The Physiological Effects of Light

At the 12th annual DOE Solid-State Lighting R&D Workshop, held January 27–29 in San Francisco, 300 attendees participated in both plenary and LED/OLED breakout sessions, with presentations from over 60 solid-state lighting experts and special opening remarks from 2014 Nobel Laureate Shuji Nakamura.

One interesting presentation, authored by OSRAM SYLVANIA’s Andreas Wojtysiak, focuses on the physiological impacts of lighting, suggesting that lighting design can have positive impacts. Get it here.


2015 LIGHTFAIR Keynote and Impact Speakers

Notable keynote and impact speakers are a part of the educational experience at 2015 LIGHTFAIR, which will feature 140 presenters during its five-day program May 3-7 in New York’s Javits Center (Pre-Conference LIGHTFAIR Institute: May 3-4; Trade Show & Conference: May 5-7).

Shuji Nakamura, Ph.D. is a 2014 Nobel Prize Winner in Physics and will present “The History of LED Technology to the Nobel Prize to Today’s GaN” during the Pre-Conference Institute Keynote Luncheon on May 3. This address will cover the history of LED technology from his early work which led to the Nobel Prize to today’s GaN which will lead to the next wave of Solid State Lighting. Dr. Nakamura is a professor at University of California Santa Barbara and co-founder of SORAA Inc.

Inventor Chuck Hoberman will speak as the Institute keynote on May 4 about his pioneering work in “Transformable Design” with projects that range from public art to kinetic facades to dynamic sets for live entertainment. His presentation will show how he realizes large-scale transformable structures, and takes his inventive concepts through the stages of engineering, manufacturing and installation. Hoberman is the president and founder of Hoberman Associates in New York. This keynote luncheon is sponsored by COOPER LIGHTING BY EATON, Booth 1157.

As part of the new series “Legends of Lighting,” lighting designer Howard Brandston will be featured as an impact speaker at LFI and interviewed by Chip Israel, founder of Lighting Design Alliance, for an engaging conversation on Brandston’s work and past projects on May 5. Brandston is the founding partner of the Brandston Partnership, a lighting design consulting firm based in New York. He is a past president of the IES and has received over 100 design awards. Brandston has also been an adjunct professor, guest lecturer or visiting professor for over 50 years.

Mark Rea, Ph.D. will outline that great strides have been made to reduce the cost of lighting for general illumination; however, little progress has been made to increase the benefits that lighting provides to society in “Monetizing the Benefits of Lighting” as the Impact Speaker on May 6. Dr. Rea has served as Director since the Lighting Research Center was established in 1988.

Click here to learn more about these presentations.

LED Takes on Fluorescent in Troffers

I wrote this article for the February issue of tED Magazine. Reprinted with permission.

According to the U.S. Department of Energy (DOE), four out of five lamps in service in commercial buildings 2010 were fluorescent, with a majority used in troffer (cross between “trough” and “coffer”) luminaires. Available in standard 1′x4′, 2′x4′ and 2′x2′ sizes, these luminaires are popular in applications featuring dropped acoustical-tile ceilings.

In recent years, LED technology has challenged this venerable workhorse with energy-efficient and long-life alternatives. DOE estimates that energy savings for an individual project can be 25+ percent. Energy savings can be accelerated via operation with automatic lighting controls. With dimming standard or a standard option on a majority of products, integration with controls is more attractive than with fluorescent. And with service life typically rated up to 50,000 hours, owners are promised years of reliable lighting service without changing lamps, reducing maintenance costs.

“The product portfolio for LED recessed troffers and suspended luminaires is broad with a vast variety of options in size, style, optics and color temperatures,” says Eric Stevenson, Product GM, Indoor LED Fixtures, GE Lighting. “Further, the ability to control LED is unsurpassed by other lighting technologies. From occupancy sensors to daylight harvesting and full dimming functionality, end users can enjoy the benefits of a smart, integrated lighting system that can help to further increase energy savings.”

In short, LED general lighting has come a long way in a very short time. DOE estimates the installed base of LED troffers increased from an estimated 40,000 units in 2010 to nearly 700,000 units in 2012. Manufacturers report demand has escalated over the past two years, estimating that 15+ percent of new troffer luminaires sold today employ LEDs as the light source.

“Many of the initial concerns with first-generation technology around light levels, light quality, performance and even cost have been resolved,” says Heather Milcarek, Director, Trade Marketing Professional, Philips Lighting. “For many applications, LED products have become an everyday shelf stock item that the distributor needs to have on hand to avoid losing business to a competitor.”

David VanSpybrook, Director of Sales Enablement, Cree, Inc., agrees: “As LED technology continues to advance, it is important for customers to understand that LED lighting has become viable, high-performing and is ready for mass conversion today. The cost curve and payback period for LED lighting solutions have reached the point where waiting for further advancements actually decreases the potential lifetime savings.”

In recent years, LED technology  has challenged fluorescent for commercial general lighting applications. DOE estimates that energy savings for an individual project can be 25+ percent. Image courtesy of Cree, Inc.

In recent years, LED technology has challenged fluorescent for commercial general lighting applications. DOE estimates that energy savings for an individual project can be 25+ percent. Image courtesy of Cree, Inc.

LED recessed troffers typically operate at a 20 percent higher efficacy than traditional fluorescent systems operating at about 100 lumens/W. Some products have achieved efficacies as high as 150 lumens/W.

While efficacy is important, making LED an economically attractive alternative to fluorescent, the primary consideration is how the LED troffer performs as a lighting product. Manufacturers report that LED troffers are available that provide good light output, color quality and optical control, which is related to both luminaire efficiency and visual comfort. Some products offer color tuning, which is relatively difficult to implement with fluorescent. Others offer advanced onboard digital control and sensors.

“For troffers, there are a lot of products with the LED boards on the back of the housing that push the light directly out,” she says. “It was the quick and efficacious approach. Now we are starting to see more thoughtful designs that aim for that balance of efficacy and visual comfort.”

DOE states that LED troffers are generally comparable in light output to two-lamp troffers, though there are products available that produce light output comparable to three- and four-lamp troffers. Contemporary light level recommendations are lower than when a majority of commercial buildings were built, allowing a reduction in light levels. However, designers must note the service life of the luminaire and associated lumen depreciation to ensure light levels are met on an ongoing basis.

LED troffers are suitable for new construction and retrofit. With nearly 1 billion linear fluorescent luminaires installed in the United States, the existing buildings market is an attractive sales opportunity.

“The proliferation of LED products represents a huge opportunity for electrical distribution,” says VanSpybrook. “The upgrade to LED lighting is a race for contractors and distribution. Who will capture that upgrade opportunity?”

In existing buildings, new LED troffers generally provide higher energy savings for equal luminaire output compared to fluorescent troffers upgraded with LED retrofit kits or replacement lamps, according to DOE. While “drop in” LED linear replacement lamps are available that offer the lowest installation costs, a majority of replacement lamps require electrical modifications with associated installation costs, making new luminaires an economically competitive choice in many cases. For best results, one must note the spacing criterion of any LED option in an existing space to ensure the continuation of good uniformity of light levels across the task plane. Note many LED troffers emit light in a controlled “teardrop” pattern, with some products emitting a small amount of intensity above 60 degrees to place light on high walls and brighten the ceiling plane.

Image courtesy of GE Lighting.

Image courtesy of GE Lighting.

LED is still a young technology and should be viewed cautiously during product selection. Distributors should look for performance that satisfies criteria, backed by testing to industry standards such as IES-LM-79, and strong warranties. It is often desirable to request product samples and encourage a mockup prior to commitment. Distributors should continue to become educated about LED lighting and its suppliers.

“To effectively sell LED products, the distributor sales team must be able to educate the customer about the benefits of the new technology versus traditional lighting options,” says Chris Dolan, Product Marketing, IGA, Philips Lighting. “There is a wide range of performance and quality on the market. Do your homework to determine which product is most appropriate given the performance, aesthetic and budget consideration.”

Stevenson agrees: “It is important to understand the detailed specs and warranties of the lighting you’re purchasing/specifying—you want to make sure you’re aware of the lifespan, engineering and reliability.”

Distributors can find a number of good products among the winners of the Next Generation Luminaires Design Competition ( and the DesignLights Consortium’s (DLC) Qualified Products List (, which is used by many utility incentive programs. The DLC criteria (v.2.1) require: 1) minimum luminaire efficacy of 85 lumens/W, 2) minimum CRI of 80, 3) minimum 50,000-hour rated life (L70), 4) a minimum five-year warranty and 5) minimum light output levels depending on the size of the troffer.

“The biggest benefit to pitch to customers is, ‘LED is going to save you money on reduced energy and maintenance costs,’” Stevenson says. “With performance continually improving and price points becoming even more affordable, the time for LED is now.”

Light and Health: What’s New in Research

The January issue of LD+A included a collection of research projects demonstrating how lighting can impact health. Click here for a quick roundup.

Product Monday: Cycle by Eureka Lighting

Cycle by Eureka Lighting—available in a variety of diameters, mounting methods and color temperatures—produces a glowing halo for large spaces.

Click here
to learn more.




DOE Publishes Long-Term Testing Investigation of Retail Lamps

The U.S. Department of Energy’s CALiPER program has released another special report on LED lamps that are available through the retail marketplace and targeted toward general consumers. CALiPER Retail Lamps Study 3.2 focuses on lumen depreciation and color shift in a subset of 15 LED A lamps from CALiPER Retail Lamps Study 3. The lamps were monitored in an automated long-term test apparatus for more than 7,500 hours.

Ten samples of each lamp were operated continuously at an ambient temperature of 45°C, with measurements recorded weekly. On average, the lumen maintenance of the LED lamps was better than either of the benchmark lamps (CFL and halogen), but there was considerable variation from lamp model to lamp model.

In addition to three observed parametric failures (two from insufficient lumen maintenance and one from excessive color shift), almost half of the products failed to meet ENERGY STAR early-life thresholds for lumen maintenance, which for seven products was sufficiently low at 6,000 hours that they were unlikely to have lumen maintenance above 70% at their rated lifetime (usually 25,000 hours).

DOE’s SSL Program Manager Jim Brodrick comments: “Given the methods used for this investigation, the results should not be interpreted as indicative of a lamp’s performance in a typical environment, nor should they be used to discredit manufacturer lifetime claims. A key takeaway is that the long-term performance of LED lamps can vary greatly from model to model, although the lamp-to-lamp consistency within a given model is relatively good. Further, operation of LED lamps in an enclosed luminaire (or other setting involving high ambient temperatures) can induce parametric failure of LEDs well before their rated lifetime; manufacturer warnings about such conditions should be followed if performance degradation is unacceptable.”

Click here to learn more.

The Industrial Internet and the Future of Lighting

In this short video, GE Lighting President & CEO Maryrose Sylvester discusses the massive transformation underway in the lighting industry as the incandescent lamp is replaced with smart LED systems and cities, companies, and consumers are empowered to cut costs and energy use and improve maintenance and satisfaction.


Architecture for Light Final 12.8.14The Illuminating Engineering Society has published an introductory e-textbook on lighting, ARCHITECTURE FOR LIGHT by Kim and Paul Mercier.

ARCHITECTURE FOR LIGHT is intended for upper level undergraduate or continuing education courses for students of architecture and interior design. The book can also be a resource for architects and interior designers or lighting professionals looking to develop a lighting philosophy. The authors present an intuitive approach to analytical lighting concepts for those who want to learn about lighting but do not necessarily have a scientific background. The intuitive emphasis advances the observation of lighting effects and a design process at an early stage in project development.

Recognizing the need for energy efficiency, the text offers alternative energy design approaches that maximize energy effectiveness of spaces over traditional design methods. Architecture for Light is arranged in un-numbered modules that allow instructors to easily adapt the material to courses of 7 or 13 week duration. Case studies, activities, and projects, plus global examples of art, architecture and manufacturing are included.

Paul Mercier is an instructor at SUNY College at Buffalo and Kim and Paul Mercier have each taught at the University of Calgary Masters of Architecture program. They are also lighting practitioners with their own design firm and are actively involved in the IES.

Click here to learn more and get the book in PDF format at the IES online bookstore.

Lighting Controls Association Publishes 2014 Year in Review and 2015 Construction Forecast

My most recent contribution to the Lighting Controls Association’s blog is a post summarizing current economic trends, 2014 year in review for the lighting industry, and the AIA’s Consensus Construction Forecast.

Check it out here.

Product Monday: SmartCast Intelligent Color Control by Cree

creeCree’s SmartCast lighting control technology now includes field-adjustable color temperature for the company’s SmartCast-enabled CR Series LED troffers. This provides dynamic and customizable color control from 3000K to 5000K in 500K increments for commercial building general lighting.

Click here to learn more.