Ergonomics may be defined as the art and science of designing workplaces, products, processes,and environments to improve human performance and well-being (i.e., comfort, health, safety, happiness, job satisfaction, etc.). In this context “good lighting” is lighting that enhances employee productivity and reduces stress by making tasks easier to perform. Good lighting also creates a pleasant working environment. This improves employee job satisfaction, reduces absenteeism, and increases employee retention.
What are the effects of bad lighting?
“Bad lighting” is lighting that is inappropriate for the tasks being performed. The level of illumination may be too low or too high, excessive direct or reflected glare may be present, thecolor rendering of artificial light sources may be inadequate, or the distribution of light may be inappropriate.
Poor lighting has been associated with a variety of problems including low productivity, high human error rates, eye strain, headache, a reduction in mental alertness, general malaise, and low employee morale. Each of these problems can have a significant negative economic impact onany business organization. Poor lighting may also cause employees to assume awkward body postures, which may contribute to the development of cumulative trauma disorders (CTDs) suchas carpal tunnel syndrome.
What economic benefits can businesses expect if they improve workplace lighting?
The answer to this question depends on the type of work being performed at the workplace and the specific improvements that will be made. Some of the direct and indirect economic benefits that businesses might realize are:
- a direct reduction in lighting costs
- an increase in employee productivity
- an improvement in employee well-being that usually reduces absenteeism and improves employee retention
Each of these outcomes is discussed below.
Direct reductions in energy costs for lighting
An economic benefit sometimes associated with workplace lighting improvements is a reductionin energy costs. Several approaches have been used to achieve this benefit.One way to improve workplace lighting and to decrease lighting costs at the same time is toreduce overall illumination from artificial light sources when it is too high. This reduction maybe accomplished by replacing existing lamps with lamps having a lower lumen output and by removing lamps that are not needed. Lighting costs will be significantly reduced, and employee productivity may increase as well.
Another strategy for improving workplace lighting that also reduces operating costs is to increaseuse of natural light by installing skylights and making other modifications to facilities. This greatly reduces the amount of light required from artificial sources. Another advantage of usingdaylight is that it illuminates walls and ceilings to create a more natural-appearing workspace.The Lockheed plant in Seattle, WA has been successfully modified to utilize daylight as a majorsource for lighting. Annual lighting costs were reduced by $500,000, and employee productivity increased by 15%. The latter economic benefit is attributable, in part, to an increase in the quality of lighting.
A somewhat unconventional approach that also achieves both lighting cost reductions and animprovement in workplace lighting has been successfully implemented at Intel Corporation. At one plant conventional lamps were replaced with lamps having a lower lumen output but better color rendering. The improvement in color rendering (i.e., lighting quality) completely offset the effects of the reduction in illumination. As expected, annual lighting costs were significantly reduced. Other reported benefits included a reduction in glare and eye strain and improvements in employee perceptions of the work environment.
Better employee productivity
A second economic benefit often associated with lighting improvements is better employee productivity. The increase in productivity at the Lockheed plant in Seattle (discussed above) isone good example. Another is a 16% improvement in productivity at a West Bend Mutual Insurance facility attributable to a lighting upgrade.
Lighting improvement projects often do not improve productivity as dramatically as in the Lockheed and West Bend Mutual Insurance examples described above. One reason is that numerous factors other than lighting also affect productivity. Personal factors such as one’s relationship with the boss, problems at home, the car breaking down, bills, and lack of sleep can have a profound negative effect on productivity. When present, these factors may offset the beneficial effects due to lighting improvements.
Another reason that productivity improvements associated with lighting changes may be underestimated may be attributable to the way some researchers measure productivity. By focusing on performance over relatively short periods of time, longer term effects may not be noticed. Consider a recent study conducted by researchers from the Lighting Research Center at Rensselaer Polytechnic Institute. In this study workers performed data entry tasks while sitting at a computer. Some monitors had reflections (a form of reflected glare) while others did not.The reflections were annoying but did not mask critical information needed to complete the tasks. Work time (how long it took a worker to complete a single data entry task) was about thesame regardless of the lighting conditions. However, workers at monitors with reflections took longer rest periods between tasks. The researchers estimated that the loss in productivity due tothe longer breaks was about 80 minutes per week. At $10/hr this adds up to a loss inproductivity of about $650 per year per employee that could be recovered by making lighting improvements.
Improvement in employee well-being
A third benefit frequently associated with lighting upgrades is an improvement in employee well-being, which often leads to a reduction in absenteeism and employee turnover. “Employee well-being” in this context refers to the overall quality of working life in general but more specifically to job satisfaction.
Lighting affects our subjective impressions of our working environment, which ultimately affect our behavior and job satisfaction. Relationships between lighting and subjective impressionswere clearly established in a well-known series of studies by John Flynn at Pennsylvania State University during the 1970s. Flynn varied the type, amount, and distribution of light in conference rooms and measured subjective impressions of visual clarity, spaciousness, relaxation, privacy, and overall pleasantness. Flynn found that rooms with a combination of lighting on the table and walls were perceived as being pleasant, relaxed, interesting, and likeable. Rooms that provided illumination only on the table were perceived as being small and cramped, whereas those with both wall and table lighting or wall lighting alone were perceived as being larger and more spacious. Later studies showed that certain types of lighting contributed to anxiety, stress, and depression.
Good lighting not only helps us to perform better, it also helps us to feel better. However, in order to achieve both benefits the designer must understand how lighting affects both visual and non-visual behavior. The goal is to create a pleasant working environment – one that peopleenjoy being in and want to return to – where people can work effectively. Only by applying a holistic approach can optimum results be obtained.An investment in workplace lighting improvements often has positive economic benefits. Among the economic benefits that may be realized are direct reductions in energy costs for lighting and better employee productivity. An indirect benefit, often attained, is an improvement in employee well-being, which may reduce absenteeism and improve employee retention.