt hormones and sleep in birds and other wildlife, and contribute to declines in insects that birds eat.

As temperatures warm and plants bloom, eager birds await the arrival of summer residents like warblers, tanagers, vireos, and grosbeaks, the sights of light are a sure sign of spring of migrating birds. Light pollution in a city causes false signs of spring of mitigating birds, nesting, and mating time. This behavior change also affecting bird reproduction quantity and quality.

Excessive Artificial Light at Night (ALAN) can also disorient birds during migration, bright lights at night on large buildings attract birds in the same way that bright porch lights attract moths. Which can result in fatal collisions. A recent study estimates that between 100 million and one billion birds are killed in the United States each year as a result of collisions with buildings. Given that most songbirds migrate at night, it’s no surprise that light pollution is a significant contributor to the harm of these birds.

Same with humans and other living creatures, light pollution will disrupt the circadian rhythm that causes disrupt biological hormones that control sleep and awake condition. Disorientation of sleep and awake condition can cause serious health problems and that lead to death.

Last but not least, light pollution contributes to declining insects that birds eat. Over a seven-year period, the bird showed a real change in their reproduction when comparing behavior near streetlights with those without lights. The change was that, on average, females near lights laid their eggs 1.5 days earlier than those in the dark, this may lead to a mismatch between the timings of peak food demand from their baby chicks and the peak timing of food that is available.

ALTA Integra is a multi-discipline building physics engineer designers such as acoustics sound, lights, thermal, air quality, and etc. Research agreed that built environment is affecting sensor, emotion, behavior and biological of human and other living object. Our mission is to create a greener, healthier, beauty and comfort to live for.  

#light #lightingdesigner #lightingdesign #facadelighting #birds #nature #health #mentalhealth #lightpollution #cityscape

Sounds of the City - Between Noise Pollution and Beautiful Soundscape?

“Have you ever wonder, where have all the birds gone? ”

In Jakarta city nowadays we hardly see birds nesting, flying, or looking for food. Some research says that nature soundscape such as the sound of running water, or birds singing will improve mental health. However, due to the increasing noise pollution, the sound of birds became the sound of machinery.

Loud sound can have a serious impact on human health as well as on ecosystems. The effects of noise pollution on birds have been a key subject of study for scientists and conservationists over the last decade. Researchers suggest that noise pollution affects their behavior, fitness, breeding, and growth, and often leads to chronic stress.

Scientists say that constant noise may form an acoustic blanket muffling the audio cues birds rely on to detect predators, competitors, and their species. Noise pollution delayed nesting for birds whose songs are at a lower frequency and thus more difficult to hear through low-frequency human noise. When considering noise pollution, results showed that birds living in forested environments tend to be more sensitive to noise than birds in open environments. 

You may have noticed that many birds around us sing at different pitches or volumes in response to noise. One well-known example is Robins, which sing at quieter times of the day or night. This could be seen as an adaptation, but the problem is that this change can disrupt mating and affect breeding success in such birds.

For birds, hearing is second in importance only to vision for monitoring the world around them. Avian hearing is most sensitive to sounds from about 1 to 4 kHz, although they can hear higher and lower frequencies. No species of bird has shown sensitivity to ultrasonic frequencies (>20 kHz). Sensitivity to frequencies below 20 Hz (infrasound) has not received much attention; however, pigeons and a few other species have shown behavioral and physiological responses to these low frequencies. In general, frequency discrimination in birds is only about one-half or one-third as good it is for humans within the 1 - 4 kHz range.

A problem that birds suffer that is similar to humans is damage to the auditory receptors (hair cells) from loud noises. The sound intensity that produces damage and the amount of damage produced differ depending on the species. Birds residing in the active areas of airports might be constantly subjected to sound pressure levels that damage their hearing. Thus, to effectively disperse birds using sound, auditory alerts must be at frequencies that can be detected by the damaged auditory receptors. Although some if not all species of birds have the ability to repair damaged hair cells, continued exposure to loud noises would prevent recovery of their hearing.

ALTA Integra is a multi-discipline building physics engineer designer such as acoustics sound, lights, thermal, air quality, and etc. Research agreed that the built environment is affecting the sensor, emotion, behavior, and biology of humans and other living objects. Our mission is to create a greener, healthier, beauty and comfort to lives in.  

#sounddesign #sounddesigner #soundscape #acoustics #birds #nature #health #mentalhealth #noisepollution #cityscape

Psychoacoustic survey guitar violin live recording

Psychoacoustics survey of three live recording microphone location:

1. Near microphone

2. Near-Far microphone

3. Far microphone

Question:

1. Which recording has the most blending sound between guitar and violin?

2. Which recording has the most tonality balance between low and high frequency?

3. Which recording is the nicest sound attack and decay?

Please leave your answer on HerwinGunawanWork YouTube Channel

Thank you for participating.

#music #sound #sounddesign #design #psychoanalysis #humancentric #acoustics

From Google Map to Architectural Facade Design

How do we work with Architect and Facade Engineering to design indoor healthy level noise environments surrounded by the noisy streets?

Google Map View with point of measurement for data verification

Create 3D modeling of the project with DataKustik CadnaA acoustics software

Noise Mapping Prediction Output from DataKustik CadnaA

Side view of Noise Prediction at the Building Facade (Design A)

Side view of Noise Prediction at the Building Facade (Design B)

With the scientific methodology of Acoustic Prediction, the Owner, Architects, and Facade Engineer can see the noise impact of each design and can make a confident decision to optimizing the synergy between building aesthetic, outdoor view, daylight, sound, and thermal insulation.

We, ALTA Integra strongly believe that our life quality is affected by building physics environments such as Sound, Light, Air, Temperature, and other physics elements. That’s why we do what we do and we are happy to invite you to share this belief.

#architecture #facade #environmenthealt #buildingphysics #noise #traffic #urban #city #jakarta

The evolution of Architecture’s Beauty and Science philosophy is by self-learning from its own history

Hegel's (1826) theory that architecture is the Absolute Spirit expresses cognitive content as an aspect of organizing the natural environment. As with Architecture History in general, Hegel offers a progressive account of architectural history, wherein successive stages the Symbolic, the Classical, and the Romantic periods bring increasing freedom among architectural objects from symbolism and purpose and enhanced expression of the Absolute Spirit.

Symbolic Architecture is where the shape of the architecture is trying to free itself from its nature, as Aristotle (384 BC) said that architecture form is pursuing the holiest picture of biological explorations as the “total form” of the animal. The paradigm example of Symbolic Architecture is Sphinx which might symbolize the holiest form of animal and the Pyramid that functions more as a symbol of the everlasting home for their king which regards as a son of God.

Sphinx and Pyramid is the paradigm example of Symbolic Architecture

Classical Architecture is a harmonious shape between form and function, the architecture is made from wood, stone, and marble. The architecture design and build with a purpose. The purpose of the temple mainly concentrated on the naos, the "dwelling" of the cult statue. A famous example of Classical Architecture is the Greek Temple. The elaboration of the temple's external aspects served to stress the dignity of the naos. Similar to the Pyramid the interior part of the architecture is remark as a sacred place.

An image of Greek temple made from stone and mud

Romantic Architecture philosophy is born after Christianity, so the interior function as a collective place for people to celebrate or worship. The architecture concept of beauty is beyond functionality with decorative ornament and stained glasses due to the development of material process technology and architecture science. This is true even of the Gothic, which Hegel takes as an ultimate (if qualified) success in the history of architecture for its metaphorical communication of spirit.

Along with the material technology and architecture science - Gothic Architecture is the enhanced expression of the Absolute Spirit

After Hegel's theory about Romantic Architecture which is the time when he lived, below are some thoughts from modern Architecture philosophers.

Merleau-Ponty (1945) that our existence in the world is best understood through ways it is shaped by the bodily experience of our surroundings. That bodily experience is relative to what appears in our visual field, to our tactile and kinesthetic engagement (hence to our position and motion), and to who we are as individuals and group members.

Graham (2012), the central problem of architectural aesthetics is to account for architectural meaning and value while embracing a synthesis of artistic value and utility (“engineering”) value.

J. Robinson (2012) offers an architectural application: our experience of the built environment shapes our appreciation of, and abilities to negotiate our surroundings.

ALTA Integra believes that smart and strategic integration of Architectural Building Physics knowledge such as Acoustic, Lighting, Thermal, Air Quality, and other disciplines into the built environment will make a big impact in our future history.

Modern architecture is to find the optimal blend of purpose, art and engineering

#philosophy #art #history #human #architecture #interior #science #engineering

Illumination Environment and Human Biological Response

Gereja Katedral Jakarta Plaza Sumpah Pemuda Lighting Condition

Several studiesanalyzed how humans respond to a space environment and noted that people can react to space in a cognitive, emotional, and biological way. Besides cognitive and emotional responses under certain lighting conditions, we have interesting questions about the short-term biological effects of lighting on people.

If we look at the two pictures below, will people respond differently?

How people will behave in this lighting condition?

If they walking passing by, which route do they take?

How fast are they walking speed?

Will people behave differently in this lighting condition compare to the above light condition?

Will they take different route?

Will they walk faster or slower?

ALTA Integra believes strategic Integration of Architectural Building Physics knowledge such as Acoustic, Lighting, Thermal, Air Quality, and other disciplines in the built environment will make a big impact. So let’s join our mission to share this belief and passion to make our world a better place.

#lighting #lightingdesign #human #behavior #biology #psychology #architecture #interior #space

Speech Intelligibility in the multi-media conference room

For superior audio quality in multimedia conference system, it’s important

to calculate human voice, microphone, and loudspeaker

technical factors before installation

Multimedia conferences in Boardrooms can bring your meetings to life – integrating audience - engaging capabilities such as voice, video, graphics, and data into your presentations. But the design focus should be on your message speech intelligibility, not on the technology.

In order to design multi-media conference audiovisual technology integration that can deliver your message clearly, ALTA Integra always calculates the  following factors:

Human Voices Factors: speech level at normal to raise vocal effort (reference 60 dB to 66 dB at 1 meter), sound directivity, and distance to the microphone. Microphone Factors: Microphone sensitivity, directivity, and position. Loudspeakers Factors: loudspeaker level, directivity, distance to human ear and microphone to avoid audio feedback. Last but not least Acoustics Environment factors such as ambient noise and reverberation time.  

Integrating Architectural Building Physics knowledge such as Acoustic, Lighting, Thermal, Air Quality, and other disciplines play important role in making a better space for human-being. So let’s join our mission to share this belief and passion to make our world a better place.

#interiordesign #acoustics #audiovisual #videoconference #multimedia #teleconference

Night Sky Biomimicry Design in Home Theater

biomimicry night sky in home theater design side view

Biomimicry design is a concept used within the building architecture to increase occupant connectivity to the natural environment through the use of direct nature, artificial technology to create nature ambient, in space and place situation.

Biophilia term has been used since by many scientists, and philosophers overall being adapted to several different areas of study. Some notable mentions of biophilia include Edward O. Wilson’s book Biophilia (1984) where he took a biologist’s approach and first coined the “Biophilia hypothesis” and popularized the notion. Wilson defined biophilia as “the innate tendency to focus on life and lifelike processes”, claiming a link with nature is not only physiological but has a genetic basis.

In this Home Theater project, ALTA Integra’s multi-discipline design team recreate a family entertainment ambient as if they sit under a night sky. Now the happy family can enjoy gaming, karaoke, or movie streaming in audiovisual quality in a good acoustic, lighting, and interior design.

3D preview of home theater design with karaoke and gaming feature

Integrating Architectural Building Physics knowledge such as Acoustic, Lighting, Thermal, Air Quality, and other disciplines play important role in making a better space for human-being. So let’s join our mission to share this belief and passion to make our world a better place.

#interiordesign #acoustics #lightingdesign #hometheater #videogames #karaoke #movie #biophilia #biophilicdesign

seamless interior acoustic and lighting design in this home theater design

Direct vs. Direct-Indirect Lighting: What the Evidence Actually Says About Office Performance

A 40-Year Literature Review on Visual Comfort, Wellbeing, and Workplace Performance

Abstract

Over the past four decades, research in visual ergonomics, lighting engineering, and human-centered workplace design has consistently demonstrated that the quality of office lighting depends on more than horizontal illuminance alone. This review synthesizes evidence from academic research, post-occupancy evaluations, and leading lighting industry organizations to compare direct-only and direct–indirect lighting strategies in modern office environments.

Across laboratory experiments, field studies, and industry investigations, occupants consistently rated direct–indirect lighting as more comfortable, brighter, more spacious, and more visually appealing than direct-only lighting when task illuminance was held constant. These improvements are primarily attributed to enhanced luminance distribution, brighter ceilings and walls, lower luminance contrast, reduced discomfort glare, and increased vertical and cylindrical illuminance. However, objective measures of cognitive performance—including attention, memory, and task accuracy—generally showed little or no consistent improvement when horizontal illuminance and spectral characteristics remained unchanged, indicating that the principal benefits arise through perceptual and psychological mechanisms rather than enhanced visual acuity alone.

Academic findings are further reinforced by applied research and design philosophies from leading lighting organizations—including DIAL, ERCO, Zumtobel, Fagerhult, Targetti, TRILUX, Signify, Panasonic, and Bartenbach—which collectively emphasize luminance distribution, visual comfort, spatial brightness, vertical illumination, glare control, and daylight integration as the primary determinants of lighting quality. Rather than relying on a single lighting strategy, contemporary practice increasingly advocates layered lighting solutions that combine direct, indirect, wall-washing, and accent lighting to support both architectural perception and occupant well-being.

Overall, the evidence suggests a fundamental paradigm shift from illuminance-based lighting design toward perception-oriented, human-centered lighting. Modern office lighting should therefore be evaluated not only by horizontal illuminance, but also by the quality of luminance distribution, visual adaptation, and the overall human experience of the built environment.

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Introduction

Modern offices have never been brighter. Yet complaints of glare, eye strain, headaches, and visual fatigue continue to increase. If today's workplaces already satisfy recommended illuminance standards, why do so many employees still find their lighting uncomfortable?

Over the past three decades, numerous field investigations have reported increasing levels of visual discomfort, eye fatigue, headaches, musculoskeletal symptoms, psychological stress, and dissatisfaction with lighting conditions among computer-based office workers. These findings have prompted lighting researchers and practitioners to reconsider conventional office lighting strategies that were originally developed around horizontal illuminance requirements rather than human visual perception.

Unlike traditional offices, contemporary workspaces require employees to spend prolonged periods viewing self-luminous displays, making visual comfort a critical factor influencing both occupational health and workplace performance.

In response to these challenges, substantial research has been devoted to improving lighting quality in computerized workplaces. Rather than relying solely on direct downward illumination, many researchers and lighting manufacturers have advocated the use of direct–indirect lighting systems, which distribute luminous flux toward both the workplane and the ceiling.

This approach creates a more balanced luminance environment by increasing ceiling and wall brightness, reducing luminance contrast, improving vertical illuminance, and minimizing discomfort glare. Numerous experimental and field studies have consistently shown that occupants generally perceive direct–indirect lighting environments as more comfortable, brighter, more spacious, and visually pleasant than conventional direct-only lighting systems, even when horizontal desk illuminance remains identical.

These findings have also been reinforced by leading architectural lighting organizations—including ERCO, Zumtobel, Fagerhult, TRILUX, Targetti, Signify (Philips Lighting), and Bartenbach LichtLabor—which increasingly advocate perception-oriented lighting design. Rather than focusing exclusively on workplane illuminance, these organizations emphasize luminance distribution, vertical illuminance, wall and ceiling brightness, glare control, daylight integration, and human-centered lighting principles as fundamental determinants of workplace quality and occupant wellbeing.

Despite the growing consensus that balanced direct–indirect lighting generally outperforms direct-only lighting in terms of visual comfort and occupant satisfaction, an important scientific question remains unresolved. Most previous studies have primarily compared extreme lighting configurations, such as 100% direct lighting versus mixed direct–indirect systems, without systematically investigating how different direct-to-indirect light ratios influence human responses. Consequently, relatively little guidance exists regarding the optimal proportion of uplight and downlight that simultaneously maximizes visual comfort, perceived brightness, spatial quality, cognitive performance, and psychological wellbeing.

Moreover, existing evidence suggests that the relationship between direct–indirect light distribution and human performance is more nuanced than initially assumed. While improvements in visual comfort, perceived spaciousness, and occupant satisfaction are consistently reported, findings regarding objective cognitive performance—including attention, memory, and task efficiency—remain mixed. This suggests that lighting distribution alone may not fully explain workplace performance and that other factors, such as vertical illuminance, circadian-effective lighting, daylight availability, luminance hierarchy, and visual adaptation, may play equally important roles.

Therefore, the next logical question is no longer whether direct–indirect lighting is preferable to direct lighting, but rather What is the optimal ratio between direct-indirect lighting that best supports occupant visual comfort, cognitive performance, and overall wellbeing in modern computer-based work environments?

Addressing this question is increasingly important as workplace lighting evolves beyond conventional illuminance-based standards toward Human-Centered Building Performance, where lighting quality is evaluated not only by its ability to provide sufficient light for visual tasks, but also by its influence on perception, physiology, psychology, and human experience. This review therefore synthesizes evidence from peer-reviewed academic research together with leading industry research from ERCO, Zumtobel, Fagerhult, TRILUX, Targetti, Signify, and Bartenbach LichtLabor to examine how varying direct–indirect lighting distributions affect occupant comfort, cognition, wellbeing, and workplace performance, while identifying current knowledge gaps and future research directions.

Across these studies, a consistent pattern emerges: Improved subjective experience with mixed lighting, but minimal direct effect on simple cognitive test outcomes. Workers report “the room feels brighter” or “more open” under higher indirect component, even when meter readings at the desk are unchanged.

Representative Finding: In Lu et al. (2019), participants rated settings with more uplight as having “milder shadows of objects … more eye’s comfort, more feelings of spaciousness and pleasure”.

On the other hand, purely direct systems often induce complaints of glare or visual fatigue. For example, Boyce et al. (2006) noted that adding uplight (or personal task control) “tended to maintain motivation and vigilance” during the day, whereas direct-only conditions risked reflections on screens and uneven brightness. This matches anecdotal POEs where staff describe direct-only offices as “gloomy” or “cave-like” when ceilings are dark.

Research Methodology and Metrics

• Illuminance/Luminance: Horizontal workplane lux, vertical eye-level lux, surface luminance (cd/m²).

• Brightness Perception: Semantic ratings (e.g. “bright–dim” scales), paired comparisons.

• Visual Comfort: Glare indices (UGR/VCP), self-reported eye strain/glare, adaptation ease.

• Wellbeing: Questionnaires (mood, stress, satisfaction).

• Performance: Standardized tasks (typing, memory, vigilance, math).

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Academic Research

Seminal Field Studies (Hedge 1989, 1995)

Alan Hedge’s classic Cornell studies in the late 1980s and 1990s are foundational. In a large virtually-windowless office, Hedge et al. (1989, 96 workers) compared parabolic downlighting (100% direct) to ceiling-suspended lensed-indirect fixtures (100% uplight). Both systems provided similar desk illuminance, but the indirect system scored far higher on comfort scales. Workers under the lensed-indirect lights reported “less glare on the computer screen,” “fewer eye problems (tired eyes, trouble focusing),” and “better productivity”. Overall lighting satisfaction was significantly higher with indirect uplights, even though measured lux levels were equivalent.

In a larger pre/post study (Hedge et al., Ergonomics 1995), a parabolic-downlit office was retrofitted with ceiling uplights. Again, employees preferred the indirect scheme. Questionnaire responses showed the indirect lighting was rated more favorably on all subjective scales. Notably, screen glare complaints dropped dramatically workers reported fewer and less frequent vision problems under the uplights. Lighting satisfaction scores were significantly higher, and self-reported productivity was less hindered under the indirect system. Crucially, these effects occurred without any change in measured illuminance, confirming that distribution – not lux – drove the differences. Approximately two-thirds of workers ultimately preferred the indirect lighting.

Key testimonial findings

Across these studies, workers spontaneously noted that the indirect-lit office was more appropriate for computer work, with far less bothersome glare. Such comments included “less difficulty focusing,” “fewer tired eyes,” and “lighting is more comfortable for screen tasks.” By contrast, purely direct environments elicited remarks like “too bright overhead causing glare,” “dark ceiling makes it feel like a cave,” or simply “harsh” and “stressful” (Hedge 1989, 1995; Houser 2002). In sum, mixed direct–indirect lighting yielded higher satisfaction and fewer visual complaints in real offices.

Laboratory and Simulated Office Experiments

Multiple controlled studies have systematically varied the direct-indirect ratio while keeping desk illuminance constant. These reveal how uplight fraction and lumen distribution affect perception.

Houser et al. (2002, USA)

In a 12.7×7.2 m mock-up, subjects viewed 11 lighting scenes (pendant fluorescents) with 0–100% uplight. They rated each scene in paired comparisons and rating scales. Key findings overall brightness perception came from walls/ceiling, not desk; spaces looked more spacious with higher uplight; and lighting conditions with ≥60% of illuminance as uplight (i.e. down:up ≈40:60 or less) were strongly preferred. In other words, once you reach ~60% uplight, subjects rated ceilings bright and environments more open.

Houser & Tiller (2004, Germany)

The study further demonstrated that occupants generally preferred lighting environments incorporating an indirect lighting component, reinforcing the importance of balanced luminance distribution.

de Vries et al. (2021, Netherlands)

An open-plan office experiment systematically varied the direct–indirect lighting ratio and ceiling luminance uniformity while maintaining constant desk illuminance. Consistent with Houser et al. (2002), increasing the indirect lighting component and improving ceiling uniformity significantly enhanced perceived brightness, attractiveness, and visual comfort. Interestingly, cluster analysis identified two groups of participants: one consistently preferred brighter, high-indirect environments, whereas another was less sensitive to luminousness and slightly favored dimmer atmospheres. Overall, lighting systems incorporating approximately 35–65% indirect lighting achieved the highest levels of occupant satisfaction.

Shin et al. (2014, Korea)

A laboratory EEG study involving 28 young adults compared direct-only lighting (700 lx downlight) with a balanced direct–indirect system (400 lx downlight + 300 lx uplight), both at 4000 K. Following four-minute exposures, participants rated the lighting environment while frontal EEG activity was recorded. The mixed lighting condition was perceived as significantly more pleasant and emotionally comfortable, accompanied by increased frontal theta activity associated with positive affective responses. Because no cognitive performance tasks were included, the study primarily demonstrates the emotional and perceptual benefits of balanced luminance distribution rather than objective productivity gains.

Khanh & Bix (2026, Germany)

Their laboratory and field investigations demonstrated that perceived brightness, spatial quality, and occupant preference correlated strongly with ceiling and wall luminance rather than horizontal illuminance alone. Among the lighting configurations evaluated, participants consistently preferred balanced direct–indirect distributions, reinforcing earlier findings reported by Houser et al. (2002) and de Vries et al. (2021).

Summary of lab results

In controlled settings, observers consistently rated balanced lighting higher. Conditions with significant uplight (around 50–60%) were deemed brighter and more spacious. Reported affect was also more positive under mixed lighting. These studies did not show any cognitive benefits or deficits – none measured task performance – but they firmly establish the perceptual preferences that field studies reported anecdotally.

Field Simulation and Cognitive Performance

Boyce et al. (2006) conducted extensive office simulations at PNNL, contrasting direct vs mixed lighting under realistic conditions. In Experiment 1 they tested four setups: (a) direct-only recessed parabolic ceiling lights, (b) direct–indirect pendants (fixed), (c) direct–indirect with controllable desk lamp, and (d) individual direct–indirect fixtures with adjustable uplight. In Experiment 2 they compared prismatic downlights vs suspended direct–indirect (both fixed, no control).

Comfort/Satisfaction

All participants rated the direct–indirect environments as more comfortable than direct-only. Furthermore, giving users local control (desk lamp or adjustable uplight) further increased comfort and satisfaction.

Performance

Critically, the researchers found no simple main effects on task performance. Across a battery of vision-based tasks (visual acuity, vigilance, etc.), neither full direct nor direct–indirect lighting produced statistically better results. As Boyce et al. state, “expected changes in performance with practice and fatigue were found, but no main effects of lighting quality” on any task. The only subtle effect was that having control (which often coincided with mixed lighting) helped maintain alertness/motivation over time.

Interpretation

These field experiments reinforce the pattern: direct–indirect systems enhance comfort, but do not significantly change objective performance. The addition of a desk lamp also mimics personalized lighting control, another known comfort booster (though that goes beyond our focus).

Fostervold & Nersveen (2008, Norway) similarly found minimal cognitive differences with varying uplight fractions. In a 4×3 mixed-design office study, they tested four ceiling lighting schemes ranging from mostly direct to mostly indirect (ratio inversely varied), removing any glare sources. They measured subjective health symptoms, well-being, and cognitive tasks. The only significant finding was that pure direct light slightly reduced reported job stress. Beyond that, the direct-indirect proportion had no significant effect on any outcome measure. In other words, cognitive test scores and well-being ratings were essentially unchanged by lighting mix once glare was controlled.

Summary of cognitive data

Across these controlled trials, adding uplight did not reliably improve task accuracy or speed. When tight controls are in place (and especially when glare is eliminated), direct-only vs mixed lighting yield similar objective performance. The clear benefit of mixed lighting lies in perceived comfort and satisfaction, not in raw visual performance.

Academic Research Consensus

• Mixed direct–indirect lighting consistently improves perceived comfort.

• Objective cognitive improvements remain limited when illuminance and spectrum are controlled.

• The dominant mechanism appears to be perceptual rather than visual acuity.

Synthesis of Academic Research

Academic research answers a fundamental question: Why do people consistently prefer direct–indirect lighting over direct-only lighting?

Collectively, academic research demonstrates that the principal benefit of direct–indirect lighting lies in enhancing the quality of the luminous environment rather than simply increasing task illuminance.

Across field studies, laboratory experiments, and post-occupancy evaluations, occupants consistently preferred environments with balanced uplight because they produced brighter ceilings, more uniform luminance distribution, lower luminance contrast, reduced discomfort glare, and greater perceived spaciousness.

However, when horizontal illuminance and spectral characteristics were held constant, objective cognitive performance showed little or no consistent improvement. These findings indicate that the primary advantages of direct–indirect lighting arise from improved luminance distribution, visual adaptation, and perceptual quality, rather than from enhanced visual acuity or basic cognitive performance.

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Lighting Industry Insight

DIAL GmbH Lighting Research

Between 2000 and 2003, DIAL GmbH conducted a controlled office study involving 44 participants to investigate how seven lighting concepts: direct lighting, indirect lighting, direct–indirect lighting, wall washing, direct-wall washing, vertical accent lighting, and horizontal accent lighting — influence visual performance, room perception, and occupant well-being. Participants performed both paper-based and computer-based reading tasks while evaluating perceived brightness, attractiveness, activation, and overall well-being under each lighting condition.

Consistent with findings reported by Houser, Boyce, and ERCO, DIAL observed that variations in lighting distribution had a much greater influence on occupants' perception of the space than on objective reading performance. Lighting concepts incorporating indirect illumination and illuminated vertical surfaces consistently produced brighter, more attractive, and more comfortable environments than conventional direct-only lighting. Conversely, standard uniform office lighting was found to provide satisfactory visual conditions but comparatively lower ratings for room quality and occupant well-being.

Rather than advocating a single lighting solution, DIAL concluded that high-quality workplace lighting should combine multiple lighting components—including ambient, indirect, wall-washing, and accent lighting—with user-adjustable controls. Their study further emphasized that no single lighting concept can simultaneously optimize visual performance, spatial perception, and individual well-being for every user. Instead, lighting should be adapted to the requirements of the task, the architectural environment, and the occupants themselves—a conclusion that closely aligns with contemporary Human-Centered Lighting and Human-Centered Building Performance principles.

Zumtobel-Fraunhofer Lighting Research

Zumtobel, an architectural lighting firm, has published extensive guidelines and surveys. Their key points as follow.

Luminance Hierarchy

People sense space through luminance contrasts, not just lux. A brightly lit ceiling and walls make a room feel open. Zumtobel emphasizes that “luminance distribution plays a major role for perception and visual comfort”.

Balanced Luminance

To avoid the “cave effect,” they advise illuminating ceilings and walls. One brochure states “Perceptible luminance levels in particular contribute to either a stimulating, open room ambience or a quiet, secluded one”. In practice, this means using indirect uplights or reflective luminaires to raise ceiling luminance.

User Surveys

In a joint Fraunhofer/Zumtobel survey to about 2,148 European offices, where around 62% of workers had exclusively direct or indirect lighting in their space. Yet 82% of respondents preferred a direct-indirect mix, noting it enhanced well-being. As one white paper summarized, “direct-indirect lighting has a positive impact on the well-being of users,” but most offices (≈60%) do not provide it.

Zumtobel’s commercial literature illustrates these points with case studies offices that switched to luminaires with both uplight and downlight report “higher perception of spaciousness and lower glare complaints,” and companies often reconfigure ceilings (e.g. cove lighting, luminous panels) to achieve uniform brightness.

ERCO Lighting Philosophy

From Illuminance to Perception-Oriented Lighting

Design Philosophy

ERCO has consistently argued that lighting quality cannot be evaluated solely by horizontal illuminance. Instead, lighting should be designed around human visual perception, emphasizing the distribution of luminance across the entire visual field.

Their philosophy, known as Qualitative Lighting, is built on Richard Kelly's three-layer model: Ambient Luminescence, Focal Glow and Play of Brilliance. Unlike conventional engineering approaches that prioritize lux values, ERCO proposes that occupants primarily experience architecture through luminance relationships and visual hierarchy.

Vertical Illuminance

One of ERCO's strongest research themes is that vertical surfaces dominate human perception. People spend relatively little time looking at the horizontal workplane. Instead, the visual field is primarily occupied by walls, partitions, faces, displays and architectural elements.

Consequently, increasing vertical illuminance often improves perceived brightness more effectively than increasing horizontal illuminance. For office environments this means that wall illumination contributes significantly to perceived openness, facial recognition, communication quality, visual orientation and spatial comfort.

Wallwashing

ERCO is perhaps the strongest advocate of wallwashing among lighting manufacturers. According to their research, evenly illuminated walls create several perceptual benefits larger perceived room dimensions, brighter interiors without increasing energy, improved visual adaptation, reduced contrast fatigue and stronger architectural identity.

This aligns closely with Houser's findings that brighter walls and ceilings increase perceived brightness despite identical desk illuminance.

Visual Hierarchy

ERCO emphasizes that lighting should guide visual attention. Rather than distributing identical illuminance everywhere, they advocate creating hierarchy through controlled luminance.

Hierarchy improves navigation, cognitive orientation, object recognition and architectural legibility. This concept extends beyond workplace efficiency into psychological comfort by reducing unnecessary visual complexity.

Implication for Direct–Indirect Lighting

ERCO rarely specifies an ideal direct/indirect ratio. Instead they recommend designing luminance distribution so that ceilings remain visually active, walls contribute to room brightness, workplanes receive adequate task illumination, glare is minimized and visual hierarchy remains clear. This naturally favors balanced direct–indirect systems over purely direct lighting.

Panasonic Lighting Research

Panasonic's SmartArchi lighting design framework introduces Feu, a quantitative index for estimating perceived spatial brightness.

Human Sense of Brightness (Feu)

Perhaps Panasonic's most unique contribution is the development of Feu, a quantitative index that estimates perceived spatial brightness. Instead of asking: "How many lux are on the desk?"; SmartArchi asks: "How bright does the entire space feel to occupants?"

Feu combines luminance information from the visual environment to predict subjective brightness more accurately than horizontal illuminance alone. Panasonic positions this as a bridge between photometric measurements and human perception.

Luminance-Based Lighting Design

SmartArchi promotes lighting design based on wall luminance, ceiling luminance, spatial brightness, visual adaptation and glare reduction rather than relying solely on desk illuminance.

Integration with Architecture

Panasonic emphasizes that lighting fixtures should become part of architecture rather than stand apart from it.

Their four SmartArchi principles are Light, Design, Materials, Quality and Spatial Environment. The objective is not merely to illuminate a building, but to enhance architectural quality and spatial experience.

Office Lighting Research

Panasonic also applies SmartArchi concepts to contemporary workplaces through Activity Based Working (ABW) and Activity Based Lighting.

Their recommendations include brighter vertical surfaces, direct–indirect pendants, low-glare luminaires, lighting optimized for collaboration, lighting optimized for focus work and adaptive lighting scenes for different work modes.

Rather than one uniform office lighting condition, Panasonic proposes tailoring lighting to specific activities such as collaboration, focused work, presentations, and relaxation.

Fagerhult Lighting Philosophy

Balanced Luminance Distribution and Visual Ergonomics

Design Philosophy

Fagerhult approaches workplace lighting from a Scandinavian perspective emphasizing visual comfort, sustainability, workplace wellbeing, energy efficiency and human ergonomics. Rather than maximizing lux, they seek balanced luminance throughout the workspace.

Reflected Light

Fagerhult emphasizes that reflected light from ceilings and walls creates softer visual environments than direct beam illumination alone. Benefits include reduced harsh shadows, lower visual adaptation demand, improved brightness perception, and a more natural visual environment.

Glare Control

Their research repeatedly identifies glare as one of the largest contributors to office dissatisfaction.

Recommended strategies include high-quality optics, indirect ceiling illumination, lower luminaire luminance, controlled beam angles and appropriate UGR values.

Reducing glare improves visual comfort, sustained concentration and occupant satisfaction.

Office Wellbeing

Fagerhult links lighting quality with workplace wellbeing through several pathways.

Sustainable Workplace Lighting

Balanced direct–indirect lighting allows lower installed power, improved perceived brightness, daylight integration, adaptive dimming, and reduced operational energy.

Targetti Lighting Philosophy

Design Philosophy

Targetti treats lighting as an architectural material. Their publications emphasize that lighting shapes how people emotionally experience architecture.

Rather than ask: "How much light?"; they ask: "What atmosphere does the light create?"

Spatial Perception

Targetti research highlights that luminance gradients influence perceived room proportions, enclosure, openness, intimacy and prestige. Direct lighting often creates strong localized brightness. Balanced indirect lighting generates more continuous spatial perception.

Visual Comfort

Targetti places significant emphasis on luminance uniformity, soft transitions, glare reduction and shadow quality. These contribute to environments perceived as relaxing, elegant and comfortable.

Human-Centered Workplace

Targetti increasingly integrates circadian principles, daylight integration, adaptive controls and occupant wellbeing with architectural lighting.

TRILUX Lighting Philosophy

Lighting for the New Work Environment

Design Philosophy

TRILUX frames lighting around modern workplace transformation. Offices are no longer static desk environments. Instead they include collaboration, hybrid meetings, focus work, creativity, informal interaction. Lighting should therefore become adaptive.

Direct–Indirect Luminaire Strategy

TRILUX strongly recommends suspended direct–indirect luminaires for contemporary offices.

Benefits include brighter ceilings, lower glare, improved vertical illuminance and enhanced spatial quality. This closely aligns with Houser, Boyce and Zumtobel.

Vertical Lighting

TRILUX emphasizes that office lighting should illuminate faces, walls and communication zones rather than focusing exclusively on desks. Vertical illumination improves teamwork, video conferencing and interpersonal communication.

Workplace Productivity

TRILUX notes that comfortable lighting supports concentration, collaboration, reduced visual fatigue and employee satisfaction. However they acknowledge that productivity gains arise from the combined lighting environment rather than direct–indirect ratio alone.

Energy Efficiency

TRILUX integrates daylight harvesting, occupancy sensing, tunable white, intelligent controls with direct–indirect luminaires to simultaneously improve experience and reduce energy.

Bartenbach LichtLabor Lighting Research

Brightness Engineering and Visual Neuroscience

Among all lighting research organizations, Bartenbach LichtLabor arguably provides the strongest scientific bridge between building physics, visual perception, and neuroscience. Their work has profoundly influenced modern European lighting design.

Perceptual Brightness

Bartenbach repeatedly demonstrates that Brightness perception is determined primarily by luminance distribution rather than illuminance magnitude.

This explains why offices with identical desk lux can appear dramatically different.

Luminance Psychology

The human visual system evaluates scenes based on luminance gradient, contrast, adaptation, spatial brightness rather than lux measurements.

Daylight Integration

Bartenbach is internationally recognized for integrating daylight with electric lighting.

Their research emphasizes preserving daylight dynamics, minimizing glare, maximizing diffuse skylight, complementing daylight using indirect lighting rather than overpowering daylight with artificial illumination.

Glare Research

Their glare studies emphasize that discomfort depends on source luminance, background luminance, adaptation state, viewing direction rather than glare index alone.

Indirect lighting helps reduce discomfort by increasing background luminance and lowering contrast ratios.

Evidence-Based Lighting Design

Perhaps Bartenbach's greatest contribution is the concept that lighting design should integrate neuroscience, psychology, architecture, photometry, daylight science and building physics instead of relying on illuminance standards alone.

Philips/Signify Lighting Research

Philips (now Signify) has likewise conducted office lighting research, focusing heavily on biological and human-centered aspects.

Vertical Illuminance & Circadian

Philips promotes higher vertical light levels on people and walls, not just on desks. Their “Lighting University” training and UL DG 24480 guidance encourage designs that deliver ~300–500 lx vertical illuminance at eye level, achieving ~250 lx melanopic EDI for daytime offices. In Q&A materials, Signify scientists note that 250 m-EDI (melanopic equivalent daylight illuminance) is recommended for healthy adult circadian support. Achieving this often requires substantial uplight and cool-white spectra in the morning.

Visual Performance & Satisfaction

Philips-sponsored papers report that well-designed ambient lighting (diffuse ceiling/wall illuminance, tunable-white options, dynamic dimming) improves self-rated comfort, alertness, and collaboration in offices. For instance, studies have found that adding wall-wash or indirect components increases occupants’ ability to see faces and monitor screens without glare, indirectly benefiting communication and reducing visual strain. (We did not find a specific quote to cite here, but this aligns with Philips’ emphasis on “visual comfort”.)

Energy & Controls

Signify case studies note that enabling local control (task lamps or personal overhead controls) boosts satisfaction. One Philips study of user-controlled desk lamps reported “90% of workers had sharper vision and improved eye comfort” when allowed to set intensity/CCT.

In summary, Philips reinforces that beyond lux, lighting design must consider spectral-timing and vertical distribution. Their insights complement Zumtobel’s both stress diffuse ambient light and individual adjustment. In product literature, Philips lamps and systems often include both direct and indirect modes (e.g. floor lamps with uplight) to achieve this balance.

Lighting Industry Consensus

• Luminance distribution matters more than horizontal illuminance.

• Vertical surfaces should be illuminated to enhance perceived brightness and spatial quality.

• Lighting should be layered rather than uniform, integrating task, indirect, wall-washing, ambient, and accent lighting according to the space and task.

• The goal is to optimize the overall visual experience, not simply achieve a target illuminance level.

Synthesis of Lighting Industry Finding

Collectively, lighting industry finding demonstrates a paradigm shift from illuminance-based engineering toward perception-oriented, human-centered lighting design. Although organizations use different terminology—including Qualitative Lighting, Human-Centric Lighting, Perception-Oriented Lighting, Visual Ergonomics, Brightness Engineering, and Human Sense of Brightness.

They consistently conclude that lighting quality depends on luminance distribution, perceived spatial brightness, vertical illuminance, glare control, daylight integration, and the coordinated use of multiple lighting components, rather than horizontal illuminance alone. Rather than relying on a single lighting strategy, leading industry research advocates layered lighting solutions that combine ambient, direct, indirect, wall-washing, and accent lighting to optimize visual comfort, spatial perception, and occupant well-being.

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Post-Occupancy Evaluations & Occupant Feedback

Real-world office surveys echo the lab findings. Occupants under mostly downlighting frequently report a laundry list of complaints as below.

Glare & Eyestrain

“Too much glare,” “bright fixtures shine in my eyes,” “reflections on my monitor,” “tired/fuzzy eyes” are common refrain.

Spatial Feel

Workers describe ceilings as visually dark or the office as “gloomy,” “cave-like,” or “claustrophobic” under direct-only lighting. When uplights are added, they say the room feels larger and brighter.

Aesthetic/Energy Impressions

Pure direct lighting often feels “stark,” “industrial,” or “clinical.” By contrast, indirect components yield comments like “the office feels more inviting” or “the ceiling lightens up the room.”

Health/Mood

Indirect lighting often yields fewer reports of headaches or eye strain. A survey by Zumtobel (n=400 offices, USA) found that two-thirds of employees preferred some indirect component, citing increased well-being.

For example, in Hedge’s 1989 office study, workers under the indirect uplights noted the lighting was “more appropriate for computer work,” and “less interference” with their tasks (reflection/glare). Conversely, the direct-light zones had frequent “screen glare” complaints.

By optimizing the balance between indirect and direct lighting, reflective glare on computer screens and glossy magazines can be significantly reduced, improving visual comfort and readability.

Boyce (2006) summarised occupant comments users found the mixed systems “softer,” “more visually pleasing,” and “easier on the eyes.” Although such direct quotes cannot be embedded in this report, numerous POE studies document the same pattern balanced luminance distributions dramatically increase lighting approval.

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Human-Centered Office Lighting Summary

Subjective versus Objective Observations

Subjective Satisfaction

Direct–indirect setups consistently receive higher ratings for comfort, attractiveness, and overall lighting quality. Occupants explicitly prefer balanced schemes (~40–60% uplight) over direct-only.

Glare and Comfort

Self-reported glare and visual fatigue are significantly reduced under indirect or mixed systems. Tasks like working at a VDT (computer) become “less stressful” with more diffuse uplight.

Cognitive Performance

As noted, objective task performance (reading speed, accuracy, vigilance, etc.) shows little to no difference between direct vs mixed lighting. The main effect of better lighting is on well-being and psychological comfort, not on basic acuity or reaction time.

Thus, design decisions here hinge on occupant experience, not just numeric lux. People “judge how the entire room makes them feel,” so improving wall/ceiling brightness yields outsized subjective benefits.

Visual Comfort & Satisfaction

Luminance vs Illuminance

A recurring theme is that ceiling and wall brightness heavily influence how bright a room feels. In laboratory measurements, giving equal lumens, spaces with higher ceiling luminance are rated brighter. This is because the human visual system integrates peripheral light and adapts less when the scene is uniform. Zumtobel summarizes “People perceive their environment via differences in luminance; special stimuli catch their attention.”

Glare and Adaptation

Direct-only fixtures (e.g. parabolic downlights) can produce high peak luminance (direct view of bare tubes or LED arrays) and dark surrounds, leading to glare and eye fatigue. Indirect or shielded systems spread light and raise background luminance, reducing eye strain. Studies like Boyce et al. noted fewer “screen glare problems” under indirect lighting. Signify’s glare research likewise shows that uniform-luminance fixtures are easier on the eyes.

Subjective Satisfaction

Across multiple post-occupancy evaluations, employees consistently express preference for softer, more even lighting. In Lu et al.’s words, when more light was directed upward “observers also express more preference” and described the space as more “pleasure[able]”. Similarly, de Vries et al. (2021) found that rooms were rated as more attractive when uplight was increased. Industry surveys echo this: workers often say mixed lighting makes them feel less fatigued and more productive, whereas bright direct-only strips cause “eye strain” and a “gloomy” feel.

Typical Quote (literature)

“Indirect lighting gave a spacious impression while direct light decreased the perceived spatial size.” (from prior reviews).

Cognitive Performance and Alertness

Controlled experiments consistently show no clear cognitive advantage from direct vs. mixed lighting when desk illuminance is equal.

• Boyce et al. found no significant effect of lighting condition on task performance (typing, reading).

• Lu et al. reported no significant differences in attention or calculation tests across light distributions.

• Fostervold (2008) likewise observed no effect of direct/indirect ratio on cognitive tests.

In other words, merely splitting light between uplight/downlight does not seem to speed up reaction times or accuracy of simple tasks, provided overall lux and spectrum are unchanged.

However, lighting can influence alertness indirectly by affecting circadian rhythms and comfort. Higher uplight usually means more blue-rich light reaching the eyes (if spectra identical), which can boost daytime alertness. Philips/Signify highlights that meeting a melanopic-EDI target (∼250 lx) likely requires strong uplight in the morning. Moreover, environments that feel comfortable and less fatiguing (as with indirect lighting) may sustain concentration longer through the day.

Finally, note individual variability de Vries et al. (2021) identified two clusters of users. One group clearly preferred bright, diffuse spaces (and potentially enjoyed alertness from it), while another group was relatively “sensation-avoiding” and indifferent to luminousness. This suggests offering personal control (dimming, task lamps) to suit different preferences.

Daylight Integration and Circadian Lighting

Contemporary office design merges electric lighting with daylight and circadian guidelines.

Daylight Partnership

Aim to amplify and supplement daylight with electric light, not fight it. As Zumtobel’s survey notes, 72% of employees still use electric lights >6 hours/day even in summer. To harmonize with windows, designers use high ceiling reflectance and uplights so that electric light feels continuous with incoming sky light, minimizing sudden contrast when daylight wanes. Automated dimming can gradually increase electric uplight as sun drops.

Vertical Illuminance Targets

Well Building Standard and industry workshops (UL DG 24480/CIE S 026) now recommend specific daytime vertical illuminance levels (e.g. 300 lx Ev or ~250 m-EDI) for circadian benefit. Achieving these often requires a high indirect component and/or wall-washers. For example, Signify’s experts note a 60-year-old may need 5× the light of a 20-year-old to achieve the same retinal stimulus. Thus, mixed lighting must be tuned in both amount and spectrum (cool white for morning uplift, warmer later).

Dynamic Controls

Philips research emphasizes tunable white (e.g. NatureConnect) and scene-setting. Offices can employ scheduled or sensor-driven shifts high intensity cool light in morning (balanced direct + strong uplight), gradually dimming and warming towards evening to prepare for sleep. In all cases, maintaining a well-lit ceiling helps sustain higher mel-EDI levels without increasing desk glare.

Glare Management with Daylight

Integrating blinds or electrochromic glazing controls is essential. When direct sun is present, reducing direct overhead light (dimming downlight) and increasing soft indirect light can mitigate eye discomfort while still keeping the room bright.

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Practical Design Implications

Luminaire Selection

Favor fixtures with both up- and down-components (e.g. troffers with luminous uplight panels, cove/wall-wash luminaires). Use wide diffusers or perforated ceilings to distribute light. For task lighting, choose fixtures with low-glare optics (UGR<19) or indirect table lamps. Consider bi-directional floor lamps or pendant systems (e.g., Zumtobel’s “Sequence”) that independently control uplight/downlight.

Surface Reflectance

Maximize ceiling reflectivity (~0.7–0.8) and maintain mid-to-high wall reflectance (~0.5–0.7) to bounce indirect light. Dark floors (<0.3 reflectance) are fine. This ensures that even moderate uplight contributes to overall ambience.

Controls and Zoning

Provide separate controls (switches or DALI channels) for direct vs indirect channels. This lets occupants or automatic systems adjust the uplight/downlight ratio. Daylight-linked sensors should adjust both uplight and downlight to maintain uniform room brightness. Individual task lamps (especially with uplight options) enhance personalization.

Direct - Indirect Light Ratio

Studies like Houser (2002) explicitly recommend ≈60% indirect for general preference, while Philips signage suggests higher downlight (~70%) may be acceptable in focused task zones (see private office).

Typical Direct–Indirect Lighting Ratios Based on Research and Industry Practice

Note: Ratios are evidence-informed design recommendations synthesized from Houser et al. (2002), Boyce et al. (2006), de Vries et al. (2021), and guidance from ERCO, Zumtobel, TRILUX, Panasonic, Signify, and Bartenbach. Actual ratios should be adjusted according to ceiling height, room geometry, surface reflectance, daylight availability, visual task, and luminaire photometric distribution.

Lighting Levels

Maintain standard desktop illuminance (300–500 lx), but ensure vertical face illuminance of at least 150–300 lx (higher in morning). Use circadian design tools (e.g. CIE S 026 calculators) to target melanopic lux.

Glare & Visual Comfort

Even with indirect components, watch for glare from windows, monitors, or vertical surfaces. Use blinds and anti-glare filters as needed. Choose bulbs/luminaires with high CRI (>90) and smooth spectral power distributions. Avoid extreme contrasts (e.g. very bright downlights with dark ceilings).

Integration with WELL/LEED

Balanced lighting can help meet WELL v2 Light feature (L03 “Visual Lighting Design”) by improving visual comfort and access to high-quality light. It also supports circadian metrics (WELL L04, UL DG 24480) by boosting melanopic content when needed.

Conclusions

Synthesizing academic trials and industry guidance yields a clear principle maximize total luminous environment quality, not just desk lux. Direct-only schemes, while simple, tend to under-illuminate ceilings and walls, leading to poorer comfort and satisfaction. By contrast, mixed direct–indirect lighting achieves high task illuminance and ample ambient brightness. Across dozens of studies and surveys, occupants feel these spaces are brighter, more expansive and less fatiguing, even if measured lux at the desk is unchanged.

We therefore recommend that modern office lighting design embrace indirect light as a first-class element. Equip lighting layouts with uplight channels, ensure dynamic control, and aim for significant vertical/melanopic exposure. The extra effort pays off in human-centered metrics (comfort, well-being, perception) that no lux meter can capture.

Evolution of Office Lighting Concept

Over the past four decades, office lighting has evolved from an illuminance-based engineering discipline toward a perception-oriented, human-centered design discipline. The evidence consistently demonstrates that lighting quality is defined not only by how much light reaches the workplane, but by how effectively light is distributed throughout the visual environment. Future office lighting should therefore optimize luminance distribution, vertical illuminance, glare control, daylight integration, and adaptive controls to support comfort, wellbeing, collaboration, and Human-Centered Building Performance.

About ALTA Integra

This review reinforces ALTA Integra's Human-Centered Building Performance philosophy exceptional workplaces are not created by meeting illuminance standards alone, but by integrating lighting, acoustics, thermal comfort, indoor air quality, and building physics into a unified design strategy that enhances human health, perception, and performance.

ALTA Integra brings together expertise in Architectural Building Physics—including Lighting, Acoustics, Thermal Comfort, and Indoor Air Quality—to create healthier, more comfortable, and higher-performing environments. Through evidence-based design and multidisciplinary collaboration, we strive to advance Human-Centered Building Performance for projects across diverse building sectors.

#light #lights #lighting #lightlife #lightingdesign #lightingdesigner #lightingconsultant #architecture #architecturalligthing #interiordesign #interiorlighting #ceilinglight #lightingideas #lightinginspiration #officelighting #lightproject #lightingproject #office #officedesign #openplanoffice #corporaterealestate #facilitymanagement #humanresourcedevelopment #health #wellbeing #productivity

Accurate acoustic result in design and commissioning of modern office

The measured Field Sound Transmission Class (F-STC) of the glass partition and door is meet target design

Accurate acoustic result in design and commissioning of modern office

When designing a modern office, we always concern about the following question.

How much is the background noise in the meeting room after final construction?

How much is the final sound transmission loss after all materials assembly on-site?

Will it compy to the Acoustic Standard required?

Always looking for better acoustic modeling technique to be able to predict Sound Transmission Class to reduce investment cost while maintaining acoustic performance standard

ALTA Integra has succeeded in design and commissioning several world-class projects accurately because we are always eager to study, learn, and perfecting our standard operating procedure.

Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being. Let’s join our mission to share this belief and passion to make our world a better place.

Always learn and invest to improve acoustic measurement, equipment and methodology

#acoustics #roomacoustics #acousticdesign #acousticengineer #interioracoustic #interiordesign #interiordesignproject #architecturalacoustic #officenoise #officeinteriordesign #meetingroom #architecture #interiordesign #interiorlighting #office #officespace #healthy #healthylife #wellbeing #architecture #architectureproject #productivity

Acoustic and Lighting Integration Improve Workplace Satisfaction

How Acoustic and Lighting Integration Design Above Workstation Improve Workplace Speech Privacy and Light Quality?

An acoustic cloud with absorptive material will reduce overall perceived loudness, annoying sound, and increase the privacy index between workstations. The worker can work more productive and improve mental health.

Biomimicry lighting adapting natural light of direct sunlight and ambient of diffuse skylight. The programmable control system of Direct Task Lighting above workstation and Indirect Lighting to Ceiling reduce eye strain, improve visual acuity and wellbeing.

Concept Design 3D Preview

Concept Design 3D preview shows acoustic and lighting design cloud above each workstation.

Triple function cloud

Cloud triple function as an acoustic sound absorber, direct-indirect lighting hanger and interior design decorative

Acoustic Cloud

Acoustic Cloud will absorb human voice and other disturbing sounds as well as reducing reverberation time.

Lighting Cloud

Direct and Indirect Lighting mount on the workstation, mimicking direct sunlight and diffuse skylight.

Alta Integra integrates smart integration between acoustic and lighting design elements in designing a future healthy office. Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being. Let’s join our mission to share this belief and passion to make our world a better place.

#light #lights #lighting #lightingdesign #lightingdesigner #lightingconsultant #ceilinglight #modernlighting #lightingideas #lightinginspiration #lightproject #lightingproject #acoustics #roomacoustics #acousticdesign #acousticengineer #interioracoustic #interiordesign #interiordesignproject #architecturalacoustic #officenoise #officeinteriordesign #meetingroom #office #officespace #healthy #healthylife #wellbeing #productivity #architecture #architecturalligthing #interiordesign #interiorlighting #architecture #architectureproject

Daylighting Modeling Simulation that meets EN 12464-1

Daylighting Modeling & Simulation can predict the Daylight Quality Factor EN 12464-1

Daylighting Modeling Simulation that meets EN 12464-1

Using daylight in the office can reduce electricity energy usage and improve occupant health. If we want our workplace light by daylight then we want to make daylighting modeling and simulation to meet The EN 12464-1 defines daylight qualitative factors such as:

Agreeable luminous environment,

Harmonious luminance distribution,

Adequate illuminance for the interior areas,

Task areas or activity areas listed in the tables “Schedule of lighting requirements”,

Good uniformity,

Limitation of direct and reflected glare including veiling reflections,

Correct directionality of lighting and agreeable modeling,

Appropriate color rendering and color appearance of the light,

Avoidance of flicker and stroboscopic effects,

Quality of daylight,

Variability of light.

Alta Integra integrates harmonious integration between lighting and daylight factors in designing a healthy environment office. Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being. Let’s join our mission to share this belief and passion to make our world a better place.

#light #lights #lighting #daylight #daylighting #lightlife #daylightingdesign #lightingdesign #lightingdesigner #lightingconsultant #architecture #architecturalligthing #interiordesign #interiorlighting #greenbuilding #sustainability #lightproject #lightingproject #energysaving #office #officespace #healthy #healthylife #wellbeing

Psychology study of Built Environment Design: Approaching or Leaving?

Design factor: interior design, circulation, color and Ambient factor: Lighting and Soundscape create inviting mood

Psychology study of Built Environment Design: Approaching or Leaving?

In designing hospitality project ALTA Integra implements psychology study of Stimulus Organism Response Model (SOR) by Mehrabian and Russel 1974. The study said that external “STIMULUS” such as Design, Ambient and Social Factors, will influence “ORGANISM” or an emotional state that excites Pleasure, Arousal, and Dominance (PAD). This emotional state will ignite “RESPONSE” action to approach the place if the person sense pleasure, feels arouse, and finally decide to approach because of a dominant thought.

Mehrabian & Russel Stimuli, Arousal, Response (SOR) model

Design and Ambient factors in STIMULUS are Interior design, Color palette, Lighting design, and Soundscape design. Alta Integra integrates harmonious blending between those factors in designing an inviting VIP Karaoke Place. Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being. Let’s join our mission to share this belief and passion to make our world a better place.

#karaoke #sing #singalong #singer #bar #bardesign #nightlife #music #musictherapy #interiordesign #lightingdesign #roomacoustics #architecture #wellbeing #wellness #musiclife #musiclifestyle

Beautiful design, beautiful sound, for music therapy

Beautiful Place, beautiful music for your health

Music therapy offers people a creative and accessible way of expressing their feelings and processing their experiences. It can be an effective and enjoyable tool for reducing the symptoms of numerous conditions, including depression and anxiety.

Alta Integra creates harmonious blending between Music Reproduction, High-End Audio System, Architectural Acoustic, and Architectural Lighting and Interior Design. We love music and we always create innovative designs such as soft glow light from a 2-dimensional acoustic diffuser ceiling to improve visual and listening experiences as no one ever did before.

Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being. Let’s join our mission to share this belief and passion to make our world a better place.

#highendaudio #music #musictherapy #interiordesign #lightingdesign #roomacoustics #architecture #wellbeing #wellness #musiclife #musiclifestyle

Brightness Management Strategies of IWBI Visual Lighting Design

International WELL Building Institute - IWBI feature 53 Visual Lighting Design of Light Concept, part 2 Brightness Management Strategies: brightness contrast helps create visual hierarchy in space and increase productivity, but too much contrast may cause uncomfortable glare or eyestrain.

Light performance verification is needed to assure that the project has built as planned. The image is shown ALTA Integra’s lighting designer is measuring vertical light illumination for performance verification.

Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being. Let’s join our mission to share this belief and passion to make our world a better place.

#lightingdesign #interiordesign #renovation #renovationproject #architecture #arsitekindonesia #architecturallighting #wellness #wellbeing #health #productivity #humanresources #office #officedesign

Access to safe drinking water

In developed country, water in riverbank is polluted with sediment and dangerous chemical

SAFE DRINKING WATER ACCESS

The World Health Organization (WHO) reports that almost one billion people lack access to safe drinking water worldwide and that two million annual deaths can be attributed to unsafe water, sanitation, and hygiene.

ALTA Integra provides International WELL Building Institute - IWBI certification because we believe our body and mind quality is shaped by the space we live and work. Architectural Building Physics such as Acoustic, Lighting, Water, Air Quality, etc play important role in making a better space for human-being.

Let's join our mission to share this belief and passion to make our world a better place to live in.

#greenbuilding #Wellbeing #wellcertification #certification #sustainability #sustainable #sustainableliving #water #waterquality #drinkingwater #architecture #arsitekturindonesia #interiordesign #hdiindonesia

Evidence of Health & Green Building Benefit

ALTA integra provide daylight and natural air ventilation for Sport Hall Kolese Kanisius Renovation

All over the world, the evidence is growing that green and healthy buildings bring multiple benefits. They provide some of the most effective means to achieving a range of global goals, such as addressing climate change, creating sustainable and thriving communities, and driving economic growth.

Stepped ceiling to reflect daylight with sound absorbing creates healthy ambient

ALTA Integra provides green building design optimization such as energy modeling, daylighting modeling, and natural ventilation modeling. ALTA Integra provides green and health building certification services such as Greenship, Green Mark, LEED, and WELL Certification.

#greenbuilding #certification #sustainability #sustainable #sustainableliving #airquality #buildingmaterial #lighting #comfort #performance #architecture #arsitekturindonesia #interiordesign #hdiindonesia #building #hvac

Why Entertainment Place needs Building Acoustics and Environmental Noise Control Design?

HAVING FUN without disturbing others

The sound that comes out from Night Entertainment Venue in the high-density building will disturb people’s sleeping. The low-frequency fast pace music will wake people who want to have a good night's sleep. Lack of sleep can cause stress, headache, heartache, and cancer. Since 2010, ALTA Integra has succeeded in more than 50 projects designing high-level sound entertainment places and reduced community noise complaints as per Environmental Ministry Regulation. Reducing noise exposure to humans will increase t heir health and life quality because we believe our bodies and minds are shaped by the space we live and work in.

Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being. Let’s join our mission to share this belief and passion to make our world a better place.

#music #club #nightlife #livemusic #rockconcert #housemusic #noise #community #humanrights #wellbeing #bettersleep #hearingloss #environment #environmental #environmentalsustainability #sustainability #health #architecture #building #interiordesign #design

* due to the Non-Disclosure Agreement (NDA) with our client, the image posted just an illustration from photo stock.

Why does a city need city-wide air quality and noise planning?

Illustration Image Jakarta International Stadium under construction 2020

HEALTHY CITY

ALTA Integra provides strategic city noise and air quality planning, modeling, simulation, mapping, and monitoring including environmental noise, road traffic noise, railway noise, and aircraft noise using state-of-the-art outdoor noise and air quality prediction software CADNA-A.

ALTA Integra believes our body and mind are shaped by the space we live and work. Architectural Building Physics such as Acoustic, Lighting, Thermal, and Air Quality play important role in making a better space for human-being.

Let's join our mission to share this belief and passion to make our world a better place to live in.

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