Lighting Controls: Achieving Energy Efficiency and Visual Comfort

10/22/2024

Lighting is often overlooked as merely a functional fixture in building design. However, it plays a critical role in shaping both the ambiance and comfort of spaces we live and work in every day. Over the last few decades, the adoption of advanced lighting control strategies has grown to be a powerful tool for both lowering energy consumption and increasing the well-being of its inhabitants. The key is in the design. There is a fine balance and intersection between lighting controls' mandate to lower a building's overall energy consumption and enhance the work/life environment through visual comfort. 

The Energy Efficiency Imperative 

Global energy use is on the rise. As countries further industrialize and depend on a dwindling fossil fuel resource, humanity has an obligation to limit our future energy consumption. Electric lighting, accounting for quite a large portion of energy use in all indoor spaces, presents a great opportunity to help lower our buildings' energy footprint. This is where lighting control design and implementation can offer a varied yet holistic approach to reduce this electrical load. 

As the adoption of LED technology in luminaires has grown, so has the sophistication of the lighting controls available for these sources. Energy codes like the IECC and ASHRAE have been adopted throughout most of the US and have mandated the use of these lighting control strategies within most building types. These lighting controls strategies include occupancy sensing, daylight harvesting, dimming and personal control, and time of day scheduling. Each comes with its own nuances and can play a part in reducing our lighting load. 

Occupancy sensors utilizing infrared, microphonics, or ultrasonic technology detect when we are active in a space and can trigger lighting to be turned on or off. When these devices do not sense activity, they turn off the lights. Over the course of the day, this can lead to a great reduction in energy use. Daylight harvesting adjusts the output of electric light based on available natural light, utilizing the daylight that enters a space to reduce the need for electrical lighting. This strategy can lead to a lower lighting output of a space or eliminate the need for electric lighting all together at times of peak sunlight availability. Dimming and personal control allows for granular light level adjustments within a space. Using dimmers not only optimizes energy consumption by matching lighting output to task requirements but also encourages occupants to adjust light levels to their comfort level, avoiding excessive brightness. Another lighting strategy is time of day scheduling. Many spaces can use a timeclock function to automatically adjust the light outputs throughout the day, depending on when the space is used, and what variation of activities the users participate in. 

Comfort is Key 

In addition to energy savings, additional lighting control designs can positively impact the user's comfort and overall well-being. Balancing the lighting in a space should lead to a well-lit environment that enriches visual clarity, limits eye strain, and gives a sense of safety and security. There are a variety of ways to enrich our spaces for the human experience: personalized lighting, Circadian rhythm response and color temperature exposure, mood enhancement, and visual comfort. These unique concepts can all be utilized to design a human-centric approach. 

As previously discussed, personalized lighting can lower energy consumption. However, we also know that people have unique lighting preferences. This could be based on age, ocular necessity, or just personal taste. Individual lighting controls give us the freedom to customize light levels, color temperature, and even distribution to suit our specific needs and desires. Circadian rhythm support is a newer concept for lighting control that varies the exposure to appropriate light levels and color temperatures at different times of the day to help regulate the body's internal clock, promoting better sleep, alertness, and overall health. Lighting Design can enhance the mood of a space, evoking different emotions and atmospheres for the user. While a dimmed, warm lighting environment creates a relaxing ambiance, a brighter, cooler space stimulates feelings of focus, productivity and security. 

Finally, visual comfort plays a major role in a space. With LED lighting, often the distribution can lead to glare and over-lighting of spaces, so special care needs to be taken in our lighting designs to limit glare inducing eye fatigue and enhance visual comfort. 

A Balanced Approach for Optimal Results 

To achieve both the energy benefits and health benefits of lighting controls, a holistic approach is key. Utilizing these various control technologies and considering the differing characteristics of each space is critical to combine these efforts. Different areas within a building have distinct lighting requirements. For instance, task-oriented spaces like offices demand higher light levels than break rooms or dining areas. Understanding how people use these spaces informs us of the optimal implementation of lighting controls. By checking out use and occupancy patterns, lighting systems can be fine-tuned for both energy efficiency and comfort. Though we must meet the requirements of adopted energy codes, occupant well-being should be the number one priority in our lighting designs. Lighting controls that empower people to personalize their lighting experience contribute to overall health and well-being. 

Lighting controls can be a powerful tool for achieving synchronicity between energy efficiency and personal comfort. By strategically managing our lighting uses, we can significantly minimize energy consumption while enriching spaces that promote well-being and productivity. As both lighting and control technology continues to advance, we can look forward to even more advanced lighting and lighting control systems that will further enhance our journey to lower energy usage and enhance our unique human experience. 

Barry Reeb is a light designer at McClure Engineering, a mechanical and electrical consulting engineering firm dedicated to the development of innovative solutions to unique engineering problems.