Dynamic Led Lighting & Visual Comfort In An Office Setting
As engineers of lighting layout designs, Houston electrical contractor Blanco Electric Ltd is interested in LED technology as a means to improve human well-being in both professional and consumer environments.
We analyze scientific studies to understand better the impact of LED lighting on office workers' productivity and comfort. This is the case of this study on dynamic LED lighting. Our technology watch helps us design better lighting layouts.
1. Dynamic LED lighting: what is it?
The study titled "Impacts of Dynamic LED Lighting on the Well-Being and Experience of Office Occupants" aims to understand the impact of dynamic lighting on office occupants' health, well-being, and experience.
In this study, "dynamic LED lighting" refers to a lighting system that can vary both the illuminance (the amount of light falling onto a surface) and the correlated color temperature (CCT - the color appearance of the light itself) throughout the day.
Dynamic lighting is designed to mimic the daily variations in natural light, which can have potential benefits for occupants, including increasing satisfaction, improving alertness and performance, and synchronizing human circadian rhythms.
In the context of this study, two dynamic lighting conditions were designed and implemented, each with a specific predefined control scheme that varied the illuminance and CCT levels at different times of the day. The goal was to investigate the impact of these dynamic lighting conditions on the health, well-being, and experience of the office occupants.
2. Conditions of the study
The research was conducted in a living lab with 15 participants working in three office modules for four months. Four lighting conditions were designed and implemented, including two static lighting conditions and two dynamic lighting conditions with a specific predefined control scheme.
Study Design and Methods: This section details the study's design, including the lighting conditions, office configuration, lighting system design, participant selection, and environmental measurement methods.
Behavioral Outcome Measurement Methods: This section explains how the study measured the efficacy of using dynamic light to reduce stress in the office environment while also maintaining productivity and improving sleep quality.
3. Study demographics
The study recruited 15 participants from various work units at a large midwestern medical institution. The participants included 9 males, and the average age was 38.
The researchers set certain exclusion criteria for participant selection. Individuals were excluded if they had a history of:
Diagnosed sleep disorders
Severe vision problems
Sensitivity to light resulting in headaches or seizures
Cognitive abilities interfering with typical office work
Physical disabilities interfering with typical office work
Severe mood disorders
Drug or alcohol dependency
4. Study assumptions
Researchers in this study started with the assumption that dynamic LED lighting, which mimics the natural variations in daylight, could have potential benefits for office occupants. The benefits they hypothesized included:
Increased Alertness: The researchers assumed that dynamic lighting could help increase alertness, particularly in the afternoon when people naturally tend to feel sleepy.
Improved Mood: They also hypothesized that dynamic lighting could have a positive impact on the mood of the office occupants.
Enhanced Sleep Quality: The researchers assumed that exposure to dynamic lighting during the day could improve sleep quality at night.
Improved Productivity: The assumption was that the overall well-being improvements from dynamic lighting could lead to increased productivity.
Note: The document provided does not explicitly define how the researchers measured "productivity" in the context of their study. In many studies of this nature, productivity is often measured through self-reported surveys, where participants rate their own perceived productivity levels. It can also be measured through objective metrics like task completion speed, error rates, or other performance indicators relevant to the work being done.
Increased Visual Comfort and Perceived Naturalness: The researchers also hypothesized that dynamic lighting could enhance visual comfort and make the lighting environment feel more natural.
The study aimed to either prove or disprove these assumptions by observing and measuring the impacts of dynamic lighting on the participants.
5. The results
The study found that the daytime behavioral impacts of dynamic lighting were either positive or mixed. Specifically:
A significant alertness increase was observed in the afternoon, indicating a potential solution to reduce the natural feelings of sleepiness during the workday;
A marginal benefit for mood;
The nighttime impacts include a significant decrease in perceived sleep quality and sleep time after subjects were exposed to dynamic lighting;
No significant differences were observed for mental stress, productivity, visual comfort, or perceived naturalness.
6. A perceived decrease in sleep quality
Did the researchers study the reasons why participants in the study indicated their sleep quality declined markedly after months of exposure to dynamic LED lighting?
The researchers hypothesized that the decrease in perceived sleep quality in the dynamic LED lighting condition (JP-D) compared to the static condition (JP-T) could be due to a decrease in time spent in deep sleep, a restorative sleep stage.
As the dynamic condition progressed, the time spent in deep sleep decreased, indicating that although people slept the same amount, it was not as restorative and restful. This could potentially explain the decrease in perceived sleep quality.
7. Cost/benefit analysis
The researchers did not explicitly conduct a cost/benefit analysis of using dynamic LED lighting in the context of the impact on sleep quality. However, they did acknowledge the negative impacts on sleep quality and sleep time when subjects were exposed to dynamic lighting.
They concluded that the impacts of dynamic lighting on daytime behavior were either positive or mixed, with a significant alertness increase observed in the afternoon and a marginal benefit for mood. However, the nighttime impacts included a significant decrease in perceived sleep quality and sleep time.
The researchers suggested that these findings present additional insights into the non-visual impacts of dynamic lighting and give recommendations for further investigations. They also mentioned that the dynamic lighting control profile may need to be further optimized to generate stronger effects beyond vision, which could potentially mitigate the negative impacts on sleep.
However, a comprehensive cost/benefit analysis would need to take into account various other factors, including the potential benefits of increased alertness and mood during the day, the costs associated with implementing dynamic lighting systems, and the potential long-term health impacts of changes in sleep quality.
8. Our conclusions
Dynamic LED lighting ― a lighting system that varies illuminance and correlated color temperature to approximate natural lighting conditions ― shows some benefits on workers’ alertness during the traditional lull of the afternoon. This is the most positive finding.
However, the prolonged exposure to dynamic LED lighting produces significant effects on the quality of sleep of employees.
This study was not intended to further analyze its findings and their cause. So we don’t know why and how dynamic LED lighting impacts perceived sleep quality, and it is not possible to draw any conclusions in this regard.
LED lighting and dynamic LED lighting are two different things: LED lighting systems have proven benefits in terms of visual comfort in office and retail environments vs. incandescent and fluorescent lighting systems. These systems can be installed without observed downsides. Dynamic LED lighting systems are still experimental, and therefore must be studied more deeply.
Considering the major importance of sleep on long-term health, it would not be prudent to install dynamic LED lighting systems before these findings are studied and clarified, and scientific research establishes more clearly how to use these systems in a way that does not risk people’s well-being.
