Lighting Strategies - New Study Explores Lighting & Productivity Link

Dec. 30, 2003
Lighting is a productivity tool.

Consider productivity as the proverbial "widgets per hour." Workers need varying amounts of light depending on what type of work they're doing and how old they are. When there is enough light, the lighting is supporting them being able to perform tasks efficiently and accurately. When there is insufficient light, the opposite happens, which affects productivity. If the construction team did its job right, sufficient light is being provided in your building (although it is always a good idea to survey occupants about what they think of the lighting and make improvements to ensure they have enough light to do their jobs and are not being affected by glare). The only thing you have to worry about is maintenance, making sure the lights are working properly and are quickly replaced upon failure.

The problem is that productivity is not just widgets per hour. In the modern office in a service industry, the productivity picture includes a range of metrics. Worker satisfaction and motivation, for example, are important metrics - much more so now than they were years ago.

Consider a study in the Journal of Occupational Health Psychology, which reported that job satisfaction accounted for 63 percent of variance in organization commitment, which accounted for 80-percent variance in intent to turnover. In that study, job satisfaction incorporated satisfaction with the physical environment. A 1987 study in the Journal of Applied Psychology reported that workplace characteristics accounted for a 31-percent variance in work satisfaction.

Can lighting be used to increase worker satisfaction and motivation and thereby increase productivity? Experts say yes, but now we are going beyond the engineering side of lighting - putting footcandles on a work surface-where everything boils down to math. We must instead look at how the light is distributed, and where it ends up. It gets trickier here-proving the benefit, and demonstrating the right way to light a space. But with the possible benefits being so strong, building owners and managers are wise to investigate their options and take the issue seriously. The lights in a modern office may be out of the way, but we use them to see everything-from the marble floor in the lobby to the carpet to the tasks we perform. How a space is lighted shapes our perception of everything we see.

The important thing to remember is that occupants want good lighting and consider it to be very important. Consider the results of several studies:

An American Society of Interior Designers (ASID) study determined that 68 percent of employees complain about the light in their offices.The 1989 Steelcase Office Environment Index (Louis Harris) showed that workers consider eye strain to be the leading hazard to their health in the office.A Silicon Valley study found that 79 percent of computer users would like better lighting. In this article, we will talk about the relationship between lighting and productivity, and then unveil the results of a new study that indicates a causal relationship between certain types of lighting and higher worker motivation and satisfaction. Finally, after long research by the lighting industry, there is growing evidence that not only is lighting important, but how a space is lighted can affect how satisfied workers are with their workplace.

Facing The Barriers
While building owners and managers may be interested in better lighting, they may not actually choose to install it unless they believe that it can be measurably beneficial for their workforce. The three (interrelated) barriers to adoption of quality lighting are initial cost, a lack of scientific evidence of the link between lighting quality and human performance, and the ability to predict financial benefits of increases in occupant satisfaction.

Over the years, you have probably heard some of the anecdotal evidence:
Lockheed saved $500,000 per year in energy costs during a lighting upgrade in an engineering and development facility. The upgrade, however, also resulted in a 15 percent increase in productivity and a 15 percent decrease in absenteeism, as reported in Solar Today, May/June 1995.West Bend Mutual Insurance reduced energy costs by 40 percent with a lighting upgrade, while increasing productivity in the claims processing department by 16 percent, as reported by the National Lighting Bureau.Wal-Mart's Eco-Mart store saw sales become "significantly higher" on the half of the store lighted by skylights versus the half lighted by electric lighting, as reported in The Wall Street Journal, November 20, 1995.In 1986, the main U.S. post office in Reno, Nevada was upgraded, with a causal relationship demonstrated to subsequent productivity gains by mail sorters and operates of mechanized sorting machines, according to the Rocky Mountain Institute. Mail sorters became the most productive in the western region of the United States (from Colorado to Hawaii), while operators of the post office's mechanized sorting machines gained the lowest error rate. While the energy and maintenance savings amounted to about $50,000 per year, the productivity gains were anticipated to generate between $400,000 and $500,000 per year.Compelling, but not scientific enough for some decision-makers. They wanted the "missing link"-scientific evidence demonstrating a causal link between lighting quality and worker performance.

The lighting industry responded to this need by forming the Light Right Consortium in partnership with the U.S. Department of Energy, which just completed a landmark study of the causal link between worker performance and lighting. First they conducted market research and found:
75 percent of decision-makers said that if factual evidence were available indicating a positive effect by lighting on worker productivity, it would influence what lighting systems they would buy.87 percent of decision-makers reported flexibility in lighting budgets if a return on investment could be demonstrated.Respondents reported employee/occupant satisfaction to be even more important than worker output, retention and absenteeism, which gave the Consortium indications on where to focus their efforts.The owner does not consider lighting quality to be very important, particularly in tenant-occupied buildings.The building manager considers lighting quality to be very important.Proving the Link: Light Right Consortium Study
The Light Right Consortium next set up a research study to address the question, "Can different forms of realistic office lighting affect the performance of office work or the well-being of employees?" The primary variables to be studied included room surface brightness and personal control. It was set up as a field simulation, conducted in the field but with simulated tasks and a high degree of experimental control that is typical of laboratory studies-this approach being taken to maximize realism and validity of the results. In an office in Albany, NY, temporary workers were studied performing a range of office tasks under six lighting conditions.
Based on the study's findings, these conclusions can be drawn:Direct/indirect fixtures with perimeter wall washing is considered more "comfortable" and less "uncomfortably bright" than lensed and parabolic troffers,About 70 percent of occupants considered lensed and parabolic to be "comfortable" overall versus 81-85 percent for direct/indirect with wall washers and 91 percent for the personal dimming control condition. A higher percentage of the population prefers light on the ceiling and walls.People with personal dimming control showed more sustained motivation and improved performance on a measure of attention. They also reported higher ratings of lighting quality, overall environmental satisfaction and self-rated productivity.People who are more satisfied with their lighting rate the space as more attractive, are happier, and are more comfortable and satisfied with their environment and their work.Lighting and task conditions that improve visibility lead to better task performance.While putting light on ceilings and walls was found to be an important factor, personal dimming control emerged as the biggest star of the study. Occupants were allowed to dim the direct component of the direct/indirect fixture over their workstations using their PC. This not only made the workers more satisfied, but also resulted in increased motivation throughout the day-a primary productivity metric. In addition, personal dimming control results in cumulative energy savings that can be significant.

The next challenge for the Light Right Consortium is to run a field study where these questions are investigated in an actual workplace and organizational productivity metrics can be collected.

After the full field study, which is anticipated to begin in 2004, the next step for the Light Right Consortium is to develop tools-such as lighting analysis software that integrates potential productivity benefits with energy savings to create a life-cycle cost analysis for various lighting approaches being considered for projects.

For more information about the study, click here to see the chart or visit

Send your feedback to Craig DiLouie at [email protected].

Next issue of Lighting Strategies: Energy savings with new Super T8 lighting systems.

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