Benefits of Energy Effective Lighting

Energy Effective Lighting accomplishes the dual objectives of being efficient while meeting the needs of the space occupants. The

U.S. Department of Energy Federal Energy Management Program is committed to saving energy and improving workspaces for

Federal workers at the same time.

When one considers the cost of labor in the workplace compared to the cost of electricity, it

becomes immediately apparent that it is important to consider lighting impacts on the Federal

workforce. In offices alone, the total Federal lighting energy use represents energy costs of about

$170 million per year, while Federal office worker employee costs represent about $70 billion per

year, or over 400 times more.1 Potential productivity improvements are possible if the relighting

is an improvement to the quality of the lighted environment. Considering this within the context

of the Federal energy savings goals, it means that additional benefits should arise out of the

implementation of the presidential executive orders. This provides significant incentive for 

efficiency projects that include relighting. In addition to the environmental and cost benefits of

energy savings, it becomes possible to improve the workplace for Federal workers, resulting in

increased satisfaction and performance.

Proven Opportunities

The theory behind improving productivity with quality lighting is based on the fact that lighting

has a direct and powerful impact on the occupants of buildings. From a conceptual perspective,

it is easy to understand that lighting affects us in many ways, both physically and psychologically. However, many energy managers struggle to separate the anecdotal stories about such 

benefits from reliable and proven opportunities. This flyer provides specific information from

actual research studies, with simple guidance on steps to take in your project work.

Research on Lighting and Productivity

Decades of lighting research have focused on the relationships between task visibility, glare,

comfort, and performance on visual tasks. Only recently have the attributes of light that

influence satisfaction, emotional functioning, and performance on a broad array of 

cognitive and creative tasks been studied. In addition to the studies discussed below,

exciting new research is now under way in the Federal and private sectors. 

GUIDANCE ABOUT

ENERGY EFFECTIVE

LIGHTING

Obtain FEMP Lights products

under the Resources section at

www.eren.doe.gov/femp

1 Read Chapter 3 in the Federal Lighting

Guide to learn more about Energy

Effective Design and Specification.

2 The Energy Effective Lighting Checklist

provides a one-page list of the most

important things to do in your relighting projects.

3 For greater detail that is applicationspecific, review the Energy Effective

Lighting Recommendations for Offices

and Warehouses, found in Appendix 2

of the Federal Lighting Guide.

4 Use lighting design professionals 

for unusual or challenging relighting

projects.

5 Perform a pre- and post-occupancy

survey to quantify the satisfaction 

of Federal workers. For standardized

survey tools, contact Carol.Jones@pnl.gov.

6 Contact FEMP to obtain technical 

support for challenging or unusual

applications.

“At the Department of State we’ve learned from experience

that our employees feel strongly about having good 

lighting, and that lighting can help our people accomplish

their missions. Energy and cost savings along with improved

environments give us the best of both worlds.”

Richard Tim Arthurs, Energy Policy and Conservation Officer

Office of Facilities Management Services, U.S. State Department

Room Surface Brightness

The overall brightness of a room is greatly influenced by the 

luminance of vertical surfaces, including walls as well as cubicle

partitions. In general, people prefer well-lighted walls to dark ones,

so long as the wall is not so bright that it becomes a secondary

glare source. Although worker satisfaction is valuable in its own

right, there is some preliminary indication that satisfaction and

improved moods (positive emotional functioning) also may impact

task performance and motivation.2

■ Numerous studies have shown that satisfaction is higher in spaces with

vertical surface lighting — such as that from wall washers and wall

sconces, or ceiling light that spills over onto the walls.3,4,5

■ Dissatisfaction with dark walls may result from perceptions of gloominess. Researchers suggest that gloom is psychologically undesirable

because it is associated with reduced peripheral vision and thus serves as

a primitive warning system that visual acuity is being compromised.6

■ Wall washers and sconces also add a sense of visual interest that is 

associated with increased ratings of lighting quality.7

■ Another mitigating factor is the nature of the task: people prefer lower

wall brightness for computer tasks and higher brightness for reading or

writing. Similar results were found in a study of workstation lighting.8

BENEFICIAL ASPECTS OF LIGHTING

circadian rhythm: a self-sustained biological rhythm 

which in an organism’s natural environment normally 

has a period of approximately 24 hours.

luminaire: a light fixture; a complete lighting unit consisting 

of a lamp or lamps and ballast(s) (when applicable) together

with the parts designed to distribute the light, to position 

and protect the lamps, and to connect the lamps to the 

power supply.

visual acuity: a measure of the ability to distinguish fine details.

“The more we come to understand about lighting the more we

appreciate it’s importance. Lighting projects present a significant

opportunity for us to add value to our facilities and improve the

workplace.”

James Woods, Energy Conservation Officer

U.S. Department of Commerce
Personal Control

It has long been known that individuals vary enormously in preferred lighting. Yet there

has been little effort to develop lighting technologies and systems that allow for 

individual control, in part because building managers believe that personal control will

lead to increased energy consumption. With greater personal control over lighting at the 

workstation, individuals can choose light levels consistent with their general preferences

and can vary light to fit their specific tasks. 

■ A recent study at the National Research Council Canada shows that the ability to control 

lighting has positive impacts on workers’ mood and satisfaction, and also leads to high ratings

of lighting quality.9 The Canadian study also found that the lighting choices were well within

current energy code limits for office lighting. 

■ A laboratory study at Rensselaer Polytechnic Institute’s Lighting Research Center found that 

subjects who had dimmable ceiling light adjusted it throughout the experimental conditions as

tasks changed.10 Further, subjects who had the controllable lighting were more satisfied with

the lighting, felt more comfortable in the room, rated the tasks as less difficult, and rated the

lighting quality as higher than subjects who did not have control. Importantly, having the 

control system produced a 35% to 42% decrease in electrical consumption.

Overhead and Reflected Glare

Glare from ceiling lights can be a problem if it produces reflections on the computer

screen that interfere with task visibility. In addition, new research indicates that bright

luminaires located overhead can create visual discomfort.

■ A significant problem in many offices is the reflection of lumminaires in visual display terminal

(VDT) screens.11 Lensed fixtures are more problematic than most other fixture types. A new

study shows that reflected glare from bright luminaires in the ceiling plane is reduced 

significantly if the highest-quality VDT screens are used.12

■ An experimental workshop was held by the joint committees of two professional lighting 

associations* to study the phenomenon of overhead glare. The results obtained demonstrate

that a significant number of people do experience discomfort from a high-luminance luminaire 

overhead, even when the fixtures are at the edge of the field of view or just outside the field 

of view.13

Other Lighting Aspects

In addition to the categories listed above, numerous other aspects of lighting are being

studied. The impacts are profound, ranging from visual fatigue to important physical

and psychological health effects.

■ There is an indication from a number of researchers that headaches are reduced when electronic 

ballasts are used rather than magnetic.14

■ An extensive review of lighting and health15 shows that bright light affects circadian rhythms

and seasonal depression. However, the lighting levels necessary to positively influence physiology and well being are much higher than lighting in typical office settings. Thus, interior light

is not expected to influence circadian systems. An exception is shift work where bright light is

being used to reduce fatigue, increase alertness, and improve cognitive functioning in night

workers.

■ It is widely understood that most people prefer daylighting and often desire access to a view in

most types of work setings.16 A recent study found that improved student performance is 

positively associated with more daylight in schools. There is reason to believe that benefits from

daylighting can be translated to other building types and human activities.17

■ Lamps that are high to very high in color temperature (5,000K to 7,500K) provide improved 

visual acuity compared to lower-color temperature lamps (typically 3500K) at the same light

level. High-color temperature lamps are rich in the blue portion of the color spectrum and have

a noticeably “cool” appearance. For applications where it is appropriate to use lamps with 

this color appearance, one can produce similar visual performance with fewer measured 

footcandles and less energy consumption.18

■ Although numerous claims have been made about the benefits of “full-spectrum” light, there

is no convincing evidence at the present time about differential health benefits associated with

spectral characteristics.19

REFERENCES

1 Harris, L. et.al, 1998. Potential productivity 

benefits from high quality lighting in Federal 

buildings. Proceedings of 1998 ACEEE Summer Study

on Energy Efficiency in Buildings. American Council

for an Energy-Efficient Economy, Washington, D.C.

2 Veitch, J. 2000. Psychological processes 

influencing lighting quality. Accepted for publication,

Journal of the illuminating Engineering Society of

North America, 19-20. National Research Council

Canada. 

3 Sanders, P.A. and Collins, B.L. 1996. Postoccupancy evaluation of the Forrestal Building.

Journal of the Illuminating Engineering Society,

Summer: 89-103.

4 Collins, B., Fisher, W.S., Gillette, G.L., and

Marans, R.W. 1990. Second level post occupancy

evaluation analysis. Journal of the Illuminating

Engineering Society, Summer: 21-44.

5 van Ooyen, M.H.F., van de Weijgert, J.A.C., 

and Begemann, S.H.A. 1987. Preferred illuminances

in offices. Journal of the Illuminating Engineering

Society, 16: 152-156.

6 Shepherd , A.J., Julian, W.G., Purcell, A.T. 1992.

Measuring appearance: parameters indicated from

gloom studies. Lighting Research and Technology.

24(4): 203-214.

7 Hawkes, R.J., Loe, D.L., and Rowlands, E. 1979.

A note towards the understanding of lighting quality.

Journal of the Illuminating Engineering Society,

January: 111-120.

8 Bernecker, C., Davis, R.G., Webster, J.P. 1993.

Task lighting in the open office: a visual comfort 

perspective. Journal of the Illuminating Engineering

Society, Winter: 18-25.

9 Newsham, G. and Veitch, J. 2000. A new

method of deriving illuminance recommendations 

for VDT offices. IESNA Proceedings 2000 Annual

Conference.

10 Boyce, P.R., Eklund, N.H. and Simpson, S. N.,

2000. Individual lighting control: task performance,

mood and illuminance. Journal of the Illuminating

Engineering Society, Winter: 131-142.

11 Kohn, M.B. 1989. VDT Lighting – IES

Recommended Practice for Lighting Offices

Containing Computer Visual Display Terminals.

Illuminating Engineering Society of North America.

12 Miller, N., Boyce, P., and Ngai, P. 2000. A 

metric for judging acceptability of direct luminaires 

in computer offices. IESNA Proceedings 2000 Annual

Conference.

13 Ngai, P. and Boyce, P. 1999. The effect 

of overhead glare on visual discomfort. IESNA

Proceedings 1999 Annual Conference.

14 Wilkins, A.J., Nimmo-Smith, I., Slater, A., and

Bedocs, L. 1989. Fluorescent lighting, headaches and

eyestrain. Lighting Research and Technology, 21 (1):

11-18.

15 Salares, V. 1996. Lighting and human health: 

a review of the literature. Canada Mortgage and

Housing Corporation Report.

16 Collins, B.L. 1975. Windows and People: A 

Literature Survey. NBS BSS 70, National Bureau of

Standards, Washington D.C.

17 Heschong Mahone Group. 1999. Daylighting 

in Schools – An Investigation into the Relationship

Between Daylighting and Human Performance.

Pacific Gas and Electric Company. Available online at

www.pge.com

18 Berman, S.M. 1992. Energy efficiency consequences of scotopic sensitivity. Journal of the

Illuminating Engineering Society, Winter 1992.

19 Veitch, J.A. and McColl. 1994. Full-spectrum

fluorescent lighting effects on people: a critical

review. In J.A. Veitch (Ed.) Full-spectrum lighting

effects on performance, mood, and health. 

(IRC-IR-659, pp 53-11). National Research Council

Canada, Institute for Research in Construction.

Ottawa, ON.

C Printed with soy ink on recycled paper.

* The workshops were held by the Illuminating Engineering Society’s Quality of the Visual Environment

Committee and the International Association of Lighting Designers Metrics of Quality Committee.

TECHNICAL QUESTIONS?

Send email to Carol.Jones@pnl.gov