Illuminating wellbeing: Rethinking indoor light implementation

by arslan_ahmed | February 26, 2024 4:00 pm

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By Robert Soler

A specifier plays a critical role in ensuring buildings are designed and constructed to meet and exceed the needs of the people using those spaces. Many design elements go into every stage of the construction process, from initial drawings to materials selection, but there is one building design aspect often overlooked: the impact of indoor lighting.

When thinking about lighting a room, most people immediately think about brightness and ambiance: can occupants see well inside? Is it the right atmosphere for whatever activities are happening in this room? Does the lighting highlight the most important areas?

What is often overlooked when designing a building is the impact of lighting on the health and wellness of the occupants, regardless of whether it is a commercial building or a residential structure. Research shows that light is vital for health and wellbeing and is linked to the body’s natural rhythm.¹

 Functional lighting reimagined

Having appropriate lighting inside a building directly influences the productivity, mood, sleep patterns, etc., of its inhabitants. This information is imperative for businesses who want to ensure their employees are happy and efficient, and even businesses such as hotels and travel companies who want to ensure their visitors have a comfortable experience. The use cases for wellness lighting 
are endless.

While typically functional lighting design revolves around providing the mandatory illumination needed for everyday activities, a case should be made for elevating the understanding of what “mandatory” illumination is. It is more than just being able to see well inside a room—occupant health should be a necessary part of the decision.

Science-backed results

People might notice they are happier on sunny days than they are on cloudy, stormy days and this is, in some cases, due to the amount of light they are getting. Beyond improving moods, the amount of light a person gets changes them on a biological level.

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In a 2022 study published in PLOS Biology, researchers found light exposure is directly connected to more than just vision and productivity; it is also directly correlated to sleep health and circadian rhythms, cognitive function, and mental health wellness.² The data states light not only helps manage symptoms of many of these aspects of health but is also related to the diagnosis itself. If someone is experiencing changes in their health, increasing exposure to light may be the solution, or at least part of it.

In fact, light is important for wellbeing at all stages of life, from infancy to adulthood. A fussy baby may need brighter lighting in their nursery to improve their mood and research indicates that patients with dementia have seen improvement in their memory in homes with more dynamic lighting.³

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With this knowledge, the role of the specifier also includes keeping the health impacts of lighting in mind as they work on projects. Who are the people that will be spending the most time in each building and what are their specific needs? Offices, daycare centers, hospitals, retirement homes, and more, all have benefits they can reap from proper lighting.

Daytime light versus nighttime light

While it may sound like a cliche, the truth is, not all light is created equally. Different types of light signal to the brain when it is time for specific activities and energy levels. Therefore, different lighting is needed during the day than at night.

There is a new metric, which determines how healthy light is, known as vertical melanopic equivalent daylight illuminance (EDI). Melanopic EDI (m-EDI) is a measurement adopted by the International Commission on Illumination (CIE) that captures the full impact of light and how the body perceives it. There has been a push in the lighting industry to set a precedent in circadian lighting and m-EDI is finally the measurement to help establish this guideline.

The agreed upon scientific recommendation, and WELL Standard, is receiving a minimum of 250 m-EDI vertically at the eye during the daytime, rich in blue spectrum to simulate daylight. This baseline gives designers a way to create spaces that provide an appropriate amount of light.

Unfortunately, because m-EDI is a new measurement (developed over the past five years), much of today’s traditional or existing lighting only gets 35 percent of the light needed for optimal wellbeing. Color tuning solutions will increase this to 50 percent of the wellness criteria. Again, woefully short of meeting one’s daily needs. Even windows have a difficult time reaching these criteria.

Based on the author’s research, to get enough light from windows, one needs to be facing it directly. Facing a wall next to a window will only yield about 50 percent of the criteria. The measurement, m-EDI, proves it is not enough to merely dim the lights or change the temperature to get the proper m-EDI needed; the light spectrum, direction, and color of the light must be taken into consideration.

Further details on how these factors play a role is illustrated here. Note: currently it is not mandatory to meet these criteria, but support for these criteria is expected from the Illuminating Engineering Society (IES) and the International Commission on Illumination (CIE) by 2024.

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The human eye is looking for high amounts of vertical m-EDI during the day and low amounts at night. A blend of sun and sky will give a person the most m-EDI, making it the most beneficial for daytime use. High m-EDI during daytime boosts productivity, decreases depression, improves mood, energy, and alertness. For office spaces in particular, circadian lighting should be taken into consideration, aiming for a minimum 250 EDI (as mentioned earlier), and it is best to incorporate lighting gradients with cooler tones and blue light to optimize workers’ energy and focus. With more companies transitioning to remote work or offering hybrid models, the same can also be considered for residential buildings.

For nighttime, the lighting should be as warm as possible with a maximum of 10 EDI about two to three hours before bed. Finally, at night, when sleeping, the darker the better. Fully removing any blue light exposure and maintaining a maximum of one EDI. Think of a natural sunset with its warm tones and gradients; red or amber light promotes natural melatonin production, building relaxation and sleepiness, which helps in winding down for bed.

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The variety of light needed throughout the day is understated. The wellness criteria has a day-to-evening ratio of 25:1. Standard color tuning only provides a 2:1 ratio. To achieve true health and wellness benefits, different spectrum, wavelength, temperature, and direction of light at different times of day. This is why dynamic lighting is necessary in all buildings. Prioritizing this new metric, vertical m-EDI, in any space, whether it is commercial, residential, or multiuse has many benefits. Even in contemporary buildings with ample natural light sources (e.g. windows, patios, doors, etc.), using the right light is not just an investment in the physical space, but an investment for occupant wellbeing.

 The sun-sky spectrum

As mentioned previously, one needs a minimum amount of vertical m-EDI throughout the day, which typically comes from natural sunlight. Luckily, for those who work and spend most of their time indoors, they are still able to get the appropriate amount of EDI from electric lighting. To implement electric lighting that supports wellness, there are a few ways to hunt down the right solution for a particular project. The key is to look for products designed to mimic the sun and the sky. It is more than just installing color-changing light bulbs, but rather about incorporating the blue reflection of the sky through different gradients of light temperatures.

One way to achieve this is using a dynamic electric light capable of transitioning throughout the day to offer stronger blue light and blue to white gradients during daytime and warmer amber to red gradients in the evening. For example, daylight on an overcast day is 6,500 K, while on a bright, sunny day, nothing is 6,500 K. Daylight is comprised of blue sky of 8,000 K and colder, where sunlight is 5,700 K and warmer.

When people are outdoors, the sun is never directly reaching them—it is always a mixture of the sun and sky that reflect in a specific manner. Throughout the day, the sky grows in the morning, gradually shifting to be brightest towards the peak of the day, and then slowly fades into a sunset. Sometimes there may be clouds, and other times it is bright blue skies. All these variations impact people, therefore, when weighing options, this is the top function to look for in products. Think of it as looking out of a window and seeing a mix of blue skies, clouds, light from different angles, compared to just turning on a light bulb or looking directly up at the sun.

Best practice for wellness-supporting lights

Contrary to popular belief, blue light is not always bad—the human body needs it in certain capacities. When deciding lighting options, the key is to look for technology that disperses blue light. Exposure to the full-spectrum light bodies need can feel uncomfortable to the eye; therefore, investing in lighting that prioritizes a mix of warm- and cool-toned light will help lessen overstimulation. Anything that emphasizes color dispersion is a great place to start.

It is also important to ensure the light fixtures are at an appropriate height. Research states blue light coming from the upper region of the gaze is biologically ideal, as the body is calibrated to the blue sky in nature. It is not always possible to install lighting on the vertical sightline plane, especially when working with high ceilings or nuanced building codes, but it is something to keep in mind and consider what can be done to make it easy on the eye.

Finally, keep an eye out for products that mimic the sun’s cycle to avoid circadian rhythm disruptions. Throughout the day, the sun naturally changes as it transitions through sunrise, daylight, sunset, nighttime, and design teams can find artificial lights that replicate that same gradual cycle. Even if one is working in a room with windows, it is still not enough exposure to signal these time-of-day transitions to the brain. There are many circadian lighting and wellness lighting options available—including desk lamps and individual light bulbs that transition.

Conclusion

For any working environment, it is important to supplement the right artificial light to ensure a healthy quality of life and occupant wellbeing.

The quality and type of light surrounding people in their home, workplace, stores, gym, etc., directly correlates to their quality of life. By rethinking indoor lighting to focus on health in addition to function, specifiers can support the health of building inhabitants for years to come.          CS

Notes

¹ Read the research on the importance of lighting, https://doi.org/10.1016/j.cub.2016.04.011[6].

² See the 2022 wellness lighting recommendations at https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001571[7].

³ Learn more about light and health, www.ncbi.nlm.nih.gov/pmc/articles/PMC8707256[8].

⁴ Review this link for more information on how to quantify m-EDI https://cie.co.at/publications/cie-system-metrology-optical-radiation-iprgc-influenced-responses-light-0[9].

Author

Robert Soler is the cofounder of SkyView, a leader in human wellness lighting technologies. Prior to his work at SkyView, his most prominent work was at Kennedy Space Center, where he was the subject matter expert for NASA‘s circadian lighting system to synchronize astronauts to a 24-hour cycle onboard the International Space Station. He received a fellowship from 
the National Science Foundation (NSF) and currently serves on the light advisory committee for the International WELL Building Standard.

Source URL: https://www.constructionspecifier.com/illuminating-wellbeing-rethinking-indoor-light-implementation/

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