Below is my contribution to the May 2019 issue of tED Magazine, the official publication of the NAED. Reprinted with permission.
For a decade, the lighting industry focused on increasing LED source efficacy (lumens/W), resulting in today’s highly efficacious and compact luminaires. As efficacy reaches an economically practical limit, the conversation is changing to emphasize “quality lighting” and its value. While it’s a longstanding, venerable concept in lighting, the LED revolution provides new tools for its realization, though these tools add to lighting’s complexity and thereby require education for proper implementation.
First, it’d be a good idea to define exactly what quality lighting is. It can be defined as lighting that satisfies users and owner requirements, often going beyond watts and footcandles to address issues such as visual comfort, object and space perception, color, and more. It is lighting that accomplishes satisfaction through design best practices and metrics. And it is lighting that relies on quality products—good color, optics, aesthetics, stable light output, etc.—to deliver on these goals.
“Quality lighting is the result of a holistic process,” said Michael Thornton, CMO, Focal Point. “It involves lighting design, quality luminaires, quality light sources and optical delivery systems, installation, and integration with controls.”
Benefits of quality lighting vary by application and owner project goals. Thornton boiled them down: “Inviting spaces that appear comfortable, increased well-being of occupants, mood-setting, enhanced architecture, and support of good visual acuity, and increased productivity.”
Nishad Chikhliker, Segment and Commercialization Marketing Manager, Connected Buildings, Eaton’s Lighting Division, said the concept of quality lighting is expanding due to new tools offered by LED lighting, such as intensity and color tuning and the ability to collect data. “I define quality lighting as connected lighting that leverages the real estate of the physical light fixture to increase operating efficiency through controls and data,” he said. “It goes beyond controlling lights—it’s also solving higher-complexity problems enabled by sensing and communication capabilities within the light fixture itself.”
These benefits are more difficult to quantify than energy savings, though the potential value is far greater, and one an educated customer may appreciate. Industry experts are talking up the $3 (utilities)/$30 (real estate)/$300 (employee wages and benefits) formula, which breaks down a rule of thumb cost of operating one square foot of commercial building space. One might add $3,000 or some multiplier thereof to include the output of all this, which is revenue. Looking at this formula, one can understand how a small impact on the 30/300/3000 side can result in far greater economic gains than a big impact on the 3.
Approaches
“Light quality is very subjective by nature,” said Brian Vedder, Product Marketing Manager, Signify. “However, there are several light characteristics that are universal. Even though personal preferences can’t be altered, a degree of standardization and criteria for light quality should be made to give distributors the tools necessary to help their customers identify and obtain the right product for the right application.”
He said the top five attributes of a quality lighting design are light source spectral emission (color spectrum), minimization of flicker, properly tuned light levels, and reliable product performance and longevity.
“Quality is hard to define, and it is an ongoing challenge,” Vedder added. “When two lights shine side by side, customers will choose what they perceive to be the best lighting for their needs. Distributors need to consider working with lighting experts who have the deep expertise to properly pair the right LED lighting to their application. This can prove to be invaluable for potential product sales, especially as LEDs become more affordable and as they become the most reliable, durable, and color-consistent source of lighting over traditional sources.”
One way to address the subjective nature of what quality means to users is to ask them about their preferences. In 2012, the Light Right Consortium published an online survey tool available to the industry, available for free on the Department of Energy’s website at https://bit.ly/2L2dYOR. Aimed at users, this 50-question survey can be used to provide a detailed view of user perceptions about their lighting. This can facilitate identifying problems and solutions that are more precisely tuned to user preferences.
Another approach is to attempt to develop metrics that practitioners can use to more objectively evaluate and envision lighting quality. Various metrics are available that cover everything from light intensity to color performance, while some metrics are evolving to address the characteristics of LED sources. The predominant focus on light level over distribution of light intensity led designer and educator Christopher Cuttle to propose new metrics focusing on human responses to the visible effects of lighting. It remains to be seen whether the idea, which would empower practitioners like distributors to approach lighting design at a higher level, will catch on.
Chikhliker offered a quality lighting list with a broader emphasis, including optimal light distribution, superior visual comfort, high efficiency, the right aesthetics, and connected lighting capabilities.
“Benefits include soft natural light, energy savings, and architectural aesthetics that don’t draw undue attention to the ceiling,” he said. “You want lighting that is aesthetically pleasing while blending into the environment. Additional benefits with connected lighting include occupancy sensing, daylight harvesting, space utilization, asset tracking, and energy code compliance.”
Thornton said recent research into “humancentric” lighting, conducted by organizations such as the Pacific Northwest National Laboratory (PNNL) and Penn State University (PSU), provides a framework for what quality of light appeals to the majority of human beings, and it’s focused on light’s rendition of colors in a space. “In broad terms,” he said, “preference can be defined as a combination of fidelity and red saturation.”
In other words, good color rendering with an emphasis on a richer rendition of reds. Thornton added the most recent WELL Building Standard’s Electric Light Quality feature (L07) requires light sources feature an average fidelity rating (Rf, as defined in the Illuminating Engineering Society’s 2015 TM-30 color evaluation method) of at least 78 and an average color saturation rating (Rg) of at least 100.
“LEDs have created a greater opportunity to address light quality,” Thornton pointed out. “Quality lighting leverages this technology to provide options that address consumer needs, rather than simply provide illumination.”
Quality by design
While quality lighting is experiencing a resurgence in popularity as a concept, it remains as ever subjective and difficult to define. It can be boiled down to several simple maxims: listen to the customer about their lighting needs, educate the customer about what their lighting can do for them, educate yourself to properly match the right light to the application (including the latest research into human preferences related to light), and qualify products to ensure they have the right characteristics for the job.
