Energy Savings Estimates of Light Emitting Diodes
 

in Niche Lighting Applications
 

Prepared for:
 

Building Technologies Program
 

Office of Energy Efficiency and Renewable Energy
 

U.S. Department of Energy
 

Prepared by:
 

Navigant Consulting Inc.
 

1801 K Street, NW Suite 500
 

Washington DC, 20006
 

Released: September 2008
 

Revised: October 2008
 

 

 

 

 

Energy Savings Estimates of Light Emitting Diodes 

in Niche Lighting Applications 

Prepared for:
 

Building Technologies Program
 

Office of Energy Efficiency and Renewable Energy
 

U.S. Department of Energy
 

Prepared by: 

Navigant Consulting Inc. 

1801 K Street, NW Suite 500 

Washington DC, 20006 

Released: September 2008
 

Revised: October 2008
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Disclaimer 

This report was prepared as an account of work sponsored by an agency of the United States 

Government. Neither the United States Government, nor any agency thereof, nor any of their 

employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, 

express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, 

or usefulness of any information, apparatus, product, or process disclosed, or represents that its 

use would not infringe privately owned rights. Reference herein to any specific commercial 

product, process, or service by trade name, trademark, manufacturer, or otherwise, does not 

necessarily constitute or imply its endorsement, recommendation, or favoring by the United 

States Government or any agency, contractor, or subcontractor thereof. The views and opinions 

of authors expressed herein do not necessarily state or reflect those of the United States 

Government or any agency thereof. 

Copies of this Report 

Electronic (PDF) copies of this report are available to the public from: 

National Technical Information Service (NTIS) 

U.S. Department of Commerce
 

5285 Port Royal Road
 

Springfield, VA 22161
 

Tel: 1-800-553-6847
 

Web: www.ntis.gov
 

Building Technologies Program 

U.S. Department of Energy 

Web: http://www.eere.energy.gov/buildings/info/publications.html#technicalreports 

i 
 

 

 

 

 

 

 

 

 

 

 

 -0121

Foreword 

This analysis of niche markets and applications for light emitting diodes (LEDs) was undertaken 

on behalf of the U.S. Department of Energy to develop a more complete understanding of the 

energy savings resulting from the use of LEDs and the factors that are motivating consumers to 

adopt this new technology. 

Comments 

The Department is interested in receiving input on the material presented in this report. If you 

have suggestions of better data sources and/or comments on the findings presented in this report, 

please submit your feedback to Dr. James R. Brodrick by November 30, 2008 at the following 

address: 

James R. Brodrick, Ph.D.
 

Program Manager – Lighting Research and Development
 

EE-2J / Forrestal Building
 

U.S. Department of Energy
 

1000 Independence Avenue SW
 

Washington, D.C. 20585
 

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Acknowledgments 

The authors would like to acknowledge the valuable support, guidance, and input offered in the 

preparation of this report. James R. Brodrick, Ph.D., of the U.S. Department of Energy, Building 

Technologies Program provided oversight of the assignment, helping to shape the approach, 

execution, and documentation. The authors are also grateful to the following list of experts for 

their respective contributions, guidance, and review, which proved invaluable in preparing the 

estimates contained in this report. 

David Allen Forever Bright 

Steven Altamura Seasonal Specialties 

Vrinda Bhandarkar Strategies Unlimited 

Jill Bonilla SloanLED 

Jose Chavez Westinghouse – Lighting Technologies 

Kevin Dowling Philips Lighting Company 

Gary Durgin Dialight 

Cheryl English Acuity Brands Lighting 

Raj Ghaman Federal Highway Administration 

Kelly Gordon Pacific Northwest National Laboratory 

Daniel Howe City of Raleigh 

Damon Jackson LEDTronics 

Greg Merritt CREE 

Greg Mueller Beta Lighting 

Brian Owen greenTBiz – LEDs MAGAZINE 

Mia Paget Pacific Northwest National Laboratory 

Jim Sloan SloanLED 

Robert Steele Strategies Unlimited 

Wade Swormstedt Signs of the Times 

J. Bryan Vincent AgiLight 

Fred Welsh Radcliffe Advisors 

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TABLE OF CONTENTS
 

1. INTRODUCTION .............................................................................................................1
 

1.1. LED TECHNOLOGY BACKGROUND ............................................................................... 1
 

1.2. NICHE MARKETS REVIEWED ........................................................................................ 2
 

1.3. ESTIMATED NATIONAL ENERGY CONSUMPTION METHODOLOGY................................... 3
 

1.4. TECHNOLOGY BENEFITS IN ADDITION TO ENERGY SAVINGS.......................................... 5
 

2. COLORED-LIGHT APPLICATIONS ..........................................................................11
 

2.1. TRAFFIC SIGNALS AND PEDESTRIAN CROSSINGS ......................................................... 11
 

2.1.1. Introduction....................................................................................................... 11
 

2.1.2. Traffic Signal and Pedestrian Crossing Installed Base........................................ 13
 

2.1.3. Traffic Signal and Pedestrian Crossing Operating Hours.................................... 13
 

2.1.4. Traffic Signal and Pedestrian Crossing Lamp Average Wattages ....................... 14
 

2.1.5. Traffic Signal and Pedestrian Crossing Energy Saving Potential........................ 15
 

2.1.6. Technology Benefits in Addition to Energy Savings.......................................... 17
 

2.2. DECORATIVE HOLIDAY LIGHTS .................................................................................. 17
 

2.2.1. Introduction....................................................................................................... 17
 

2.2.2. Decorative Holiday Lights Installed Base and Operating Hours......................... 18
 

2.2.3. Decorative Holiday Lights Energy Saving Potential .......................................... 19
 

2.2.4. Technology Benefits in Addition to Energy Savings.......................................... 21
 

2.3. EXIT SIGNS ................................................................................................................ 21
 

2.3.1. Introduction....................................................................................................... 21
 

2.3.2. Exit Signs Installed Base ................................................................................... 22
 

2.3.3. Exit Signs Operating Hours ............................................................................... 23
 

2.3.4. Exit Signs Lamp Average Wattages................................................................... 23
 

2.3.5. Exit Signs Energy Saving Potential.................................................................... 24
 

2.3.6. Technology Benefits in Addition to Energy Savings.......................................... 25
 

2.4. ELECTRIC SIGNAGE .................................................................................................... 25
 

2.4.1. Introduction....................................................................................................... 25
 

2.4.2. Electric Signage Installed Base, Operating Hours, Wattage ............................... 26
 

2.4.3. Electric Signage Energy Saving Potential .......................................................... 28
 

2.4.4. Technology Benefits in Addition to Energy Savings.......................................... 29
 

3. INDOOR WHITE-LIGHT APPLICATIONS................................................................30
 

3.1. RECESSED DOWNLIGHTS ............................................................................................ 30
 

3.1.1. Introduction....................................................................................................... 31
 

3.1.2. Recessed Downlights Installed Base .................................................................. 32
 

3.1.3. Recessed Downlights Operating Hours.............................................................. 33
 

3.1.4. Recessed Downlight Lamp Average Wattages................................................... 34
 

3.1.5. Recessed Downlights Energy Saving Potential .................................................. 34
 

3.1.6. Technology Benefits in Addition to Energy Savings.......................................... 35
 

3.2. REFRIGERATED DISPLAY CASES ................................................................................. 35
 

3.2.1. Introduction....................................................................................................... 35
 

3.2.2. Refrigerated Display Cases Installed Base ......................................................... 37
 

3.2.3. Refrigerated Display Cases Operating Hours ..................................................... 38
 

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3.2.4. Refrigerated Display Cases Lamp and Ballast/Driver Average Wattages ........... 38
 

3.2.5. Refrigerated Display Cases Energy Saving Potential ......................................... 38
 

3.2.6. Technology Benefits in Addition to Energy Savings.......................................... 39
 

3.3. RETAIL DISPLAY ........................................................................................................ 39
 

3.3.1. Introduction....................................................................................................... 39
 

3.3.2. Retail Display Installed Base ............................................................................. 41
 

3.3.3. Retail Display Operating Hours......................................................................... 42
 

3.3.4. Retail Display System Average Wattages .......................................................... 42
 

3.3.5. Retail Display Energy Saving Potential ............................................................. 43
 

3.3.6. Technology Benefits in Addition to Energy Savings.......................................... 44
 

3.4. TASK LIGHTING ......................................................................................................... 44
 

3.4.1. Introduction....................................................................................................... 44
 

3.4.2. Task Lighting Installed Base.............................................................................. 46
 

3.4.3. Task Lighting Operating Hours ......................................................................... 47
 

3.4.4. Task Lighting Lamp Average Wattages............................................................. 48
 

3.4.5. Task Lighting Energy Saving Potential.............................................................. 49
 

3.4.6. Technology Benefits in Addition to Energy Savings.......................................... 49
 

3.5. OFFICE UNDERSHELF LIGHTING.................................................................................. 50
 

3.5.1. Introduction....................................................................................................... 50
 

3.5.2. Office Undershelf Lighting Installed Base ......................................................... 51
 

3.5.3. Office Undershelf Lighting Operating Hours..................................................... 51
 

3.5.4. Office Undershelf Lighting System Average Wattages ...................................... 52
 

3.5.5. Office Undershelf Lighting Energy Saving Potential ......................................... 52
 

3.5.6. Technology Benefits in Addition to Energy Savings.......................................... 53
 

3.6. KITCHEN UNDERCABINET LIGHTING........................................................................... 53
 

3.6.1. Introduction....................................................................................................... 53
 

3.6.2. Kitchen Undercabinet Lighting Installed Base ................................................... 54
 

3.6.3. Kitchen Undercabinet Lighting Operating Hours ............................................... 55
 

3.6.4. Kitchen Undercabinet Lighting System Average Wattages ................................ 55
 

3.6.5. Kitchen Undercabinet Lighting Energy Saving Potential ................................... 56
 

3.6.6. Technology Benefits in Addition to Energy Savings.......................................... 56
 

4. OUTDOOR WHITE-LIGHT APPLICATIONS............................................................57
 

4.1. PHOTOPIC VS. SCOTOPIC VISION ................................................................................. 57
 

4.2. STREET AND AREA LIGHTING ..................................................................................... 58
 

4.2.1. Introduction....................................................................................................... 58
 

4.2.2. Street and Area Lighting Installed Base ............................................................. 60
 

4.2.3. Street and Area Lighting Operating Hours......................................................... 61
 

4.2.4. Street and Area Lighting Average Wattages ...................................................... 61
 

4.2.5. Street and Area Lighting Energy Savings Potential............................................ 61
 

4.2.6. Technology Benefits in Addition to Energy Savings.......................................... 62
 

4.3. STEP, PATH, AND PORCH LIGHTING ............................................................................ 62
 

4.3.1. Introduction....................................................................................................... 62
 

4.3.2. Step, Path, and Porch Installed Base .................................................................. 63
 

4.3.3. Step, Path, and Porch Operating Hours .............................................................. 64
 

4.3.4. Step, Path, and Porch Lamp Average Wattages.................................................. 64
 

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4.3.5. Step, Path, and Porch Lighting Energy Saving Potential .................................... 65
 

4.3.6. Technology Benefits in Addition to Energy Savings.......................................... 65
 

5. CONCLUSION................................................................................................................66
 

5.1. BENEFITS AND CAPTURING MARKET SHARE ............................................................... 70
 

6. REFERENCES ................................................................................................................74
 

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TABLES
 

Table 1-1. Summary of Niche Markets Evaluated in this Report ..................................................2
 

Table 1-2: LED Benefits in Addition to Energy Savings ..............................................................5
 

Table 2-1: Critical Inputs for Traffic Signals National Energy Consumption and Savings Potential
 

Estimates ...........................................................................................................................12
 

Table 2-2: Estimated Number of Traffic Signals in the United States, 2007 ...............................13
 

Table 2-3: Traffic Signal Operating Hours by Lamp Type and Color .........................................14
 

Table 2-4: Traffic Signal Wattage for Incandescent and LED Lamps by Color ..........................15
 

Table 2-5: Traffic Signal Percent LED Penetration by Type and Lamp Color ............................16
 

Table 2-6: Traffic Signal Energy Consumption and Savings Estimate, 2007 ..............................16
 

Table 2-7. Critical Inputs for Holiday Lights National Energy Consumption and Savings Potential
 

Estimates ...........................................................................................................................18
 

Table 2-8: Imports of Holiday Lights, 2005-2007 ......................................................................19
 

Table 2-9: Operating Hours for Holiday Lights..........................................................................19
 

Table 2-10: Conventional and LED Holiday Light Lamp Average Wattage ...............................20
 

Table 2-11: Holiday Lights Energy Consumption and Savings Estimate, 2007...........................20
 

Table 2-12. Critical Inputs for Exit Signs National Energy Consumption and Savings Potential
 

Estimates ...........................................................................................................................22
 

Table 2-13: Number of Exit Signs in the United States, 2007.....................................................23
 

Table 2-14: 2007 Exit Sign Percent Market Share by Lamp Type ..............................................23
 

Table 2-15: Exit Sign Wattage by Lamp Type ...........................................................................24
 

Table 2-16: Exit Sign Energy Consumption and Savings Estimate, 2007 ...................................24
 

Table 2-17. Critical Inputs for Electric Signage Energy Consumption and Savings Potential
 

Estimates ...........................................................................................................................26
 

Table 2-18: Electric Signs Annual Sales, Average Price, and Estimated Installed Base, 2007 ....27
 

Table 2-19: Electric Signs Percent Market Share by Lamp Type................................................28
 

Table 2-20: Electric Sign Installed Base, Operating Hours, and Power Consumption.................28
 

Table 2-21: Electric Signs Energy Consumption and Savings Estimate, 2007 ............................29
 

..........................................................................................................................................32
 

Table 3-1: Critical Inputs for Recessed Downlights Energy Consumption and Savings Estimates
 

Table 3-2: Installed Base of Recessed Downlight Fixtures in the U.S., 2007..............................33
 

Table 3-3: Average Operating Hours for Recessed Downlights..................................................33
 

Table 3-4: Average Lamp Wattage for Recessed Downlights.....................................................34
 

Table 3-5: Recessed Downlight Energy Consumption and Savings Estimate, 2007....................34
 

Table 3-6: Critical Inputs for Refrigerated Display Case Lighting Energy Consumption and 

Savings Potential Estimates................................................................................................37
 

Table 3-7: Installed Base of Refrigerated Display Case Lighting Systems in the U.S., 2007.......37
 

Table 3-8: Average System Wattages for Refrigerated Display Case Lighting Systems .............38
 

Table 3-9: Refrigerated Display Case Lighting and Compressor Energy Consumption and 

Savings Estimate, 2007......................................................................................................39
 

Table 3-10: Critical Inputs for Retail Display Lighting Energy Consumption and Savings
 

Potential Estimates.............................................................................................................41
 

Table 3-11: Installed Base of Retail Display Fixtures in the U.S., 2007......................................42
 

Table 3-12: Conventional and LED Retail Display System Wattage ..........................................43
 

Table 3-13: Retail Display Case Energy Consumption and Savings Estimate, 2007 ...................43
 

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Table 3-14: Critical Inputs for Task Lighting Energy Consumption and Savings Potential 

Estimate.............................................................................................................................46
 

Table 3-15: Task Lighting Installed Base and Technology Mix, 2007........................................47
 

Table 3-16: Task Lighting Annual Operating Hours by Lamp Type...........................................48
 

Table 3-17: Commercial Conventional and LED Task Light System Wattages ..........................48
 

Table 3-18: Industrial Conventional and LED Task Light System Wattages ..............................48
 

Table 3-19: Residential Conventional and LED Task Light System Wattages............................49
 

Table 3-20: Task Lights Energy Consumption and Savings Estimate, 2007 ...............................49
 

Table 3-21: Critical Inputs for Office Undershelf Lighting Energy Consumption and Savings
 

Potential Estimate ..............................................................................................................51
 

Table 3-22: Office Undershelf Installed Base, 2007 ...................................................................51
 

Table 3-23: Office Undershelf System Average Wattage and LED Equivalent...........................52
 

Table 3-24: Office Undershelf Energy Consumption and Savings Potential, 2007......................52
 

Table 3-25: Critical Inputs for Kitchen Undercabinet Lighting Energy Consumption and Savings
 

Potential Estimate ..............................................................................................................54
 

Table 3-26: Kitchen Undercabinet Installed Base and Technology Mix, 2007............................55
 

Table 3-27: Kitchen Undercabinet Lighting System Average Wattage and LED Equivalent ......55
 

Table 3-28: Kitchen Undercabinet Energy Consumption and Savings Potential, 2007................56
 

Table 4-1: Critical Inputs for Street and Area Lighting Energy Consumption and Savings
 

Potential Estimates.............................................................................................................60
 

Table 4-4: Energy Consumption and Savings Potential of LED Street and Area Lighting, 2007.61
 

Table 4-5: Critical Inputs for Step, Path and Porch Light Energy Consumption and Savings
 

Table 4-2: Street and Area Light Installed Base, 2007................................................................60
 

Table 4-3: Lamp Wattage of Street and Area lights....................................................................61
 

Potential Estimates.............................................................................................................63
 

Table 4-6: National Installed Base and Technology Mix of Step, Path and Porch Lights, 2007 ..64
 

Table 4-7: Average Lamp Wattage for Step, Path, and Porch Lights ..........................................64
 

Table 4-8: Step, Path and Porch Lighting Energy Consumption and Savings Estimate, 2007 .....65
 

Table 5-1. Energy Consumption and Savings in 2007 of Applications Evaluated.......................69
 

Table 5-2. Potential and Cumulative Energy Savings of Applications Evaluated........................70
 

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FIGURES
 

Figure 1-1: National Energy Consumption and Savings Methodology ........................................ 3
 

Figure 4-1: Photopic and Scotopic V-λ Curves ......................................................................... 58
 

Figure 5-1: Site Electricity Savings in 2007 Attributable to LED Market Penetration................ 67
 

Figure 5-2: Maximum Site Electricity Savings With 100% LED Market Penetration ................ 68
 

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List of Acronyms and Abbreviations 

ANSI American National Standards Institute 

ASM Annual Survey of Manufacturers 

CALiPER Commercially Available LED Product Evaluation and Reporting Program 

CASE Codes and Standards Enhancement 

CBECS Commercial Buildings Energy Consumption Survey 

CEE Consortium for Energy Efficiency 

CFL Compact Fluorescent Lamp 

CRI Color Rendering Index 

DOE U.S. Department of Energy 

DOL U.S. Department of Labor 

DSM Demand Side Management 

EIA Energy Information Administration 

EISA Energy Independence and Security Act of 2007 

EPA Environmental Protection Agency 

EPACT Energy Policy Act of 2005 

FHWA Federal Highway Administration 

HID High Intensity Discharge lamp 

IESNA Illuminating Engineering Society of North America 

ITE Institute of Transportation Engineers 

LBL Lawrence Berkeley National Laboratory 

LED Light Emitting Diode 

LRC Lighting Research Center 

MECS Manufacturing Energy Consumption Survey 

MW Megawatt 

NCI Navigant Consulting Incorporated 

NEMA National Electrical Manufacturers Association 

PG&E Pacific Gas and Electric 

PNL Pacific Northwest National Laboratory 

RECS Residential Energy Consumption Survey 

RPI Rensselaer Polytechnic Institute 

SMUD Sacramento Municipal Utility District 

SSL Solid State Lighting 

STMG Signs of the Times Magazine 

TWh Terawatt-hour 

UIE University of Illinois Extension 

USITC United States International Trade Commission 

W Watt 

WSU Washington State University 

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Executive Summary 

Light Emitting Diodes (LEDs), a type of Solid State Lighting (SSL), offer the electric lighting 

market a new and revolutionary light source that saves energy and improves quality, 

performance, and service. Today, LEDs are competing successfully with conventional, 

incandescent light sources that use color filters to generate the desired colored light emission, 

such as those found in traffic signals and exit signs. In these and other applications, consumers 

choose LEDs because they offer more cost-effective performance than incandescent lamps. 

This report presents research findings for twelve different niche markets where LEDs are 

competing or are poised to compete with traditional light sources, such as incandescent, halogen, 

fluorescent, neon, and high-intensity discharge (HID). LEDs are challenging traditional light 

sources, because the LED offers lower operating costs and better reliability and performance. 

This report presents estimates of the energy saved due to estimated current levels of LED market 

penetration. This report also estimates the “overnight” technical potential energy savings if these 

markets switched completely to LEDs. The markets analyzed in this report are classified into 

three groups: 

Colored-Light Applications 

• Traffic Signals and Pedestrian Crossings 

• Decorative Holiday Lights 

• Exit Signs 

• Electric Signage 

Indoor White-Light Applications 

• Recessed Downlights 

• Refrigerated Display Cases 

• Retail Display 

• Task Lights 

• Office Undershelf Lights 

• Kitchen Undercabinet Lights 

Outdoor White-Light Applications 

• Street and Area Lights 

• Step, Path, and Porch Lights 

This study found that the applications where LEDs have the highest level of market penetration 

are colored-light applications such as traffic signals, exit signs, holiday lights and electric 

signage. In these installations, LEDs have the advantage of only producing light in the color of 

interest to the end-user, thus they can do so more efficiently and reliably than filtered fullspectrum sources. The applications where market adoption is maturing or poised to grow include 

traffic signals and pedestrian crossings, decorative holiday lights, exit signs, electric signage, and 

refrigerated display case lighting. The applications where market adoption has yet to occur, but 

for which high quality LED products are currently available include recessed downlights, retail 

display, task lights, office undershelf and kitchen undercabinet lights, street and area lights, and 

outdoor step, path, and porch lights. In these and a growing list of other applications, wellxi 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

designed LED products can save energy, and provide equivalent or better lighting quality, 

compared to conventional lighting technologies. In addition, the potential for very long service 

life of LED products, and greatly reduced lighting maintenance costs, is an important factor in 

light source selection for many applications. These and other ancillary benefits of using LEDs 

are discussed in Table 1-2. 

This report presents the findings of analysis on these twelve LED niche applications, addressing 

four fundamental questions: 

 How much energy is consumed by lighting technologies in these applications? 

 What is the estimated market penetration of LED technology today? 

 What are the energy savings resulting from the current level of LED market penetration? 

 What would the energy savings be from 100% LED market penetration? 

For colored-light, indoor and outdoor white-lighting applications, energy savings are reported in 

both trillion watt-hours (TWh) of national electricity savings as well as trillion British thermal 

units (TBtu) of primary energy consumption saved at the power plant level from the avoided 

electricity, assuming the average national generation fuel mix in the U.S.1 To put these figures 

into perspective, energy savings are also presented in terms of the output of an equivalent 

number of large (1000 MW) coal power plants and the annual electricity consumption of 

thousands or millions of typical U.S. households. 

Figure ES.1 summarizes the electricity savings (at the site) from the top two colored-light, indoor 

white-light, and outdoor white-light niche applications with the greatest electricity savings in 

2007 or if no savings have yet occurred in that type of application, the greatest electricity savings 

potential. Also displayed is the corresponding number of coal power plants that could be 

avoided due to these potential electricity savings. 

1 Primary energy savings are calculated by multiplying electricity savings by the 2007 source-to-site conversion 

factor (EIA 2008). Power plant and household numbers are estimated by dividing electricity savings by the annual 

output of a 1000 MW coal power plant with an average capacity factor of 72.6% (EIA 2007b) and by the average 

residential household electricity consumption (DOE 2007a), respectively. 

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81.2 | 12.8

12.6 | 2.0

44.7 | 7.0

4.85 | 0.76 5.18 | 0.82 2.1 | 0.33

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

Traffic Signals ExitSigns Refrigerated

Display Cases

Recessed

Downlights

Step,Path,and

Porch lights

StreetandArea

Lights

Colored Light IndoorWhite-Light OutdoorWhite-Light

Electricity

S

avin

g

s

(TWh

/y

r)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

C

oal Power

Pla

n

ts

A

void

ed (1

000

MW

s

ta

tio

n

s)

Electricity Savings Potential

Electricity Savings, 2007

Figure ES.1 Electricity Saved and Potential Savings of Selected Niche Applications 

In 2007, the current penetration of LEDs in the twelve niche applications analyzed in this report 

resulted in a realized electricity savings of 8.7 TWh per year. To put this figure in perspective, 

the Department of Energy estimates that the total annual energy consumption for all lighting 

technologies in the U.S. was 765 TWh in 2001 (DOE, 2002a). 

Table ES.1 provides a detailed summary including both electricity consumption and primary 

energy consumption. Some sectors have estimates of zero percent LED penetration, thus 

contribute no savings to the total of 8.7 TWh. In general, the average luminaire efficacy of the 

LED for all twelve applications was assumed to be between 22.5 lm/W and 60.9 lm/W. More 

detailed information on this and other assumptions for all of the applications can be found in the 

body of the report. 

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Table ES.1 Energy Consumption and Savings in 2007 of Applications Evaluated 

Application 

Annual Electricity 

Consumption 

(TWh) 

LED Market 

Penetration 

Electricity 

Savings 2007 

(TWh) 

Primary Energy 

Savings 2007 

(TBtu) 

Colored Light Applications 

Traffic Signals 2.38 52% 2.82 30.4 

Decorative Holiday Lights 6.63 5.2% 0.33 3.53 

Exit Signs 2.50 88% 4.56 49.2 

Electric Signage 11.6 6.1% 0.95 10.3 

Indoor White-Light Applications 

Recessed Downlights 103.1 0.0% 0.0 0.0 

Refrigerated Display Cases 13.4 3.6% 0.08 0.81 

Retail Display 32.0 0.0% 0.0 0.0 

Task Lighting 18.8 0.0% 0.0 0.0 

Kitchen Under-Cabinet Lighting 2.84 0.0% 0.0 0.0 

Office Undershelf Lighting 3.43 0.0% 0.0 0.0 

Outdoor White-Light Applications 

Street and Area Lights 178.3 0.0% 0.0 0.0 

Step, Path, and Porch lights 22.0 0.0% 0.0 0.0 

Total 397 TWh -- 8.7 TWh 94 TBtu 

As shown in Table ES.1, the electricity savings in 2007 attributable to LEDs are dominated by 

exit signs, where they have achieved an estimated 88% market penetration. This niche market 

represents 52% of the total energy savings attributable to LEDs in 2007. The second most 

significant energy saving niche market in 2007 was traffic signal heads. In this application, 

approximately 52% of the signals are estimated to incorporate LED technology, representing 

approximately 32% of the total energy savings from LEDs in 2007. From negligible penetration 

in 2002, LEDs have reached 6.1% of the electric signage market and 5.2% of the decorative 

holiday lights market, contributing to 11% and 4% of the total energy savings from LEDs in 

2007, respectively. LEDs have also begun to penetrate the refrigerated display case market, 

reaching 3.6% penetration in 2007. Other applications such as recessed downlights, retail 

display, task lighting, street and area lights, and step, path, and porch lights were estimated to 

have insignificant market penetration of LEDs. Commercial LED products are available in these 

markets; however significant market adoption has yet to occur. 

Table ES.2 presents the potential energy savings in each market from converting the remainder 

of the sockets to LED technology. It also presents the theoretical maximum energy savings (i.e., 

the sum of 2007 electricity [or primary energy] savings and potential electricity [or primary 

energy] savings) attributable to LEDs for each market for a complete conversion to LED relative 

to the conventional lighting technology. For applications with no market penetration of LEDs 

and no energy savings in 2007, energy savings potential equals theoretical maximum energy 

savings. 

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Table ES.2 Potential and Theoretical Maximum Energy Savings of Applications Evaluated 

Application 

Electricity 

Savings 

Potential (TWh) 

Primary Energy 

Savings 

Potential (TBtu) 

Theoretical 

Maximum 

Electricity 

Savings (TWh) 

Theoretical 

Maximum 

Primary Energy 

Savings (TBtu) 

Colored Light Applications 

Traffic Signals 2.03 21.9 4.85 52.3 

Decorative Holiday Lights 5.97 64.4 6.30 67.9 

Exit Signs 0.63 6.78 5.18 55.9 

Electric Signage 6.58 71.0 7.53 81.3 

Indoor White-Light Applications 

Recessed Downlights 81.2 876.6 81.2 876.6 

Refrigerated Display Cases 2.0 21.6 2.1 22.4 

Retail Display 7.87 84.9 7.87 84.9 

Task Lighting 13.0 140.1 13.0 140.1 

Kitchen Under-Cabinet Lighting 2.22 24.0 2.22 24.0 

Office Undershelf Lighting 1.37 14.8 1.37 14.8 

Outdoor White-Light Applications 

Street and Area Lights 44.7 482.0 44.7 482.0 

Step, Path, and Porch lights 12.6 136.3 12.6 136.3 

Total 180 TWh 1944 TBtu 189 TWh 2039 TBtu 

Of the applications analyzed in this report, recessed downlights, street and area lights, 

refrigerated display cases, task lights and outdoor step, path, and porch lighting represent the top 

five applications with the greatest future savings potential for LEDs. Of these, recessed 

downlights appear to be the most promising, with 81.2 TWh of potential savings. 

The potential for greater energy efficiency with LED sources is an important consideration, 

along with other attributes that might induce lighting users to adopt this technology over 

conventional light sources. In several applications, well-designed LED products and luminaires 

can offer the following benefits, relative to conventional lighting products: 

•	 Reduced Energy Consumption – LED devices can offer a more energy efficient means of 

producing light, particularly when compared to incandescent sources. In an application such 

as a traffic signal, an 8W LED red signal head replaces a 135W reflector lamp – a 94% 

reduction in energy consumption - while complying with the same safety standards. And as 

SSL technology evolves, the efficiency of these devices will continue to improve, enabling 

even greater energy savings through conversion to LED. 

•	 Long Operating Life – Commercial and industrial specifiers are generally interested in using 

a light source that is reliable and lasts a long time. Frequent lamp replacements can be costly 

from a maintenance perspective, and failed lamps could expose lamp operators to liabilities 

(e.g., traffic signals or exit signs). In fact, maintenance savings are one of the primary reasons 

behind market adoption of LEDs in several markets, such as electric signage, street and area 

lights, and retail display lighting. Presently, LED technology offers operating lives that are 

xv 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

approximately twenty-five times longer than those of incandescent sources.2 Researchers 

indicate that operating life will continue to improve as the technology develops. 

•	 Lower Maintenance and Life-Cycle Costs - The longer life of LEDs translates into less 

frequent relamping and lower maintenance costs. Although several LED products cost more 

than conventional products, the lower energy consumption and extended operating life (and 

associated maintenance savings) equate to lower life-cycle costs. For example, the cost of 

ownership, including energy and maintenance costs, of one intersection of LED traffic 

signals is about ninety percent less than that of an intersection of incandescent traffic signals 

(ENERGY STAR, 2006, 2008a). 

•	 Reduced Radiated Heat – LEDs convert a higher proportion of electricity into visible light 

than incandescent sources. LED conversion efficiency has improved rapidly and is expected 

to continue; current LED luminaires can be equivalent to or more efficient than fluorescent 

and HID luminaires at converting power to visible light. Further, incandescent sources 

convert most of the power they use into infrared (IR) radiation (radiated heat), and some 

discharge sources emit both IR and ultraviolet (UV), but LEDs emit neither (unless 

specifically designed to do so). Instead, the waste heat generated by the LED must be 

removed by heat-conducting material (a “heat sink”). The reduction in heat radiated into 

conditioned space may reduce the air-conditioning or refrigeration load for some 

applications. 

•	 Minimal Light Loss – Unlike conventional lamps, LED luminaires do not need color filters 

to produce colored-light. In colored-light applications, light loss can be minimized by 

matching the color of the LED chip emitter to the color of the translucent covering on the 

lighting fixture. Furthermore, light emitted from an LED device is more directional and 

controlled, meaning that fewer photons are trapped within the lighting fixture. By contrast, 

conventional lamps have a 360 degree emission range, which results in lower fixture 

efficiencies as light is lost as the light is dispersed to the back of the fixture. 

•	 Dimmability and Controllability – For most applications, LED luminaires can be designed 

with dimming controls and motion sensors to adjust brightness levels. For example, LEDs 

can be dimmed more efficiently than fluorescents because rapid and frequent on/off cycles 

do not affect the life of the LED, enabling the use of movement-triggered controls. These 

controls can reduce the annual operating hours of the LED system and lead to greater energy 

savings than we calculate in this report. 

•	 Directional Illumination – The LED sources can be targeted to illuminate particular parts of 

the packaging or prices in the display case, calling customer’s attention to aspects of the 

display case that may result in a sale. Similarly, LED task, office undershelf, or kitchen 

undercabinet lights can be targeted to illuminate particular parts of the work space, leading to 

higher fixture efficiencies and higher illumination to complete tasks, with less light scattered 

away from the work space. 

2 We assume that manufacturers’ claims of 50,000-hour LED lifetimes can be substantiated. However, these claims 

have not been independently verified by DOE. 

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•	 Durability – the light production mechanism for LED devices is fundamentally different from 

traditional light sources such as incandescent and fluorescent. LED sources produce light by 

passing a current through thin layers of a semi-conductive material, which causes the 

recombination of electron-hole pairs in the material which emit light. Inherent in this solidstate light production mechanism is the ability of the source to resist vibration and impact, 

making it an ideal light source for refrigerated display cases, office undershelf and kitchen 

undercabinet lighting. The LED is encased in a tough epoxy plastic resin instead of a fragile 

glass bulb, thus, they are more resistant to shattering or impact damage in these applications. 

•	 Safety Improvements – For several applications, characteristics specific to LEDs lead to 

safety enhancements. LED luminaires are made of multiple diodes, and are less likely to fail 

simultaneously, leading to less down time for traffic signals, enhancing traffic flow and 

safety. In addition, LED holiday lights emit less heat than incandescents, and can reduce the 

current total of 210 home-structure fires per year due to ignited Christmas trees (Ahrens, 

2007). LED electric signage is also typically operated at lower voltages and direct current 

which are safer for maintenance workers to handle than neon, which operates at 12,000 to 

15,000 volts of alternating current. 

•	 Color Maintenance - Monochromatic LEDs for colored light applications allow the 

elimination of filters and hence better color control and color life than conventional 

technologies. 

•	 Smaller Package Size – Due to their compact size, LED devices are an excellent option 

where size or weight is a concern. For example, LED lighting provides more shelf space for 

merchandise in a refrigerated display case. This is because the LED and driver system is 

much smaller than a fluorescent lamp and ballast system, and can be distributed throughout 

the display case, unlike fluorescents. 

•	 Uniform Illumination. – LED devices offer distinct advantages where light encroachment or 

glare is a problem. For example, through the use of lenses and lighting controls, LED street 

and area lights, and step, path, and porch light luminaires can better distribute the light across 

the ground, allowing more uniform illumination. 

•	 Battery Back-Up Capability - Traffic signals that include red, green, and yellow LEDs 

consume around one-tenth as much power and LED exit signs consume about one-fifth as 

much power as with incandescent sources. For this reason, battery back-up power supplies 

are available which can operate during power failures to ensure smooth flow of vehicular 

traffic or continuous delineation of building routes of egress. Many agencies use yellow LED 

signals for battery back-up reasons in emergency situations. For instance, if yellow LED 

signals were used in flashing mode, work crews would have a few extra hours to handle 

emergency situations (Bullough, 2003b). 

•	 Adjustable Color – Storeowners could also easily alter the intensity and color of the LED 

light to augment particular colors in the products. Recent marketing studies have shown that 

these features offer enhanced appeal to the human eye compared to other lighting systems. 

xvii 
 

 

 

 

 

 

 

 

 

Study subjects strongly preferred display cases with LED lighting systems at half the 

illumination levels of fluorescent systems (Narendran, 2003b). 

•	 Light Pollution Reduction – The directional quality of LED street and area or step, path, and 

porch luminaires leads to more lumens to light the road plane or path and fewer lumens 

scattered upward, reducing light pollution. 

These and other qualities of LED sources are encouraging the marketplace to adopt LED 

technology in niche applications today, and general illumination applications in the future. As 

the market for LED technologies expands, industry will continue to develop manufacturing 

processes that reduce the cost of LED lamps, which will accelerate market adoption. 

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1. Introduction 

Solid-state lighting (SSL) has the potential to revolutionize the lighting market through the 

introduction of more energy efficient light sources. LEDs can be found in a range of niche 

market applications involving colored light emission, such as exit signs, traffic signals, and 

electric signage. Technical advances have made light emitting diodes (LEDs) competitive in not 

only in these colored-light applications, but recently in some outdoor white-light and indoor 

white-light applications as well, such as recessed downlights, refrigerated display cases, street 

and area lights and outdoor step, path, and porch lights. LED technology is capturing market 

share in these new applications because well-designed LED products exist that can provide 

energy savings, equivalent or better lighting quality, and cost-effective lighting service, 

depending on usage, electricity rates, and maintenance costs compared to conventional light 

sources such as incandescent, neon, high-intensity discharge (HID), and fluorescent. In addition 

to energy savings, LEDs can offer longer operating lifetimes (>50,000 hours), lower operating 

costs, improved durability, and improved color rendition. As LED technology advances – 

reducing costs and improving efficiency–LEDs will build market share in these and other niche 

markets. 

1.1. LED Technology Background 

The first LEDs were produced in the 1950s by British scientists who discovered that the 

semiconductor Gallium Arsenide (GaAs) emitted a low-level of infrared light when passed with 

a current. This first LED had properties that resembled the transistor – high tolerance for shock 

and vibration and long operating life. While the efficacy3 of the first LEDs was extremely low 

(approximately 1 lumen per watt), researchers have improved this technology over the past four 

decades. Today, white LED devices are capable of operating at 134 lumens per watt in the 

laboratory (Stevenson, 2007). Present day white LED commercial devices have reached 

efficacies of 101 lm/W, comparable to the efficacies of certain fluorescent and high-intensity 

discharge (HID) lamps, with efficacies still rising rapidly (Audin et al., 1997, 2.2.5; Nichia).

4 

Compared to incandescent, neon, fluorescent or high-intensity discharge lamps, LEDs produce 

light using a fundamentally different principle. Whereas the traditional light sources produce 

light by heating a filament to incandescence or establishing an electrical arc through a gas 

mixture, LEDs emit light from a small semiconducting chip when a current is applied to it. 

LEDs are semiconductors created by bringing together similar materials with slightly different 

electronic properties to create a “PN junction”. In a PN junction, the “P” material contains an 

excess of positive charges (also called holes) due to the absence of electrons. The “N” material 

contains an excess of negative charges due to the presence of electrons. When a voltage is 

applied to this PN junction, the electrons and the holes combine, releasing energy that can take 

the form of visible light. 

Unlike the incandescent lamp, LEDs can emit light in a narrow wavelength band, making the 

emission appear colored. Since the initial breakthrough in the 1950s, research has focused on 

3 Efficacy is the efficiency metric for light sources, measured in lumens of light output per watt of input power. 4 Efficacies of incandescent, fluorescent, and HID lamps from Audin, L., Houghton, D., et al. Lighting Technology 

Atlas. E Source, Inc., Boulder, CO (1997). (p 2.2.5) Efficacy of LED: Nichia NS6W083B SMD Power LED. 

1 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

- -

 

 

 

 

 

developing new LED semiconductor materials that enable LEDs to emit each color in the visible 

spectrum. Research has also improved the efficacy and power handling capability of LED 

devices themselves, enabling them to now compete with conventional technologies in coloredlighting applications. Many of these applications where LEDs compete or are poised to compete 

are discussed in this report. 

Today, the majority of white-light LEDs emit blue or ultraviolet light onto a phosphor. The 

phosphor then converts the blue or ultraviolet light emitted by the LED into white light. 

Assembling three or more LED chips that emit in the blue, green and red spectral zones can also 

create white-light LED packages. In this type of multi-chip design, the individual light emission 

from each of the chips will blend to create a white-light emission from the package. This 

approach, currently more expensive than the phosphor method, has the potential to reach higher 

efficacies (DOE, 2008). White light can also be created with just two LEDs, (e.g. yellow and 

blue), when good color rendering is not critical. When color rendering is critical, warm-white 

light, similar to the output of an incandescent lamp, can be created by using specific phosphors 

designed to emit light in the warmer spectral range. Alternatively, light from cool white LEDs 

and a monochromatic orange-red LED can be blended to produce a warm-white light. 

1.2. Niche Markets Reviewed 

The Department identified twelve LED niche market applications for this study. Shown in Table 

1-1, these niche markets are grouped into three general categories: colored-light applications, 

indoor white-light applications, and outdoor white-light applications. The baseline energy 

consumption of some of these niche markets may be very small; however they were studied to 

understand some of the benefits of LED technology that are encouraging various markets to 

convert. 

Table 1-1. Summary of Niche Markets Evaluated in this Report 

Niche Market Colored Light White Light 

Colored-Light Applications 

Traffic Signals and Pedestrian Crossings X 

Decorative Holiday Lights X X 

Exit Signs X 

Electric Signage X X 

Indoor White-Light Applications 

Recessed Downlights X 

Refrigerated Display Case Lighting X 

Retail Display X X 

Task Lighting X 

Office Under-cabinet Lighting X 

Kitchen Under-cabinet Lighting X 

Outdoor White-Light Applications 

Street and Area Lighting X 

Step, Path, and Porch Lighting X 

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The Department recognizes that the twelve niche markets evaluated in this report do not 

represent an exhaustive list of all the applications and installations where LED devices can be 

found today. In addition to these, other popular niche market applications for LED devices 

include: indicator lights on electronic goods, novelty sneaker flashing lights, bicycle safety 

lights, camping head-lamps, flashlights, machine vision, museum or art gallery display lighting, 

architectural accent lighting, automotive lights, and mobile device, computer monitor and 

television display screen illumination. 

1.3. Estimated National Energy Consumption Methodology 

This study evaluates the 2007 and “overnight” energy savings potential of LEDs in niche and 

emerging applications. Twelve applications are reviewed, consisting of four colored-light, five 

indoor white-light, and two outdoor white-light niche applications. Energy savings are presented 

both in terms of onsite electricity savings in trillion watt-hours (TWh) and primary energy 

savings at the power station level (in trillion British thermal units (TBtu), assuming the average 

national generation fuel mix in the U.S.5 A general methodology was applied across the twelve 

niche applications to estimate the national energy consumption of each application. 

Number of 

Lamps 

Installed 

Energy Consumption and 

Savings Estimate 

Annual 

Operating 

Hours 

Wattage 

per 

Lamp 

Primary Energy Savings 

(power plant) 

% LED 

Penetration in 

2007 

X X X 

Figure 1-1: National Energy Consumption and Savings Methodology 

Figure 1-1 illustrates the four critical pieces used to prepare an estimate of the energy 

consumption and the energy savings potential of each niche application. These include: the 

number of lamps installed, the annual operating hours, the wattage per lamp and the percent of 

LED market penetration. The four critical pieces were estimated by reviewing literature and 

market studies, examining available databases, and conducting interviews with researchers and 

industry experts. The specific sources and any variances on this methodology are described at the 

start of each niche application section. 

5 Primary energy savings are calculated by multiplying electricity savings by the 2007 source-to-site conversion 

factor (EIA 2008). Power plant and household numbers are estimated by dividing electricity savings by the annual 

output of a 1000 MW coal power plant with an average capacity factor of 72.6% (EIA 2007a) and by the average 

residential household electricity consumption (DOE 2007a), respectively. 

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The energy consumption and savings estimate results are highly sensitive to the state of LED 

technology. The methodology only considers currently available LED technology. For those 

applications where LEDs have not yet significantly penetrated the market, LED efficacies are 

equal to the best-in-class LED luminaires available. In the future, advances in LED technology 

will significantly increase potential energy savings compared to the calculations conducted in 

this report. LED device and luminaire efficacies are improving rapidly, and an ever increasing 

diversity of applications are becoming available. Since 2002, commercial white LED device 

efficacies have increased from 30 lumens/watt (DOE, 2006a) to about 100 lumens/W in 2008.

6 

White LED luminaire efficacies are projected to advance from 47 lumens/watt in 2007 to 97 

lumens/watt in 2010, and reaching 161 lumens/watt in 2015 (DOE, 2008a). 

The energy consumption and savings of the twelve niche applications analyzed in this report are 

also highly dependent on the baseline conventional lamps used. Our estimates are based on data 

for conventional lamp efficacies and market penetration in 2007. However, the total energy 

consumed by conventional lamps may fall, as might LED energy savings, due to future energy 

conservation standards,7 energy legislation, or technical advancement in the conventional light 

sources. For example, on December 19, 2007, the Energy Independence and Security Act of 

2007 (EISA 2007) went into effect, which included provisions to set higher efficacy 

requirements for all general service incandescent lamps manufactured after 2014, and an efficacy 

requirement up to 45 lm/W in 2020, effectively banning the traditional incandescent lamp.8 

EISA 2007 will lower the annual energy consumption of the baseline conventional lighting 

technologies for the twelve applications analyzed in this report, thereby lowering the energy 

savings potential of LEDs in the future, compared to the calculations conducted in this report. 

Energy consumption and potential savings from LEDs also depend on the underlying market 

dynamics of the twelve niche applications analyzed in this report. Some applications may grow 

in popularity in the future, such as recessed downlights, a light fixture that is more prevalent in 

new construction compared to older buildings. Other applications may decline due to decreasing 

market demand for the product, such as decorative holiday lights which have decreased from 371 

million to 295 million miniature light strings during the past five years. These market-specific 

changes may increase or decrease the potential energy consumption and savings of LEDs 

according to the overall size of the niche application. 

The magnitude of each of these effects – LED advancements, baseline efficacies, and market 

dynamics – is uncertain and so is the overall impact on energy consumption and savings. Thus, 

6 A CREE warm white LED reached 99 lm/W (Compound Semiconductor) and Nichia (NS6W083B) reached 101 

lm/W in 2008. 7 Energy conservation standards will be applicable for fluorescent and incandescent reflector lamps by 2012, and for 

fluorescent ballasts by 2014. A determination on whether standards are economically justified for HID lamps is 

currently underway. For more information, visit http://www.eere.energy.gov/buildings/appliance_standards/ 

8 Section 321(a)(3) of EISA 2007 (P.L. 110-140) establishes energy conservation standards for general service 

incandescent lamps for rated lumen ranges, maximum rated wattage, and minimum rate lifetime, effective January 1, 

2014 for general service and modified spectrum incandescent lamps. In effect, these standards establish minimum 

wattage requirements for general service lamps. For example, a lamp with the equivalent lumen output of a 

traditional 100W lamp must only consume 72 W, a lamp with the equivalent lumen output of a traditional 75W 

lamps must only consume 53 W, and a lamp with the equivalent lumen output of a traditional 60W lamp must only 

consume 43W. 

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the estimates for energy consumption and savings potential from LEDs presented in this report 

represent a brief snapshot of the state of the twelve analyzed lighting applications in 2007. 

1.4. Technology Benefits in Addition to Energy Savings 

There are several benefits outside of energy savings that are driving the adoption of LED 

technology in the twelve applications analyzed in this report. In addition to yielding more than 

94 TBtu per year of primary energy savings, and potentially a further 2039 TBtu per year when 

the market reaches saturation, LED products offer other advantages over conventional products. 

These advantages as well as the niche market where these advantages are applicable are listed in 

Table 1-2. 

Table 1-2: LED Benefits in Addition to Energy Savings 

Benefit Applicable Niche Markets 

Long Operating Life – Commercial and industrial specifiers are 

generally interested in using a light source that is reliable and 

lasts a long time. Frequent lamp replacements can be costly 

from a maintenance perspective, and failed lamps could expose 

lamp operators to liabilities (e.g., traffic signals or exit signs). In 

fact, maintenance savings are one of the primary reasons behind 

market adoption of LEDs in several markets, such as electric 

signage, street and area lights, and retail display lighting. 

Presently, LED technology offers operating lives that are 

approximately twenty-five times longer than those of 

incandescent sources.9 Researchers indicate that operating life 

will continue to improve as the technology develops. 

Traffic Signals and 

Pedestrian Crossings; 

Decorative Holiday Lights; 

Exit Signs; 

Electric Signs; 

Recessed Downlights; 

Refrigerated Display Cases; 

Retail Display; 

Task Lights; 

Office Undershelf; 

Kitchen Undercabinet; 

Street and Area Lights; 

Step, Path and Porch Lights 

Lower Maintenance and Life-Cycle Costs - The longer life of 

LEDs translates into less frequent relamping and lower 

maintenance costs. Although several LED products cost more 

than conventional products, the lower energy consumption and 

extended operating life (and associated maintenance savings) 

equate to lower life-cycle costs. For example, the cost of 

ownership, including energy and maintenance costs, of one 

intersection of LED traffic signals is about ninety percent less 

than that of an intersection of incandescent traffic signals 

(ENERGY STAR, 2006, 2008a). 

Traffic Signals and 

Pedestrian Crossings; 

Decorative Holiday Lights; 

Exit Signs; 

Electric Signs; 

Recessed Downlights; 

Refrigerated Display Cases; 

Retail Display; 

Task Lights; 

Office Undershelf; 

Kitchen Undercabinet; 

Street and Area Lights; 

Step, Path and Porch Lights 

9 We assume that manufacturers’ claims of 50,000-hour LED lifetimes can be substantiated. However, these claims 

have not been independently verified by DOE. 

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Table 1-2: LED Benefits in Addition to Energy Savings (continued) 

Benefit Applicable Niche Markets 

Reduced Radiated Heat – LEDs convert a higher proportion of Traffic Signals and 

electricity into visible light than incandescent sources. LED Pedestrian Crossings; 

conversion efficiency has improved rapidly and is expected to Decorative Holiday Lights; 

continue; current LED devices are equivalent or more efficient Exit Signs; 

than fluorescent and HID sources at converting power to visible Electric Signs; 

light. Further, incandescent sources convert most of the power Recessed Downlights; 

they use into infrared (IR) radiation (radiated heat), and some Refrigerated Display Cases; 

discharge sources emit both IR and ultraviolet (UV), but LEDs Retail Display; 

emit neither (unless specifically designed to do so). Instead, the Task Lights; 

waste heat generated by the LED must be removed by heat- Office Undershelf; 

conducting material (a “heat sink”). The reduction in heat Kitchen Undercabinet; 

radiated into conditioned space may reduce the air-conditioning Street and Area Lights; 

or refrigeration load for some applications. Step, Path and Porch Lights 

Minimal Light Loss – Unlike conventional lamps, LED 

luminaires do not need color filters to produce colored-light. In 

colored-light applications, light loss can be minimized by 

matching the color of the LED chip emitter to the color of the 

translucent covering on the lighting fixture. Furthermore, light 

emitted from an LED device is more directional and controlled, 

meaning that fewer photons are trapped within the lighting 

fixture. By contrast, conventional lamps have a 360 degree 

emission range, which results in lower fixture efficiencies as light 

is lost as the light is dispersed to the back of the fixture. 

Traffic Signals and 

Pedestrian Crossings; 

Decorative Holiday Lights; 

Exit Signs; 

Electric Signs; 

Recessed Downlights; 

Refrigerated Display Cases; 

Retail Display; 

Task Lights; 

Office Undershelf; 

Kitchen Undercabinet; 

Street and Area Lights; 

Step, Path and Porch Lights 

Dimmability and Controllability – For most applications, LED 

luminaires can be designed with dimming controls and motion 

sensors to adjust brightness levels. For example, LEDs can be 

dimmed more efficiently than fluorescents because rapid and 

frequent on/off cycles do not affect the life of the LED, enabling 

the use of movement-triggered controls. These controls can 

reduce the annual operating hours of the LED system and lead to 

greater energy savings than we calculate in this report. 

Decorative Holiday Lights; 

Electric Signs; 

Recessed Downlights; 

Refrigerated Display Cases; 

Retail Display; 

Task Lights; 

Office Undershelf; 

Kitchen Undercabinet; 

Street and Area Lights; 

Step, Path and Porch Lights 

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Table 1-2: LED Benefits in Addition to Energy Savings (continued) 

Benefit Applicable Niche Markets 

Directional Illumination – The LED sources can be targeted to 

illuminate particular parts of the packaging or prices in the 

display case, calling customer’s attention to aspects of the 

display case that may result in a sale. Similarly, LED task, 

office undershelf, or kitchen undercabinet lights can be targeted 

to illuminate particular parts of the work space, leading to higher 

fixture efficiencies and higher illumination to complete tasks, 

with less light scattered away from the work space. 

Recessed Downlights; 

Refrigerated Display Cases; 

Retail Display; 

Task Lights; 

Office Undershelf; 

Kitchen Undercabinet; 

Street and Area Lights; 

Step, Path and Porch Lights 

Durability – the light production mechanism for LED devices is 

fundamentally different from traditional light sources such as 

incandescent and fluorescent. LED sources produce light by 

passing a current through thin layers of a semi-conductive 

material, which causes the recombination of electron-hole pairs 

in the material to emit light. Inherent in this solid-state light 

production mechanism is the ability of the source to resist 

vibration and impact, making it an ideal light source for 

refrigerated display cases, office undershelf and kitchen 

undercabinet lighting. The LED is encased in a tough epoxy 

plastic resin instead of a fragile glass bulb, thus, they are more 

resistant to shattering or impact damage in these applications. 

Traffic Signals and 

Pedestrian Crossings; 

Decorative Holiday Lights; 

Exit Signs; 

Electric Signs; 

Refrigerated Display Cases; 

Task Lights; 

Step, Path and Porch Lights 

Safety Improvements – For several applications, characteristics 

specific to LEDs leads to safety enhancements. LED luminaires 

are made of multiple diodes, and are less likely to fail 

simultaneously, leading to less down time for traffic signals, 

enhancing traffic flow and safety. In addition, LED holiday 

lights emit less heat than incandescents, and can reduce the 

current total of 210 home-structure fires per year due to ignited 

Christmas trees (Ahrens, 2007). LED electric signage is also 

typically operated at lower voltages and direct current which are 

safer for maintenance workers to handle than neon, which 

operates at 12,000 to 15,000 volts of alternating current. 

Traffic Signals and 

Pedestrian Crossings; 

Decorative Holiday Lights; 

Exit Signs; 

Electric Signs; 

Street and Area Lights 

Color Maintenance - Monochromatic LEDs for colored light 

applications allow the elimination of filters and hence better 

color control and color life than conventional technologies. 

Traffic Signals and 

Pedestrian Crossings; 

Decorative Holiday Lights; 

Exit Signs; 

Electric Signs 

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Table 1-2: LED Benefits in Addition to Energy Savings (continued) 

Benefit Applicable Niche Markets 

Smaller Package Size – Due to their compact size, LED devices 

are an excellent option where size or weight is a concern. For 

example, LED lighting provides more shelf space for 

merchandise in a refrigerated display case. This is because the 

LED and driver system is much smaller than a fluorescent lamp 

Refrigerated Display Cases; 

Retail Display; 

Task Lights 

and ballast system, and can be distributed throughout the display 

case, unlike fluorescents. 

Uniform Illumination. – LED devices offer distinct advantages 

where light encroachment or glare is a problem. For example, 

through the use of lenses and lighting controls, LED street and 

area lights, and step, path, and porch light luminaires can better 

distribute the light across the ground, allowing more uniform 

illumination. 

Refrigerated Display Cases; 

Retail Display; 

Street and Area Lights 

Battery Back-Up Capability - Traffic signals that include red, 

green, and yellow LEDs consume around one-tenth as much 

power and LED exit signs consume about one-fifth as much 

power as with incandescent sources. For this reason, battery 

back-up power supplies are available which can operate during 

power failures to ensure smooth flow of vehicular traffic or 

continuous delineation of building routes of egress. Many 

agencies use yellow LED signals for battery back-up reasons in 

emergency situations. For instance, if yellow LED signals were 

used in flashing mode, work crews would have a few extra hours 

to handle emergency situations (Bullough, 2003b). 

Traffic Signals and 

Pedestrian Crossings; 

Exit Signs 

Adjustable Color – Storeowners could also easily alter the 

intensity and color of the LED light to augment particular colors 

in the products. Recent marketing studies have shown that these 

features offer enhanced appeal to the human eye compared to 

other lighting systems. Study subjects strongly preferred display 

cases with LED lighting systems at half the illumination levels of 

fluorescent systems (Narendran, 2003b). 

Refrigerated Display Cases; 

Retail Display 

Light Pollution Reduction – The directional quality of LED street 

and area or step, path, and porch luminaires leads to more lumens 

to light the road plane or path and fewer lumens scattered 

upward, reducing light pollution. 

Street and Area Lights; 

Step, Path and Porch Lights 

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Table 1-2: LED Benefits in Addition to Energy Savings (continued) 

Benefit Applicable Niche Markets 

Competitive on First-Cost Basis – - Even on a first cost basis, 

which can be an important purchasing determinant, LED exit 

signs have become competitive. While incandescent signs 

without battery backup are still marginally less expensive than 

LED signs, the price for both types of signs with battery backup 

is about the same because the incandescent system requires a 

much larger battery. LED first costs have fallen in part due to 

the red LED being a relatively mature and well-understood 

technology. 

Exit Signs 

Fewer Accessories – Another benefit of LED holiday lights is 

that they require fewer extension costs, reducing raw material 

use of PVC and copper. Starting in 2008, the Underwriters 

Laboratory changed the regulations to allow more LED sets to 

connect end-to-end than incandescent sets. Now, as many as 43 

LED sets can be connected, end-to-end, compared to about 3-10 

sets of incandescent light strings (Altamura, 2008). 

Decorative Holiday Lights 

Mercury Reduction – Neon light sources contain mercury, a 

toxic substance that requires special handling for disposal. Neon 

signs contain as much as 300 mg of mercury, creating an 

environmental health and safety hazard for workers who shape 

the neon tubes (Vincent, 2008). In contrast, LEDs contain no 

mercury and require no special handling for disposal. 

Electric Signs 

Design Flexibility – The small size of LEDs and their mounting 

surface (generally the conductor cable supplying power) enable 

flexible arrangements in any desired pattern for electric signage. 

Electric Signs 

Ease of Installation and Maintenance – Skilled neon workers are 

required to install and repair neon signage. However, LEDs are 

more robust and flexible, and could be installed by general 

electrical and lighting contractors 

Electric Signs 

Increased product shelf life – LED sources radiate less heat than 

fluorescents, limiting the growth of bacteria thus increasing shelf 

life of meat products in refrigerated display cases. 

Refrigerated Display Cases 

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Table 1-2: LED Benefits in Addition to Energy Savings (continued) 

Benefit Applicable Niche Markets 

Enhanced product appearance – Jewelry lit by LED lamps 

appear to sparkle more brightly because an LED lamp contains 

multiple diodes which create many reflections off the jewel’s 

facets compared to a single incandescent or fluorescent bulb 

with equal lumen output. 

Retail Display 

Improved Color Rendition – Most LED street and area lighting 

products in the market have color temperatures of 3000-8000 K 

and color rendering indices of 70-85. With these color 

characteristics, LED street and area lights compare favorably 

with high pressure sodium lamps that have color temperatures 

of 1900-2200, providing a yellow/orange light, and color 

rendering indices as low as 23. 

Street and Area Lights 

Lower Lumen Depreciation – LEDs depreciate slowly over 

time in comparison with high intensity discharge (HID) lamps. 

The difference between HID initial and mean lumen output is 

significant, and leads to a lower efficacy over the lifetime of the 

HID lamp. 

Street and Area Lights 

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2. Colored-Light Applications 

LED sources began to penetrate colored-light applications in the early 1990s, with the 

incorporation of LEDs in traffic signal heads and building exit signs. In the early 2000s, due in 

part to technological improvements, reduced costs, and long operating lives (reducing 

maintenance costs), LEDs had already achieved significant penetration in these two markets, 

reaching 30-35% of the installed base for traffic signals and 80% of the installed base for exit 

signs (NCI, 2003). In 2007, penetrations of LEDs reached even higher levels due to a provision 

in the Energy Policy Act of 2005 (EPACT 2005) that required all new installations of traffic 

signal heads and building exit signs meet ENERGY STAR® requirements starting in January 2006, 

which can be met most cost-effectively with LEDs (ENERGY STAR, 2006). 

For this report, four colored-light applications were evaluated: traffic signals and pedestrian 

crossings, decorative holiday lights, exit signs, and electric signage. Colored-light LEDs are 

most commonly used in these applications, although white light is sometimes used as well. Exit 

signs have already saved 4.6 TWh of electricity due to the near saturation of LEDs in this 

application. Traffic signal heads have also achieved 52% LED market penetration, contributing 

to substantial energy savings. LED products are also available for decorative holiday lights and 

electric signage. These products are becoming more popular and are achieving higher market 

penetrations each year. 

2.1. Traffic Signals and Pedestrian Crossings 

LEDs have already begun to save substantial amounts of energy in traffic signal heads. Because 

of national market transformation initiatives, such as the ENERGY STAR® program and the 

Consortium for Energy Efficiency’s Energy-Efficient Traffic Signal Initiative, LEDs had already 

achieved significant penetrations in 2002. During the past five years, market penetration has 

increased even further due to favorable economics (ENERGY STAR, 2006) and due to the 

minimum efficiency standards established in EPACT 2005 requiring that all new installations 

meet ENERGY STAR® requirements after January 1, 2006. 

Estimated primary energy savings in 2007 from the current level of LED penetration into the 

traffic signal market is 30.4 TBtu per year. Nationally, it is estimated that if the remaining 

incandescent traffic signals were converted to LEDs, a further 21.9 TBtu per year of primary 

energy would be saved annually. Thus, if all of the previously incandescent traffic signals were 

converted to LED, approximately 5.2 TWh per year of electricity, or about 56.1 TBtu per year of 

primary energy would be saved. 

2.1.1. Introduction 

Traffic signals are an integral part of the transportation system in the United States, safely 

regulating the movement of vehicles and people. Installed primarily in urban areas, where 

vehicular and pedestrian traffic is concentrated, these signals operate 24 hours per day on a duty 

cycle that varies according to signal type. 

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For nearly the entire 20th century, traffic signals utilized incandescent light sources, as they were 

the only type of light source that could achieve the minimum performance requirements 

established by the Department of Transportation for light intensity. There are different 

performance standards for incandescent and LED traffic signals. However, in the past five to ten 

years, technology advances enabled LEDs to achieve the brightness, reliability, and control to 

compete in this niche market. In addition, EPACT 2005 required that all traffic signals 

manufactured after January 1, 2006 meet ENERGY STAR® energy consumption requirements of 

12-17 watts (ENERGY STAR, 2008), which can most cost-effectively be met with LEDs over the 

lifetime of the product (ENERGY STAR, 2006). 

Because of ENERGY STAR® requirements, LEDs are emerging as the technology of choice for 

traffic signal illumination. Municipalities all across the nation are retrofitting and installing new 

LED traffic signal heads. And, with continuing reductions in price and improvements in 

efficiency and performance, LED lamps offer a colored-light source that satisfies code 

requirements and displaces incandescent lamps. While they are initially more expensive than 

incandescent lamps, the long term cost savings and better quality of LEDs significantly outweigh 

the higher initial costs (Schmeltz, 2003). The market for traffic signals is clearly moving in the 

direction of LED light sources (Durgin, 2008). 

A number of sources were contacted to update the national energy consumption estimate from 

the 2003 edition of this report. As with the other niche market assessments, there are four 

critical inputs used in preparing the energy consumption and savings estimates, summarized in 

Table 2-1. Traffic signals considered in the analysis include: red colored ball, yellow colored 

ball, green colored ball, red arrow, green arrow, yellow bi-modal arrow, green bi-modal arrow, 

walking person, red hand – stop, and countdown signals. 

Table 2-1: Critical Inputs for Traffic Signals National Energy Consumption and Savings
 

Potential Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Signalized Intersections: Gary Durgin, Dialight, 

2008; Energy Savings Potential of LEDs in Niche Applications, 

NCI, 2003; Phillip Tarnoff, University of Maryland, 2008. 

Intersection Growth Rate: Estimated from U.S. Population 

growth between 2002 and 2007, U.S. Census Bureau; Ken 

Kobetsky, American Association of State Highway and 

Transportation Officials (AASHTO), 2008. 

Number of Pedestrian Signals: Gary Durgin, Dialight, 2008. 

Annual Operating Hours Estimates for Pedestrian Signals: U.S. Lighting Market 

Characterization, Volume I: National Lighting Inventory and 

Energy Consumption Estimate, Department of Energy, 2002a. 

Estimate for Three Colored-Ball Signals: Suozzo, 1997. 

Lamp Wattages Estimates of the Lamp Wattages: Gary Durgin, Dialight; Raj 

Ghaman, FHWA, 2008. 

Lighting Technology Mix Estimate of the Percent LED Penetration: Gary Durgin, Dialight, 

2008; Robert Steele and Vrinda Bhandarkar, Strategies 

Unlimited, 2008. 

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2.1.2. Traffic Signal and Pedestrian Crossing Installed Base 

In the United States, there are approximately 336,600 signalized intersections, representing a 

1.5% annual growth rate from the 2002 installed base of 312,500 signalized intersections 

published in the earlier edition of this report (NCI, 2003; Durgin, 2008; Tarnoff, 2008; Kobetsky, 

2008). At each intersection, up to three types of traffic signals, including the three-colored ball, 

arrow, and bi-modal arrow, can be found for the purposes of controlling traffic flow. In addition, 

approximately 75%, or about 252,450 intersections, also have pedestrian crossing signals 

(Durgin, 2008). The most common type of pedestrian crossing signal is the walking person and 

orange hand, although countdown pedestrian signals, implemented entirely with LEDs, have 

become more popular during the past five years. 

To determine the installed base of each type of signal, data were acquired in 2002 from existing 

studies, manufacturers, and the Institute of Transport Engineers (ITE). The collected data from 

each source were then averaged to obtain the estimated number of signals per intersection. This 

estimate was multiplied by the corresponding number of signalized or pedestrian-signalized 

intersections to approximate the total number of signals in the U.S. The 2002 installed base was 

multiplied by a 1.5% annual growth rate, an estimate obtained from manufacturers and industry 

experts (Durgin, 2008; Tarnoff, 2008; Kobetsky, 2008), for 5 years to obtain the 2007 installed 

base. Table 2-2 provides the average number of signals per intersection and the estimated total. 

Table 2-2: Estimated Number of Traffic Signals in the United States, 2007 

Signal Type Lamp Color Average Number per 

Intersection 

Estimated Number of 

Traffic Signals 

Red 9.7 3,265,000 

Yellow 9.7 3,265,000 

Three-Colored Ball 

Green 9.7 3,265,000 

Arrow Red 3 1,010,000 

Green 3 1,010,000 

Bi-Modal Arrow Yellow 1 336,500 

Green 1 336,500 

Walking Person White 8 2,019,500 

Hand Orange 8 2,019,500 

Countdown Red 0.21 53,000 

Total 16,527,000 

2.1.3. Traffic Signal and Pedestrian Crossing Operating Hours 

Traffic signals operate 24 hours per day year-round, amounting to an annual operating cycle of 

8,760 hours. Among these signals, less than two percent change to flashing mode for four to six 

hours at night (Larocca, 2003). For this reason, the impact of flashing time on a traffic signal’s 

operational time is fairly negligible and thus signals are treated as being continuously on. In 

three-colored ball signals, the red lamp is illuminated 55% of the time over a 24-hour period, the 

green lamp 42%, and the yellow lamp 3% (Suozzo, 1998). Red and green arrows are estimated to 

operate approximately 9% of the time (DOE, 2002a). The analysis models “walk” and “don’t 

walk” pedestrian signals to be off half the time, on for one-quarter, and flashing for one-quarter 

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of the time (DOE, 2002a). Thus, pedestrian signals, such as white walking people and orange 

hands, are each illuminated about 31% of the time, or 7.5 hours per day (DOE, 2002a). In 

addition, we estimate countdown signals to be illuminated for 12% of the time, or 2.8 hours per 

day, however these signals do not contribute to energy savings as they are a new application for 

LEDs. The corresponding operating hours per year for each signal type and lamp color are 

presented in Table 2-3. 

Table 2-3: Traffic Signal Operating Hours by Lamp Type and Color 

Signal Type Lamp Color Utilization Factor Operating Hours 

(hours/yr) 

Red 55% 4,818 

Yellow 3% 263 

Three-Colored – 

Ball 

Green 42% 3,679 

Arrow Yellow 9% 815 

Green 9% 815 

Bi-Modal Arrow Red 9% 815 

Green 9% 815 

Walking Person White 31% 2,716 

Hand Orange 31% 2,716 

Countdown Orange 12% 1,051 

2.1.4. Traffic Signal and Pedestrian Crossing Lamp Average Wattages 

Because they operate by shining full-spectrum light through a colored filter, incandescent lamps 

consume the same energy regardless of the color of the signal ball or arrow. As there are 

different luminous intensity standards for different diameter signals, the size of the signal ball 

(generally standardized around 8 and 12 inch diameters) will impact the wattage of the lamp, and 

thus the energy consumption (ITE, 2005; Bullough, 2003a). Nationally, it is estimated that about 

75% of three-colored ball signals are 12-inch and the remainder are 8-inch (Durgin, 2008). 

Incandescent arrow and pedestrian signals are typically 12-inch. 

LED light sources produce colored light (no color filter required), and the operating wattage does 

vary with light color, as the LED chip is made of different materials which produce the different 

colors. Incandescent and LED wattages from manufacturers were used to prepare average 

wattages for this analysis. The findings are presented in Table 2-4 along with the weighted 

average of the 8-inch and 12-inch wattages for each type and color of traffic signal (Durgin, 

2008). 

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Table 2-4: Traffic Signal Wattage for Incandescent and LED Lamps by Color 

Incandescent Wattage LED Wattage 

Signal Type Lamp 

Color 8 inch 12 inch Avg. 8 inch 12 inch Avg. 

Red 78 135 121 6 8 8 

Yellow 78 135 121 12 20 18 

Three-Colored – 

Ball 

Green 78 135 121 8 9 9 

Arrow Red - 132 132 - 7 7

Green - 132 132 - 9 9 

Bi-Modal Arrow Yellow - 132 132 - 12 12 

Green - 132 132 - 9 9 

Walking Person White - 132 132 - 8 8 

Hand Orange - 132 132 - 8 8 

Countdown Orange - - - - 9 9 

In 2005, the Institute of Transportation Engineers (ITE) passed a wattage standard of 69 watts for 

8-inch incandescent signal balls and 120 watts for 12-inch incandescent signal balls to set an 

acceptable level of brightness required to maintain driver safety and limit energy consumption. 

We estimate that all incandescent traffic signal replacements and new construction of traffic 

signals follow the ITE standard after 2005, amounting to 23% of the installed base of traffic 

signals.

10 The ITE standard lowers the average wattage of the installed base of traffic signal 

heads shown in Table 2-4 from the averages of 81 watts for 8-inch signal heads and 140 watts for 

12-inch signal heads published in the 2003 edition of this report. In addition, in August 2005, 

the President signed the Energy Policy Act (EPACT) of 2005, mandating that all traffic signals 

manufactured after January 1, 2006 meet ENERGY STAR® requirements, which can most costeffectively be met with LEDs (ENERGY STAR, 2006). The estimates of the percent LED 

penetration of traffic signals, shown in Table 2-5, take into account the impact of EPACT 2005. 

2.1.5. Traffic Signal and Pedestrian Crossing Energy Saving Potential 

Market penetration of LED traffic signal and pedestrian crossings has increased to approximately 

52% of the market due to the energy saving benefits and reduced maintenance costs of the 

technology, as well as market transformation programs highlighting these advantages and the 

requirements of EPACT 2005 (Durgin, 2008). Red signal heads have seen the highest level of 

LED market penetration at 65%, while green signal heads are approximately 59% LED (Durgin, 

2008, Bhandarkar, 2008). Because of their low duty-cycle, yellow LED traffic signals have a 

much longer payback period. This, coupled with the stringent luminosity specifications for 

yellow LED signals (Bullough, 2003a) results in a lower market penetration, estimated to be 

around 25%. Table 2-5 outlines the market penetration by type and lamp color (Durgin, 2008). 

10 We assume an average traffic signal fixture lifetime of 15 years to develop the estimate of ITE-standard-compliant 

traffic signals. 

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Table 2-5: Traffic Signal Percent LED Penetration by Type and Lamp Color 

Signal Type Lamp Color Installed Base of 

LED Signals 

Three-Colored Ball Red 65%

Yellow 25%

Green 59%

Arrow Red 60%

Green 59%

Bi-Modal Arrow Yellow 60%

Green 60%

Walking Person White 50% 

Hand Orange 50% 

Countdown Red 100% 

Total 52% 

With 52% market share, more than 8.5 million traffic signals already use LED sources while 8.0 

million have not yet been converted. Table 2-6 describes the installed base of incandescent and 

LED traffic signals and their corresponding energy consumption. 

Table 2-6: Traffic Signal Energy Consumption and Savings Estimate, 2007 

Potential Theoretical Annual Electricity Niche Electricity Maximum 

Application Electricity 2007 Savings 2007 Savings Electricity Savings (TWh/yr) (TWh/yr) (TWh/yr) (TWh/yr) 

Red colored ball 0.74 1.16 0.63 1.79 

Yellow colored ball 0.08 0.02 0.07 0.09 

Green colored ball 0.66 0.80 0.55 1.35 

Red arrow 0.05 0.06 0.04 0.10 

Green arrow 0.05 0.06 0.04 0.10 

Yellow bi-modal arrow 0.02 0.02 0.01 0.03 

Green bi-modal arrow 0.02 0.02 0.01 0.03 

Walking person 0.38 0.34 0.34 0.68 

Red hand – stop 0.38 0.34 0.34 0.68 

Countdown 0.001 0.00 0.00 0.00 

Total: 2.38 2.82 2.03 4.85 

The increasing penetration of LEDs in traffic signal and pedestrian crossings has decreased this 

application’s electricity consumption by 7% per year and increased its annual electricity savings 

since 2002. In 2002, traffic signals and pedestrian crossings yielded an electricity savings of 

1.48 TWh/year. At the current level of LED penetration, traffic signal and pedestrian crossings 

have yielded 2.82 TWh/yr of energy savings, decreasing this application’s national energy 

consumption from 5.20 TWh/yr (what it would have been if all installations were incandescent) 

to 2.38 TWh/yr. Converting the remaining stock of incandescent traffic signals to LED will save 

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an additional 2.03 TWh/yr. In terms of primary energy consumption, 30.4 TBtu/yr of energy is 

saved from existing market penetration, and a further 21.9 TBtu/yr of energy could be saved if 

the remainder of incandescent traffic signals convert to LEDs. Considering both present and 

future energy savings, traffic signals could save approximately 4.85 TWh/year, or over 76% of 

the annual output of one large (1,000 MW) electric power station. This amount of electricity 

represents the annual electricity consumption of four hundred thousand typical U.S. households. 

2.1.6. Technology Benefits in Addition to Energy Savings 

There are several benefits outside of energy savings that are driving the adoption of LED 

technology in the traffic signal and pedestrian crossing application. In addition to saving more 

than 30.4 TBtu per year, and potentially a further 21.9 TBtu when the market reaches saturation, 

LED traffic signals offer other advantages over traditional incandescent traffic signals. These 

include: 

1. Longer Operating Life 

2. Lower Maintenance and Life-Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Durability 

6. Safety Improvements 

7. Color Maintenance 

8. Battery Back-Up Capability 

For more information about these additional LED benefits, refer to Table 1-2. 

2.2. Decorative Holiday Lights 

Even though the holiday season is just a few weeks of the year, the conversion of holiday lights 

from incandescent to LED sources would generate considerable energy savings. The potential 

annual energy savings of a complete market shift to LED holiday lights is approximately 64.4 

TBtu of primary energy consumption, equivalent to the output of ninety percent of one large 

(1000 MW) electric power plant or the annual electricity consumption of almost five hundred 

thousand households. Along with significant energy savings, the adoption of LED sources would 

be accompanied by other benefits, including a longer operating lifetime as well as a safer and 

more durable product. 

2.2.1. Introduction 

Holiday lights serve an aesthetic function, using colored and white light to build a certain mood 

or evoke positive feelings and emotions. Most holiday lights operate for a limited part of the 

year, typically around the holiday season from late November to early January. These lights can 

be found donning the one hundred million real and artificial holiday trees on display annually in 

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the U.S. (UIE, 2005) as well as decorating the exteriors of residential and commercial 

buildings.11 The lights, a symbol of the yuletide season, are also commonly used at shopping 

malls, store displays, city streets, or hotel and motel decorations. When used in these 

applications, operation can span the whole year, and not just the holiday season. 

Due to their intermittent annual use, energy efficiency has not been a significant market driver. 

Historically, users who wanted to control the energy consumption would move to smaller, lower 

wattage lamps, fewer light strings, or use timers to regulate on-time. Now, energy-saver 

incandescent light strings are available offering over 40% of the energy savings of regular 

incandescent light strings and LED holiday lights are available offering 90% energy savings per 

bulb. Due to their natural aptitude to produce a spectrum of colored light, depending on the chip 

substrate, LED technology is well suited to this application and may gradually replace 

conventional incandescent lights over time, saving significant energy and money. 

A number of sources were consulted to prepare a national energy consumption estimate. As with 

the other niche market assessments, there are four critical inputs used in preparing the energy 

consumption and savings estimates, summarized in Table 2-7. 

Table 2-7. Critical Inputs for Holiday Lights National Energy Consumption and Savings
 

Potential Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Holiday Light Inventory: Unites States International Trade 

Commission (USITC), 2005-2007. 

Annual Operating Hours Operating Hour Estimate: Decorative Light String Market 

Assessment Report, prepared by Navigant Consulting, 2006. 

Lamp Wattages Lamp Wattage Estimate: David Allen, Forever Bright, 2008; 

Steve Altamura, Seasonal Specialties, 2008; Washington State 

University (WSU), 2007 

Lighting Technology Mix LED Market Penetration Estimate: David Allen, Forever 

Bright, 2008; Steve Altamura, Seasonal Specialties, 2008. 

2.2.2. Decorative Holiday Lights Installed Base and Operating Hours 

There are many different types of holiday lights, such as miniature, icicle, sphere, G30, G40, 

flame-tip, micro, button, pearl light, C-6, C-7, and C-9 lights, each of which differ slightly in 

bulb size and lamp wattage. LED replacements exist today for incandescent miniature, icicle, 

C-6, C-7 and C-9 light strings. As there is virtually no domestic production of holiday lights 

(Allen, 2008; Altamura, 2008), it was assumed for this analysis that all holiday lights are 

imported. The United States International Trade Commission (USITC) tracks the imports of 

“lighting sets of a kind used for Christmas trees,” of which, approximately 122.9 million sets are 

imported each year (USITC, 2005-2007). Of this total, the estimated number of imported 

miniature light sets (including icicles) is 98.4 million per year, or about 80% of total holiday 

11 The number of holiday trees in the U.S. is based on annual sales of 32.8 million real trees in 2005, and the 

estimate that in 2002, 21% of U.S. households had a real tree, 48% had an artificial tree and 32% had no tree, 

assuming the same proportions in 2007. 

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light imports (USITC, 2007). These are average values from the past three years, as shown in 

Table 2-8, below. The remaining imported lights are a combination of all other types of holiday 

lamps (C-6, C-7, and C-9). 

Table 2-8: Imports of Holiday Lights, 2005-2007 

Lights 2005 2006 2007 Three Year Average 

Imports of Miniature Lights 99,951,000 91,845,000 103,344,000 98,380,000 

Imports of Other Lights 20,150,000 30,137,000 23,176,000 24,488,000 

Total Imports 120,101,000 121,982,000 126,520,000 122,868,000 

Table 2-9: Operating Hours for Holiday Lights 

Application Residential Use (90%) Commercial Use (10%) 

Primary Application (75 %) 180 to 360 hours 540 to 720 hours 

Secondary Application (25 %) 180 to 450 hours 4,380 hours 

Average 272 hours 818 hours 

Weighted Average 410 hours 

The installed base of miniature holiday lights can be estimated by considering the typical lifetime 

of the lamps, which determines how long a particular string may remain in service. The typical 

lifetime of a string of miniature lights is three years (DOE, 2002b; Bruno, 2003). This estimate is 

based on the assumption of 90% residential use and 10% commercial use, and 75% seasonal 

(primary application) use and 25% extended (secondary application) use, operating at the 

average of 9 hours of operation per day, 45 days a year, or 410 hours per year (NCI, 2006; Allen, 

2008; Altamura, 2008). This operating hour estimate is higher than the 2002 estimate of 150 

hours per season, because of the inclusion of commercial-use holiday light strings in this year’s 

report. 

After 3 years, or about 1200 hours, approximately one third to one half of the bulbs will have 

failed, resulting in the disposal of the entire string (Altamura, 2008). Multiplying the average 

annual sales over the past three years by the three-year typical lifetime yields an installed base of 

368 million holiday light strings of which 295 million are miniature or icicle light strings. We 

assume that miniature and icicle holiday lights contain 100 lamps per string, C-6 light strings 

contain 35 lamps, while C-7 and C-9 strings contain 25 lamps each. Thus, the installed base of 

holiday lamps is about 31.5 billion of which 27.9 billion are miniature or icicle lamps. This 

estimate is lower than the installed base of 37.1 billion miniature lamps in 2002, as annual sales 

of holiday lights have been declining. 

2.2.3. Decorative Holiday Lights Energy Saving Potential 

The annual energy consumption of holiday lights can be estimated as the product of the installed 

base, the operating hours, and the wattage of each light string. Table 2-10 shows the estimated 

market share and wattages of conventional, energy-saver, and LED holiday lights. Energy saver 

lamps consist of approximately a third of all incandescent holiday lights sold (Altamura, 2008). 

Our methodology differs from the earlier edition of this report in that commercial sector holiday 

lights, secondary application, and energy-saver incandescent light strings are included in the 

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analysis, and C-6, C-7, and C-9 energy consumption and savings are provided as LED light 

strings have become available for these products during the past five years. As a result of 

including higher-wattage non-miniature light strings and commercial sector and secondary 

application holiday lights with longer operating cycles in the analysis, energy consumption and 

savings of holiday lights will be greater than in 2002, despite the overall decline in holiday light 

sales. 

Table 2-10: Conventional and LED Holiday Light Lamp Average Wattage 

Type 

Market 

Share 

(%) 

LED 

Penetration 

(%) 

Incandescent 

Light String 

Wattage (W) 

Energy Saver 

Incandescent 

Light String 

Wattage (W) 

Average 

Incandescent 

Light String 

Wattage (W) 

LED Light 

String 

Wattage (W) 

C-9 Lights 5.0% 1.0% 175 125 159 2.5 

C-7 Lights 7.0% 5.0% 100 75 92 2.5 

C-6 Lights 8.0% 10.0% 36 NA 36 0.9 

Miniature & 

Icicle Lights 

80% 5.0% 42 24 36 5.0 

Total 100% 5.2% 62 40 55 4.4 

Over the past five years, LEDs have started to carve a small niche in the holiday light market. 

LEDs have significant benefits, such as operating lifetimes more than 30 times longer12 than 

traditional miniature lights and 90 % lower energy consumption per lamp. Based on 

manufacturers’ sales of LED holiday light strings to major retailers, we estimate that LEDs have 

a market penetration of 5.2% (Allen, 2008), compared to minimal market penetration of LEDs in 

2002. 

Table 2-11: Holiday Lights Energy Consumption and Savings Estimate, 2007 

Annual Electricity Potential Theoretical Maximum 

Application Electricity 2007 Savings 2007 Electricity Savings Electricity Savings 

(TWh/yr) (TWh/yr) (TWh/yr) (TWh/yr) 

C-9 Lights 1.13 0.06 1.11 1.18 

C-7 Lights 0.92 0.05 0.89 0.94 

C-6 Lights 0.41 0.02 0.40 0.43 

Miniature & Icicle 

Lights 4.14 0.23 3.56 3.78 

LED Holiday Lights 0.03 - - -

Total 6.63 0.33 5.97 6.30 

In 2007, the current level of LED penetration yielded 0.33 TWh/yr of site electricity savings, 

compared to minimal energy savings in 2002. If the market shifted entirely to LED holiday 

lights, a potential 5.97 TWh per year could be saved. The 2007 energy savings potential of 5.97 

TWh per year is equivalent to 64.4 TBtu per year of primary energy savings, the output of ninety 

percent of one large (1000 MW) electric power plant or the annual electricity consumption of 

almost five hundred thousand households. A theoretical maximum energy savings (2007 energy 

12 This lifetime claim is based in manufacturer product literature. However, ENERGY STAR requires only a 3-year 

warranty for an LED light string under normal residential use. 

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savings plus energy savings potential) of 6.30 TWh per year is possible if the market converted 

entirely to LED holiday light strings. 

2.2.4. Technology Benefits in Addition to Energy Savings 

In addition to the dramatic energy savings potential identified in Table 2-11, there are other 

benefits to end-users from selecting LED holiday lights. 

1. Longer Operating Life 

2. Lower Maintenance and Life Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Durability 

7. Safety Improvements 

8. Color Maintenance 

9. Fewer Accessories 

For more information about these additional benefits of LEDs, refer to Table 1-2. 

2.3. Exit Signs 

Since their introduction in 1985, LED exit signs have become the most common type of exit sign 

installed because of lower energy consumption and lower maintenance costs than other types of 

lighting. National promotional initiatives such as ENERGY STAR® have helped to raise business 

awareness and expand market penetration. In addition, EPACT 2005 included a provision that 

mandated that all exit signs installed after January 1, 2006 must be compliant with ENERGY 

STAR® requirements that exit signs consume no more than 5 Watts per face, which can most 

cost-effectively be met with LEDs (ENERGY STAR, 2007b). In terms of primary energy savings, 

49.2 TBtu per year are currently saved from existing LED exit signs, and a further 6.8 TBtu of 

savings could be captured if the remaining conventional sources in the installed base were to 

switch to LED. In total, the energy savings from 100% market saturation with LED exit signs 

would be approximately 55.9 TBtu per year. 

2.3.1. Introduction 

Buildings designed for public occupancy require exit signs that continuously operate to 

demarcate routes of egress in the event of an emergency. Building safety standards mandate 

certain performance requirements for those exit signs; for example, self-luminous signs must 

have a minimum of 0.06 foot lamberts (0.21 candelas per square meter) (DOL, 2002). For many 

years, exit signs relied on incandescent light sources to achieve visibility requirements. However, 

in the last 20 years, other sources such as compact fluorescent and LED have become in use, due 

to their lower life-cycle costs. 

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Today, LEDs have emerged as the technology of choice for exit sign illumination. Thanks in part 

to the technology advancements of the last two decades, the LED has become a highly reliable, 

energy efficient colored-light source that satisfies code requirements while reducing energy 

consumption and maintenance costs. LEDs offer more favorable economics, better performance, 

and enhanced safety capabilities than conventional exit signs. 

To prepare a national estimate of the energy savings potential of LED exit signs, estimates of the 

installed base, operating hours, and average wattage were assembled. These estimates draw upon 

publicly available literature as well as consultative interviews with manufacturers and industry 

experts. As with the other niche market assessments, there are four critical inputs used in 

preparing the energy consumption and savings estimates, summarized in Table 2-12. 

Table 2-12. Critical Inputs for Exit Signs National Energy Consumption and Savings Potential
 

Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Exit Signs: U.S. Lighting Market Characterization, 

Volume I: National Lighting Inventory and Energy 

Consumption Estimate, DOE, 2002a. 

Commercial Floorspace Growth Rate: Commercial Building 

Energy Consumption Survey (CBECS), 2003, 1999. 

Industrial Floorspace Growth Rate: Manufacturing Energy 

Consumption Survey (MECS), 1998, 1994. 

Annual Operating Hours Exit signs operate continuously: 8,760 hours per year. 

Lamp Wattages Estimates of the Lamp Wattages: PG&E, 2000; Efficiency 

Maine, 2003; E-Source, 2002; Virginia Department of Mines 

and Minerals, 1998; Light Panel, 2003; ENERGY STAR®, 2008. 

Lighting Technology Mix Estimate of the Percent LED Penetration: NEMA, 2003; Robert 

Steele and Vrinda Bhandarkar, Strategies Unlimited, 2008; 

Cheryl English, Acuity Brands, 2008. 

2.3.2. Exit Signs Installed Base 

The 2007 installed base of exit signs is the product of the growth rate of exit signs from 2002-

2007 and the exit sign inventory estimate published in the previous edition of this report, which 

is derived from the U.S. Lighting Market Characterization Volume I: National Lighting 

Inventory and Energy Consumption Estimate (DOE, 2002a). This study takes building audit and 

sub-metering data on lighting in commercial and industrial buildings and extrapolates the 

information to the nation as a whole, based on the building inventories published by the Energy 

Information Administration. Exit signs were one of the lighting fixtures tracked in the building 

audits conducted in the 1990s, which numbered more than 25,000 buildings. 

The growth rate of exit signs from 2002 to 2007 is proportional to the growth rate of building 

floorspace during this period. The 1.6% annual growth rate of commercial floorspace was 

determined from the 2003 and 1999 Commercial Building Energy Consumption Survey, 

published by the Energy Information Administration (EIA). The 1.0% growth rate of industrial 

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floorspace was determined from the 1998 and 1994 Manufacturing Energy Consumption Survey, 

also published by the EIA. Extrapolating the 2002 exit sign inventories from the earlier edition of 

this report, by building type, to a national level produces an estimated installed base of 

approximately 35.6 million exit signs in 2007, shown in Table 2-13(DOE, 2002a). Since 2002, 

the U.S. has added about 2 million exit signs. 

Table 2-13: Number of Exit Signs in the United States, 2007 

Sector Estimated Number of Exit Signs 

Commercial Exit Signs 31,893,000 

Industrial Exit Signs 3,743,000 

Total National Inventory 35,636,000 

Due to highly favorable economics, better performance, enhanced safety capabilities, marketing 

programs such as ENERGY STAR® Exit Signs, and EPACT 2005 provisions that all new exit sign 

installations manufactured after January 1, 2006 meet ENERGY STAR® requirements that exit 

signs consume no more than 5 watts per face, over 85% of exit signs incorporated LEDs in 2007. 

Less than five percent of exit signs are still incandescent, and the remaining ten percent are 

compact fluorescent. There are already more than 30 million LED exit signs while only about 

1.6 million incandescent and 2.7 million compact fluorescent exit signs remain in the market. 

Table 2-14 presents available estimates of the most recent shipment apportionments and 

estimates of the installed base from an industry expert (English, 2008). 

Table 2-14: 2007 Exit Sign Percent Market Share by Lamp Type 

Source Shipment Estimate, 2007 Estimated Installed Base 

Incandescent 0 percent 4.6 percent 

Compact Fluorescent 0 percent 9.7 percent 

Light Emitting Diode 100 percent 85.7 percent 

2.3.3. Exit Signs Operating Hours 

Exit signs, by building safety code requirement, operate 24 hours per day year-round, amounting 

to an annual operating cycle of 8,760 hours. 

2.3.4. Exit Signs Lamp Average Wattages 

The wattage of installed exit signs varies both by the light source (e.g., incandescent, compact 

fluorescent, LED) and within a given light source. For example, incandescent exit signs can be 

found which range between 10 and 50 watts for a two-sided sign (LightPanel, 2003; ENERGY 

STAR, 2008) and LED fixtures can be found between 2W and 10W, also for two-sided signs. For 

this application, LED sources produce light in the color spectrum required (e.g., red or green). 

This method differs from that of incandescent or compact fluorescent light sources, which 

produce full-color spectrum light, and then have a color filter that absorbs all the colors except 

red or green. Table 2-15 provides the range of wattages identified for each light type, along with 

an estimated average value used in the energy savings calculation. 

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Table 2-15: Exit Sign Wattage by Lamp Type 

Source Low High Estimated Average 

Incandescent 10 watts 50 watts 32 watts 

Compact Fluorescent 10 watts 24 watts 17 watts 

Light Emitting Diode 2 watts 10 watts 6 watts 

2.3.5. Exit Signs Energy Saving Potential 

LED exit signs with an average luminaire efficacy of 45.5 lm/W13 contributed 4.56 TWh of 

energy savings in 2007, using a baseline exit sign installed base of 37% incandescent and 63% 

CFL exit signs (the presumed technology mix of the exit sign market with no LED penetration). 

If the entire exit sign installed base converted to LEDs, an additional 0.63 TWh of energy can be 

saved yielding a theoretical maximum energy savings potential of 5.18 TWh/yr due to LEDs, 

equal to over 70% of the annual output of one large (1000 MW) electric power plants or the 

annual electricity consumption of over three hundred thousand households. The primary energy 

savings of LED exit signs in 2007 amounts to 49.2 TBtu/yr with a further 6.78 TBtu of annual 

primary energy savings potential. Thus, in total, 55.9 TBtu/yr in primary energy savings could 

be captured if 100% of the installed base moved to LED. If the 2007 baseline of exit signs had 

been entirely incandescent, LEDs would have yielded 7.49 TWh of electricity savings, compared 

to 6.86 TWh of electricity savings in 2002. 

Table 2-16: Exit Sign Energy Consumption and Savings Estimate, 2007 

Theoretical Annual Electricity Potential Maximum Application Electricity 2007 Savings 2007 Electricity Savings Electricity Savings (TWh/yr) (TWh/yr) (TWh/yr) (TWh/yr) 

Exit Signs 2.50 4.56 0.63 5.18 

13 The average efficacy for LED exit signs was estimated by dividing the average lumen output of an equivalent 

CFL or incandescent sign by the average wattage of an LED sign (6 watts). This assumes that LED exit sign 

luminaires produce an equivalent amount of lumens as the mix of CFL and incandescent exit signs. However, this 

assumption does not impact the energy consumption and savings potential calculations, which are based on the 

estimated average wattage of LED vs. incandescent or CFL exit signs. 

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2.3.6. Technology Benefits in Addition to Energy Savings 

There are several additional benefits beyond energy savings that are driving the market to adopt 

LED exit signs, as described in greater detail in Table 1-2. In addition to saving about 55.9 TBtu 

per year, and potentially a further 6.78 TBtu when the market reaches saturation, LED exit signs 

offer advantages over traditional exit signs that compel building owners and managers to shift to 

LED sources. These include: 

1. Longer Operating Life 

2. Lower Maintenance and Life Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Durability 

6. Safety Improvements 

7. Color Maintenance 

8. Battery Back-Up Capability 

9. Competitive on First-Cost Basis 

2.4. Electric Signage 

Electric advertising signage has become increasingly popular during the past five years, reaching 

6.1% market penetration in 2007. The energy that would be saved if 100% of the installed base 

of neon signs switched to LED is approximately 81.3 TBtu of primary energy, equivalent to the 

output of one large (1000 MW) coal power station or the annual electricity consumption of six 

hundred thousand households. 

2.4.1. Introduction 

Advertising signs play an important role in our national economy, helping customers to locate 

retailers and service providers, identify products they may want to buy, or simply determine if a 

shop is open for business. Colorful, actively lit signage attracts the attention of customers and 

works to generate business for the establishment. Historically, advertising signs have relied on 

incandescent, fluorescent, or neon light sources for illumination. Recently, LED sources have 

started making inroads into this market, gradually replacing the traditional sources, particularly 

neon. 

According to a 2007 state of the industry report published by Signs of the Times magazine 

(STMG), the number of companies offering signs that incorporate LED technology is increasing, 

as are the shipments of electric signs based on this light source (STMG, 2008a). The 

publication’s survey of manufacturers found that in 2007 approximately 89% of electric signage 

companies offered products that incorporate LED illumination sources, up from 48% in 2002. 

The survey also found that shipments of electric signs that incorporate LED sources increased 

from 6.2% to 23.4% of total shipments over the same time period, a 277% increase. At the same 

time, shipments of neon and fluorescent electric signs decreased slightly (STMG, 2008). For the 

first time in 2007, Signs of the Times found through its annual online Lighting Survey that 30.2% 

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of electric signs sold by respondent companies were LED, surpassing the 22.8% share of neon 

signs sold (STMG, 2008b). These surveys show that LEDs, along with fluorescents, are 

becoming the technologies of choice for electric signage. 

The energy savings estimate is based on LED replacement of electrically-lit neon signage. The 

electric signs encompassed in this estimate include shaped neon-tube channel letter signs, reverse 

channel letters, and border lighting. Other types of electric signs are not considered because 

suitable LED replacements do not yet exist. One of the advertising options offered by LED 

sources is outdoor video screens and message display boards. In applications such as the 

NASDAQ building in Times Square, New York, LEDs enable advertisers to actively engage 

their audience through video monitors and digital displays with news and other moving images 

presented in color on a billboard-sized screen. For this energy savings estimate, however, LED 

billboard screens are not considered, as this new application represents an increase in energy 

consumption over traditional billboards which in many cases use no energy. 

There is no single published study available of energy consumption for electric signs; therefore a 

number of sources were contacted to prepare a national energy consumption estimate. As with 

the other niche market assessments, there are four critical inputs used in preparing the energy 

consumption and savings estimates, summarized in Table 2-17. 

Table 2-17. Critical Inputs for Electric Signage Energy Consumption and Savings Potential
 

Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Electric Signs: Annual Survey of Manufacturers, U.S. 

Census; 1992-2006, Signs of the Times Magazine (STMG), 2004; 

SignCraft, 2003. 

Percentage of Neon and LED Sign Shipments: Signs of the Times 

Annual State of the Industry Report, 2007. 

Average Sign Price: Interface Signs, Commercial Signs. 

Annual Operating Hours Estimates for Operating Hours: Signweb; Bryan Vincent, AgiLight, 

2008. 

Lamp Wattages Estimates of LED Lamp Wattages: J. Bryan Vincent, AgiLight, 2008; 

Jill Bonilla and Jim Sloan, SloanLED, 2008. 

Estimates of Neon Wattages: J. Bryan Vincent, AgiLight, 2008; 

Universal Lighting, 2003. 

Estimate of LED efficacies: J. Bryan Vincent, 2008, Jill Bonilla, 

2008. 

Lighting Technology Mix Estimate of the Percent LED Penetration: Signs of the Times Annual 

State of the Industry Report, 2008. 

2.4.2. Electric Signage Installed Base, Operating Hours, Wattage 

The number of electric signs sold per year, and presumably displayed, can be calculated by 

taking the total annual sales of the electric signage industry and dividing by an average electric 

sign price. In addition, electric signs were assumed to have an average operating life of 15 years 

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 -

 

 –

(D&R, 2003). Thus, the estimated installed base is the summation of the total number of electric 

signs sold in that time period (1993-2007). 

The annual sales figures of electric signs were available from two different sources: the 

Department of Commerce’s Annual Survey of Manufacturers (ASM) and from a sign industry 

trade magazine, Signs of the Times. For years when estimates from both the ASM and Signs of 

the Times magazine were available, an average was taken to prepare the estimate of installed 

base of electric signage; otherwise, the ASM value was used. The ASM provides annual sales 

data from 1993 to 2007, but another trade magazine, Sign Craft, estimates that the value reported 

by the ASM is actually only 50% of total sales of all sign shops (SignCraft, 2003). As a result, 

the ASM sales numbers were multiplied by two for this estimate. The second source, the Signs 

of the Times magazine conducts an annual industry survey of the electrical signage retailing 

industry. Analysts from this magazine who have studied these annual surveys prepared an 

estimate of the installed base of commercial advertising electric signs in the U.S. 

After speaking to a number of sign manufacturers, an average price per sign of $5,000 was 

selected in 2003. It was assumed the average sign price was constant over the fifteen-year 

period, adjusted for inflation, yielding a 2007 average price per sign of $5,600. The installed 

base is given in Table 2-18. 

Table 2-18: Electric Signs Annual Sales, Average Price, and Estimated Installed Base, 2007 

Total Sales Total Sales ASM, Inflation Adjusted % Difference Estimated # of Year Signs of the Times Sign Craft Average in Sources Signs Sold ($Billion) ($Billion) Sign Price ($) 

1993 3.39 2.75 23% $3,890 790,000 

1994 3.70 3.23 15% $4,010 864,000 

1995 4.10 3.55 16% $4,120 928,000 

1996 4.30 3.88 11% $4,240 964,000 

1997 4.60 4.12 12% $4,340 1,005,000 

1998 5.00 3.79 32% $4,450 988,000 

1999 5.40 5.03 7% $4,520 1,154,000 

2000 5.60 4.84 16% $4,620 1,130,000 

2001 5.40 4.79 13% $4,780 1,066,000 

2002 5.10 5.16 -1% $4,920 1,042,000 

2003 5.10 5.33 -4% $5,000 1,043,000 

2004 -- 5.60 0% $5,110 1,096,000 

2005 -- 6.28 0% $5,250 1,196,000 

2006 -- 7.05 0% $5,430 1,299,000 

2007 -- est. 7.35 0% $5,600 est. 1,313,000 

Total Installed: 15,878,000 

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Table 2-19: Electric Signs Percent Market Share by Lamp Type 

Estimated Installed Light Source Shipments, 2007 Base, 2007 

Neon 33.4 percent 42.1 percent 

Fluorescent 47.7 percent 45.8 percent 

LED 23.4 percent 6.1 percent 

Other 5.5 percent 6.1 percent 

The installed base of 15.9 million electric signs represents all electric signs, including signs 

illuminated from neon, fluorescent, HID, and fiber optic sources. Since currently, LED 

replacements only exist for neon signs, the potential market that is suitable for replacement is 

actually much smaller, about 7.6 million electric signs. Along with annual sales figures, Signs of 

the Times magazine also provides information on how electric signs are illuminated, classified by 

lighting type. Table 2-19 shows the estimated shipments and installed base of electric signs by 

lamp type, projected from annual electric sign shipments reported in Signs of the Times’ annual 

“Electric Sign State of the Industry” reports from 2001 to 2007 (STMG, 2003-2008). The neon 

lamps illuminating these signs could be replaced by LEDs. The “Other” category includes 

electric signs illuminated by incandescents, fiber optics, and other technologies for which good 

LED replacements do not yet exist. 

The term “neon” actually refers to more than just neon gas and generally extends to include any 

inert gas that emits color when ionized. Different gases produce different colors: neon glows 

bright red, and a mix of argon and mercury creates a blue/white color. The average wattage per 

foot of LED strip is 0.96W (GELcore, 2003; SloanLED, 2002; Vincent, 2008). The average 

nominal installation for a sign is 150 feet (Vincent, 2008; SloanLED, 2003). Channel letter signs 

are assumed to operate 10 hours per day, 365 days per year. Thus, the operating hours for 

channel letter lighting are estimated to be 3,650 hours per year (Vincent, 2008). 

Table 2-20: Electric Sign Installed Base, Operating Hours, and Power Consumption 

Source 

Operating Average Nominal Power 

Installed Base Hours Wattage Installation Consumption 

(units) (hours/yr) (W/ft.) (feet) per Sign (W) 

LED 913,000 3,650 0.96 150 180 

Neon 6,711,000 3,650 3.0 150 450 

Total 7,624,000 3,650 -- 150 --

2.4.3. Electric Signage Energy Saving Potential 

The current market penetration of LEDs into channel letter signs is estimated to be 6.1% percent, 

based on the technology mix of annual shipments of electric signs from 2001-2006. Table 2-21 

presents the energy consumption estimate for neon commercial advertising electric signs, based 

on the aforementioned data and inventory estimates. 

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Table 2-21: Electric Signs Energy Consumption and Savings Estimate, 2007 

Theoretical Annual Electricity Potential Maximum Application Electricity 2007 Savings 2007 Electricity Savings Electricity Savings (TWh/yr) (TWh/yr) (TWh/yr) (TWh/yr) 

Electric Signs 11.6 0.95 6.58 7.53 

Since 2002, the annual electricity consumption of electric signs has increased from 10.0 TWh per 

to 11.6 TWh/year in 2007, due to the growth in electric sign sales. However, the growth in 

electric sign energy consumption has been tempered by the increasing penetration of LEDs in 

this application. Already, LED electric signs with an average luminaire efficacy of 49.3 lm/W14 

have reduced energy consumption in this application by 0.95 TWh/year, from 12.6 TWh/year to 

11.6 TWh/yr. This compares to negligible electricity savings from converting neon signs to LED 

electric signs in 2002. Converting all of the remaining neon signs in the 2007 baseline inventory 

to LED would save approximately 6.58 TWh/yr. In terms of primary energy consumption, 71.0 

TBtu per year could be saved based on 2007 LED penetration and if the remaining neon signs 

converted to LED sources. To put these potential energy savings into perspective, the annual 

output of one large (1000 MW) electric power plant or the annual electricity consumption of five 

hundred thousand households could be avoided if the national neon electric signage stock 

entirely shifted to LED. 

2.4.4. Technology Benefits in Addition to Energy Savings 

There are several benefits in addition to energy savings that are driving the adoption of LEDs in 

electric advertising signs. These include: 

1. Longer Operating Life 

2. Lower Maintenance and Life Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Durability 

7. Safety Improvements 

8. Color Maintenance 

9. Mercury Reduction 

10. Design Flexibility 

11. Ease of Installation and Maintenance 

For more information about these additional benefits of LEDs, refer to Table 1-2. 

14 This luminaire efficacy is an average of estimates from industry experts (Bonilla, 2008; Vincent, 2008) 

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3.	 Indoor White-Light Applications 

In addition to colored-light applications, LED sources have begun to penetrate white-light 

applications during the past few years. Improved light output and efficiencies of monochromatic 

blue LEDs have enabled the manufacture of high-brightness white LEDs, produced by 

combining a blue LED with a yellow phosphor or by mixing red, green, and blue LEDs. Warm 

white LEDs, which are more pleasing to the U.S. consumer, can be produced by using different 

different phosphors in the LED, or by combining white LEDs with monochromatic red or amber 

LEDs. LED penetration in indoor white-light applications has the potential to save substantial 

amounts of energy if LEDs can achieve the stringent color quality and color-rendering 

requirements that consumers demand in general lighting applications. As with colored-light 

applications, electricity is saved in white-light applications where LED sources are used to 

replace incandescent, halogen, and in some cases, CFL and certain types of fluorescents.. 

This report evaluates six indoor white-light niche market applications: recessed downlights, 

refrigerated display case lighting, retail display, task lighting, office undershelf lighting and 

kitchen undercabinet lighting. LED products for these indoor white-light applications are 

currently being manufactured, although the market has not yet adopted them in large numbers. 

•	 LED recessed lights have the greatest energy savings potential of all the applications 

studied in this report. 

•	 LED refrigerated display case lighting is a promising niche application because LEDs 

perform better in cold temperatures compared to room temperature, and they can provide 

more uniform lighting of the display area than the incumbent fluorescent lamp systems, 

due to the directional light output of LEDs. Wal-Mart has recently converted to LED 

refrigerated display case lighting in 500 of its U.S. stores, which may influence other 

storeowners to shift toward LEDs as well (LEDs Magazine, 2007). 

•	 LED retail display lighting is beneficial in several respects: LEDs’ small size allows them 

to be integrated unobtrusively into display cases; LED directionality allows precise 

targeting of products to be illuminated; LEDs do not damage heat or UV-sensitive 

merchandize, and, for products like jewelry and crystal, the multiple diodes of the LED 

lamp lead to more reflections and increased sparkle. 

•	 LED task lighting such as portable desk lamps, office undershelf lighting, and kitchen 

undercabinet lights have the potential to provide brighter, more directed illumination for 

work spaces than the incandescent and fluorescent products they replace. 

If LEDs become standard technology in these six indoor white-light niche market applications, 

108 TWh per year of electricity savings could be possible, equal to 1.1% of total annual primary 

energy consumption and 13% of electrical energy consumption for lighting in the U.S. in 2007. 

3.1. Recessed Downlights 

The energy savings potential of LEDs for recessed downlights is significant, more than the 

energy savings potential of any other niche application described in this report. We estimate that 

there is no market penetration of LEDs in recessed downlight applications as of 2007 because 

LED recessed downlight products only recently have become available in the market. However, 

we estimate that if all recessed downlights in the U.S. were converted to LEDs, 877 TBtu of 

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primary energy would be saved annually, the annual consumption of 12.8 large (1000 MW) 

electric power plants. This represents the annual electricity consumption of 6.7 million typical 

U.S. households. 

3.1.1. Introduction 

Although originally intended for directional lighting, recessed downlights have become the most 

common fixture used for general ambient lighting in both residential and commercial buildings. 

Recessed downlights represent 12% of all installed residential light fixtures and 15% of lighting 

energy use in the U.S. (Calwell et al., 1999). These fixtures are popular because they are 

inexpensive and can provide inconspicuous, directional or ambient light for most room types. 

For the energy consumption and savings analyses in this report, recessed downlights include 

insulated ceiling-rated, air-tight (ICAT) fixtures and non-insulated ceiling fixtures (non-IC), with 

open or enclosed reflector lamps, but not recessed troffer fixtures commonly used with linear 

fluorescent lamps. 

While some LED-based products have been offered as “substitutes” for incandescent reflector 

lamps for these applications, only in 2007 were products introduced to the market which offered 

a sufficiently bright lumen level and quality of light that they could be considered adequate 

substitutes for incandescent reflector lamps. In 2007, LED Lighting Fixtures Inc. (now Cree 

LED Lighting Solutions) won the grand prize in the Lighting for Tomorrow competition for an 

LED LR6 recessed downlight that could replace the common BR30 incandescent reflector, or 

CFL reflector lamps (Lighting for Tomorrow, 2008). 

These LED recessed downlight products, as measured by the DOE’s Commercially Available 

LED Product Evaluation and Reporting Program (CALiPER), can be more efficient in situ than 

both conventional incandescent reflector and compact fluorescent technologies (DOE, 2007b). In 

addition to being an efficient lighting technology, LED reflector lamps can also be designed for 

either directional or ambient lighting unlike reflector compact fluorescent lamps which are best 

suited for ambient lighting conditions. 

A number of sources were used to prepare the national energy consumption and potential energy 

savings estimate. As with the other niche market assessments, there are four critical inputs used 

in preparing the energy consumption and savings estimates, summarized in Table 3-1. The 

analysis considers the case of LEDs replacing incandescent or CFL recessed downlights in 

commercial or residential buildings. 

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Table 3-1: Critical Inputs for Recessed Downlights Energy Consumption and Savings Estimates 

Critical Input Notes and Sources 

Installed Base of Lamps Recessed Downlights Inventory: U.S. Census Bureau, Electric 

Light Fixture Current Industrial Reports, 1980-2001; California 

Residential Lighting and Appliance Efficiency Saturation 

Survey, RLW Analytics, 2000a, 2000b, 2005a, 2005b. 

Annual Operating Hours Distribution of Building Types: Commercial Building Energy 

Consumption Survey (CBECS), 2003; Residential Energy 

Consumption Survey (RECS), 2001. 

Operating Hours per Building Type: U.S. Lighting Market 

Characterization (LMC), Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a. 

Lamp Wattages U.S. LMC, Volume I: National Lighting Inventory and Energy 

Consumption Estimate, DOE, 2002a; NEMA Mercury Vapor 

and Parabolic Reflector (PAR/R) Lamp Survey 2003. 

LED Efficacy: CALiPER Round 3 Summary Results, DOE, 

2007c. 

Fixture Efficiencies: CALiPER Round 3 Summary Results, 

DOE, 2007c 

Lighting Technology Mix U.S. Census Bureau, Electric Light Fixture Current Industrial 

Reports, 1980-2001. California Residential Lighting and 

Appliance Efficiency Saturation Survey, RLW Analytics, 

2000a, 2000b, 2005a, 2005b. 

3.1.2. Recessed Downlights Installed Base 

We estimate that there are 829 million recessed downlight fixtures in the U.S., as shown in Table 

3-2. The commercial sector installed base of recessed downlights is derived from the Electric 

Light Fixture Current Industrial Reports published by the U.S. Census Bureau from 1980 to 

2001. This study tracks electric light fixture sales by fixture type in the U.S. for the residential, 

commercial, industrial, and outdoor stationary sectors. Recessed downlights, both ICAT and 

non-IC, open and enclosed, were among the fixtures tracked by this study. Based on the 

historical growth rate of recessed downlight shipments and an average fixture lifetime of 20 

years, an inventory of 394 million commercial recessed downlights could be estimated for 2007. 

For the residential sector, the recessed downlight inventory was estimated by using data from the 

U.S. Census Bureau’s Electric Light Fixture Current Industrial Reports and the 2000 and 2005 

California Residential Lighting and Appliance Efficiency Saturation Surveys, conducted on 

randomly selected samples of residential rate payers from four investor-owned utilities (IOUs), 

San Diego Gas and Electric, Southern California Gas Company, Southern California Edison, and 

Pacific Gas and Electric and one municipal-owned utility, the Sacramento Municipal Utility 

District (SMUD). The California household survey reports the average number of lighting 

fixtures per room for Californian residences, including the average number of recessed can 

fixtures per residence. The technology mix of recessed downlights is also provided in the 

household survey. 

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From the Census Bureau’s Electric Light Fixture Current Industrial reports, an estimate of 371 

million incandescent recessed downlight fixtures in the residential sector was calculated. 

Residential CFL recessed downlight fixtures were not tracked in the survey. The CFL recessed 

downlight inventory in the residential sector was estimated by assuming that the percentage of 

CFL recessed downlights in California (14.7%) was the same nationwide. (RLW Analytics, 

2000a, 2000b, 2005a, 2005b) This assumption yields a total of 64 million CFL recessed cans in 

the residential sector. The national residential inventory of recessed downlights, equal to the 

addition of the number of incandescent recessed downlights and compact fluorescent recessed 

downlights, is estimated to be 435 million fixtures, as shown in Table 3-2. 

At this time, well-designed LED recessed downlights are able to replace incandescent and screwbased compact fluorescent recessed downlights, which represent the majority of the 435 million 

residential recessed downlight fixtures installed in the U.S. 

Table 3-2: Installed Base of Recessed Downlight Fixtures in the U.S., 2007 

Sector Incandescent Recessed 

Downlights 

CFL Recessed 

Downlights Total 

Residential 370,765,000 64,103,000 434,868,000 

Commercial 313,548,000 80,538,000 394,086,000 

Total 684,313,000 144,641,000 828,954,000 

3.1.3. Recessed Downlights Operating Hours 

Recessed downlight fixtures in the commercial and residential sectors have different operating 

hour patterns. In the residential sector, the operating cycle of residential recessed downlights is 

approximately 2 hours per day, while in the commercial sector, the operating cycle of recessed 

downlights is approximately 9 hours per day. 

The average operating hours for recessed downlights used in various types of commercial and 

residential buildings was obtained from the U.S. Lighting Market Characterization Volume I: 

National Lighting Inventory and Energy Consumption Estimate (DOE, 2002a). The Residential 

Energy Consumption Survey (RECS) and Commercial Building Energy Consumption Survey 

(CBECS), both published by the EIA, were used to obtain the distribution of building types in 

the residential and commercial sectors. From these sources, the average operating hours in the 

residential and commercial sectors was obtained, as shown in Table 3-3. 

Table 3-3: Average Operating Hours for Recessed Downlights 

Year Residential Average Commercial Average 

Operating Hours (hrs) Operating Hours (hrs) 

2007 843 3347 

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3.1.4. Recessed Downlight Lamp Average Wattages 

For this analysis, we assume that only the reflector lamps are used in recessed downlight 

fixtures.

15 The average compact fluorescent lamp wattages for residential and commercial 

recessed downlights were estimated from the U.S. Lighting Market Characterization Volume I: 

National Lighting Inventory and Energy Consumption Estimate (DOE, 2002a). The 2003 

National Electrical Manufacturers Association (NEMA) Mercury Vapor and Parabolic Reflector 

(PAR/R) Lamp Survey for the Department of Energy (DOE) was used to determine the average 

wattage of residential and commercial incandescent reflector lamps. This study tracks the 

number of mercury vapor, incandescent, and halogen reflector lamps sold in the U.S. by wattage 

and application sector. The replacement LED wattage was determined by matching the lumen 

output for the conventional technologies and LED products, given efficacies found from 

conventional lamp catalogs (GE, OSI, Philips, 2006) and LED efficacies for the best-in-class 

products measured by DOE’s CALiPER program (DOE, 2007c). Fixture efficiencies measured 

by the CALiPER program for both LED lamps and conventional lamps in recessed cans were 

also used to determine equivalent lamp wattages (DOE, 2007c). 

Table 3-4: Average Lamp Wattage for Recessed Downlights 

Reflector 

Lamp Type 

Residential 

Average 

Wattage (W) 

Equivalent 

Residential 

LED (W) 

Commercial 

Average 

Wattage (W) 

Equivalent 

Commercial 

LED (W) 

Incandescent 72 14 72 14 

CFL 11 7 16 11 

3.1.5. Recessed Downlights Energy Saving Potential 

We assume that there is currently no market penetration of LEDs in recessed downlights, as LED 

products for this application have only recently become available in the marketplace. Table 3-5 

presents the energy consumption estimate for recessed downlights, based on the aforementioned 

data and inventory estimates. 

Table 3-5: Recessed Downlight Energy Consumption and Savings Estimate, 2007 

Application 

Annual 

Electricity 2007 

(TWh/yr) 

Electricity 

Savings 2007 

(TWh/yr) 

Potential 

Electricity Savings 

(TWh/yr) 

Theoretical 

Maximum 

Electricity Savings 

(TWh/yr) 

Recessed Downlights 103.1 0.0 81.2 81.2 

Thus, if LEDs with a luminaire efficacy of 60.9 lm/W (DOE, 2007c) achieved 100% market 

share of recessed downlights, a potential electricity savings of 81.2 TWh could be realized per 

year, the greatest electricity savings potential of any niche application described in this report. In 

terms of primary energy consumption, the potential energy savings of LED recessed downlights 

15 Due to lack of data, we assume that all recessed downlight fixtures are equipped with incandescent or CFL 

reflector lamps. However, non-reflector incandescent and CFL lamps are also used in recessed downlight fixtures. 

Because fixture efficiencies for non-reflector lamps in recessed cans are much lower than reflector lamps and 

efficacies of reflector vs. non-reflector lamps are approximately the same, energy consumption and potential energy 

savings of LEDs in this application may be understated. 

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is 877 TBtu/yr at the power plant, equivalent to the annual consumption of 12.8 large (1000 

MW) electric power plants and representing the annual electricity consumption of 6.7 million 

households. 

3.1.6. Technology Benefits in Addition to Energy Savings 

There are several benefits outside of energy savings that are driving the adoption of LED 

technology in this application. In addition to saving potentially 877 TBtu/yr of primary energy 

when the market reaches saturation, LED recessed downlights offer other advantages over 

traditional recessed downlights. These include: 

1. Longer Operating Life 

2. Lower Maintenance and Life-Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

For more information about these ancillary benefits of LEDs, refer to Table 1-2. 

3.2. Refrigerated Display Cases 

While in its nascent stage of development in the first half of this decade, LED refrigerated 

display case lighting systems did not provide any energy savings. However, during the past five 

years, technical advances in white LEDs have enabled LED refrigerated display case lighting 

systems to offer energy savings when replacing fluorescent systems in 2007. These LED 

systems have just recently entered the market, and we estimate that less than one percent of the 

market has switched to LED refrigerated display case systems, amounting to a small 0.08 TWh 

in electricity savings in 2007. 

In contrast, if 100% of the market switched to LED systems there is the potential to save 2.1 

TWh of electricity. This corresponds to a primary energy savings of 22.4 TBtu, equivalent to the 

annual consumption of one third of a (1000 MW) coal power plant or the annual electricity 

consumption of over one hundred and sixty thousand households. 

3.2.1. Introduction 

The common supermarket is the main source of produce and household goods for the majority of 

the U.S. population. Supermarkets are major energy consumers, requiring high-quality lighting 

throughout the store to illuminate merchandise and ample space heating and cooling to keep 

produce fresh and customers comfortable. Almost half of the annual electricity costs for a 

supermarket are used to operate refrigerated display cases (EPA, 2006), a term which includes 

both refrigerators and freezers. Lighting to illuminate food items contributes about 15% of the 

total electricity consumed by refrigerated display cases (DOE, 2007a). Lighting also adds to the 

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heat load of the refrigerator, leading to greater compressor energy use and greater capital costs 

required for higher-power compressors. 

The most common light source for refrigerated display cases is fluorescent lighting. Although 

fluorescent lamps are highly efficient operating at room temperature (providing 70-90 lumens 

per watt), their efficiency decreases by more than 25% when operating at refrigeration or freezer 

temperatures of 38°F to -15°F (Narendran, 2003a). In addition, because of the geometry of the 

fluorescent lamp system in a refrigerated display case and the lack of additional optics, only 

about 60% of the light generated by the fluorescent lamp is directed toward the food products on 

display. The remaining light is wasted as excess glare on the supermarket floor (Raghavan, 

2002). When one takes into account the temperature of operation and the lack of optical 

controls, the system efficiency of fluorescent lamp is approximately 38 lumens per watt 

(Narendran, 2003a). Fluorescent lamps not only degrade in efficiency in refrigerated display 

cases but they also radiate excess heat into the refrigerated space, increasing the energy 

consumed by the cooling system. 

LED systems provide a compelling alternative to fluorescent refrigerated display case lighting. 

Not only do LED systems operate efficiently at colder temperatures but light produced by the 

LED can be directed towards the displayed products. LED refrigerated display case lighting 

systems have an efficacy of 31-33 lm/W. Although, the LED systems have a slightly lower 

efficacy than the fluorescent refrigerated display case systems, the uniform lighting distribution 

of the LED system leads to similar brightness levels (measured in lux or lumens/m2) on the 

display area. Thus, LEDs using less power can be used to replace higher wattage fluorescents, 

leading to overall energy savings. 

LEDs are especially suited to refrigerated display cases for meat. The shelf life of beef is usually 

limited to 2 to 3 days due to the progressive discoloration of the beef as bacteria grow on the 

surface and oxidize the pigments in the meat. Excess heat accelerates the spoilage of meat, as 

the growth rate of bacteria increases as meat surface temperatures rise. Experiments have shown 

that lighting from general illumination and refrigerated display cases can increase meat surface 

temperatures and accelerate spoilage compared to the absence of illumination (Greer, 1984). In 

addition, surveys of retail outlets show that typical meat surface temperatures are 4 oC to 25 oC 

higher than the refrigerator temperature (Jeremiah and Gibson, 1997). LEDs are ideal for meat 

display applications because they provide similar levels of illumination while radiating less heat 

than fluorescents, which slows the growth of bacteria and increases the meat products’ shelf life. 

As this example shows, LED refrigerated display cases are a compelling product with benefits 

beyond energy savings. 

Previous studies and energy conservation standard analyses were used to update the national 

energy consumption estimate from the 2003 edition of this report. As with the other niche 

market assessments, there are four critical inputs used in preparing the energy consumption and 

savings estimates, summarized in Table 3-6. The analysis considers the case of LEDs replacing 

fluorescent refrigerated display case systems. 

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Table 3-6: Critical Inputs for Refrigerated Display Case Lighting Energy Consumption and 

Savings Potential Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Refrigerated Display Cases: Commercial 

Refrigerated Equipment Advanced Notice of Proposed 

Rulemaking National Energy Savings spreadsheets. 

Annual Operating Hours Refrigerated display cases operate continuously, amounting to 

8,760 hours/year. 

Lamp Wattages Commercial Refrigerated Equipment Notice of Proposed 

Rulemaking Engineering Analysis spreadsheets. 

Lighting Technology Mix Number of Stores with LED Cases: LEDs Magazine, 2006. 

Average Number of Case-Doors per Store: GE, 2007. 

Average Number of Doors per Case: Commercial Refrigerated 

Equipment Notice of Proposed Rulemaking Engineering 

Analysis spreadsheets. 

3.2.2. Refrigerated Display Cases Installed Base 

Industry manufactures at least 48 different refrigerated display case systems. However, the 

majority of refrigerated display cases in the market consists of four system types: vertical 

without doors, remote condensing, medium temperature (38 oF) systems [VOP.RC.M]; semivertical without doors, remote condensing, medium temperature systems [SVO.RC.M]; vertical 

with transparent doors, remote condensing, medium temperature systems [VCT.RC.M]; and 

vertical with transparent doors, remote condensing, low temperature (0 oF) systems [VCT.RC.L]. 

This analysis only considers the four main system types in the installed base calculation. 

The installed bases for the four main types of refrigerated display cases systems were obtained 

from the National Energy Savings spreadsheets from DOE’s Energy Conservation Standard 

Advanced Notice of Proposed Rulemaking on Commercial Refrigerated Equipment, and are 

shown in Table 3-7. 

Table 3-7: Installed Base of Refrigerated Display Case Lighting Systems in the U.S, 2007 

Light Percent SVO.RC.M VOP.RC.M VCT.RC.M VCT.RC.L Total Stock Source of Stock Stock Stock Stock Stock 

Fluorescent 96.4% 229,430 300,780 21,480 298,760 850,450 

LED 3.6% 8,600 11,300 850 11,250 32,000 

Total 100.0% 238,030 312,080 22,330 310,010 882,450 

With Wal-Mart’s recent installation of LED refrigerated display cases in 500 of its U.S. stores, 

we estimate that 32,000 LED refrigerated display cases are installed in the U.S. (LEDs Magazine 

2007). The total number of LED refrigerated display cases was developed by multiplying the 

number of stores with LED cases and the average number of case-doors per store, and dividing 

by the average number of doors per case. The percent LED penetration in the refrigerated 

display case market was determined by dividing the total number of LED cases by the installed 

base of refrigerated display cases in the U.S., which equals 3.6%. The remaining 96.4% of 

refrigerated display cases are assumed to be fluorescent, the standard technology in this 

application. 

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3.2.3. Refrigerated Display Cases Operating Hours 

For this analysis, refrigerated display cases lighting systems for both conventional and LED 

systems are assumed to operate 24 hours per day year-round, amounting to an annual operating 

cycle of 8,760 hours. However, it should be noted that additional energy savings can be 

achieved through the use LED refrigerated display cases with lighting controls. LEDs can be 

dimmed more efficiently than fluorescents because rapid and frequent on/off cycles do not affect 

the life of the LED, enabling the use of movement-triggered controls. These controls can reduce 

the annual operating hours of the LED system and lead to even greater energy savings calculated 

in this report. 

3.2.4. Refrigerated Display Cases Lamp and Ballast/Driver Average Wattages 

The average lamp and ballast or driver wattages were determined from the Engineering Analysis 

spreadsheets for the DOE’s Energy Conservation Standard Notice of Proposed Rulemaking for 

Commercial Refrigerated Equipment. The lighting system wattages for each of the four main 

types of systems were weighted by the 2007 installed base of each of those refrigerated display 

case lighting systems to obtain the total average wattage for fluorescent and LED refrigerated 

display case lighting systems. Each 16-watt LED strip was modeled to replace a single fourfoot, 76 CRI, 85 lm/W, nominally 32-watt, T8 lamp powered by a standard two-lamp electronic 

ballast. 

Table 3-8: Average System Wattages for Refrigerated Display Case Lighting Systems 

Light Source 

SVO.RC.M VOP.RC.M VCT.RC.M VCT.RC.L Total Average 

Wattage Average Average Average Average 

Wattage Wattage Wattage Wattage 

Fluorescent 458 642 348 348 482 

LED 244 342 224 224 271 

3.2.5. Refrigerated Display Cases Energy Saving Potential 

The annual electricity consumption of the over ten million refrigerated display cases in the U.S. 

was 3.7 TWh per year of lighting electricity use and 9.7 TWh per year of compressor electricity 

use for a total of 13.5 TWh/yr with the potential for reduction through the use of LEDs with an 

average luminaire efficacy of 30.4 lm/W. Almost four percent of the national installed base of 

refrigerated display case lighting systems consists of LEDs, saving 0.08 TWh/yr of electricity in 

2007 through reductions in lighting (0.06 TWh/yr) and compressor (0.02 TWh/yr) electricity use. 

However, the potential to save an additional 2.0 TWh/yr of electricity exists if the commercial 

refrigerated display case market completely switched to LED systems, through reductions of 1.6 

TWh/yr of lighting electricity use and 0.4 TWh/yr of compressor electricity use. This 

corresponds to 21.6 TBtu/yr of primary energy savings at the power plant, the energy 

consumption of one third of a 1000 MW coal power plant or equivalent electricity consumption 

of one hundred and sixty thousand households. 

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Table 3-9: Refrigerated Display Case Lighting and Compressor Energy Consumption and 

Savings Estimate, 2007 

Niche Application 

Annual 

Electricity 

Consumption 

2007 (TWh) 

Electricity 

Savings 2007 

(TWh) 

Potential 

Electricity 

Savings (TWh) 

Theoretical 

Maximum 

Electricity 

Savings (TWh) 

Refrigerated Display Cases 13.4 0.08 2.00 2.1 

3.2.6. Technology Benefits in Addition to Energy Savings 

White LED lamps offer several advantages that will make them suitable to this niche application. 

LED light sources for commercial refrigerated display cases offer several benefits and features to 

storeowners that set them apart from fluorescent. These features can help improve the marketing 

and enhance the sales of products displayed. These benefits include: 

1. Longer operating life 

2. Lower Maintenance and Life Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

7. Durability 

8. Smaller Package Size 

9. Uniform Illumination 

10. Adjustable Color 

11. Increased product shelf life 

These features, both financial and aesthetic, make LED light sources a compelling alternative to 

fluorescent. For more information about individual ancillary benefits, refer to Table 1-2. 

3.3. Retail Display 

LED retail display products have recently been introduced on the market and have reached 

efficiencies high enough to displace incandescent, halogen, CFL and certain types of fluorescent 

spot-, flood-, and track-lights used to display merchandise in retail stores. LED retail display 

lights have the potential to save 7.87 TWh/yr if 100% of the market shifted to LEDs, equal to 

84.9 TBtu/ yr of primary energy consumption. This amounts to the annual consumption of one 

large (1000 MW) electric power plant or the annual electricity consumption of seven hundred 

thousand U.S. households. We estimate that there is no penetration of LEDs in retail display 

applications as of 2007 because products have only recently entered the market. 

3.3.1. Introduction 

Shopping centers rely on bright, high-quality lighting to highlight merchandise and attract 

customers into stores. Lighting can help indicate to customers the quality of products inside, the 

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price point, and the type of service they can expect (Lane, 2007). Window displays and display 

cases require high brightness levels to distinguish products from the background. Empirical 

research on consumer behavior in retail environments shows that consumers are more likely to 

examine and handle merchandise under bright lighting than under soft lighting (Summers, et. al 

2001). As a result, lighting is the biggest energy-related expense for retailers at 37% of annual 

energy expenditures, not including the added space cooling costs associated with the heat loads 

from lighting (DOE, 2006b). Energy-efficient lighting can boost the bottom line for retailers, 

since “saving $1 in energy costs can improve profits as much as increasing sales by $80” 

(Vrabel, 2003). 

Several types of lighting systems can be found in a typical retail environment such as ambient 

lighting, task lighting, perimeter lighting, and display case lighting. Retail display lighting is of 

particular interest for energy efficiency measures because they are high-power, high-brightness 

fixtures. These lighting systems typically supply 30 to 100 footcandles (fc) on merchandise and 

150 to 500 fc on feature displays to provide contrast between highlighted merchandise and the 

surrounding area, which is typically lit at a lower 10 to 30 fc brightness level (Lane, 2007). 

Retail display lighting includes three main types of systems: (1) accent lighting is accomplished 

using track-, spot-, or flood-light luminaires to draw customer attention to specific merchandise 

and should be illuminated at least three times brighter than the surroundings to be noticeable and 

five times brighter to be meaningful, according to IESNA recommendations (Vrabel, 2003; 

IESNA, 2001); (2) focal-point lighting should be ten times brighter than the surroundings, and 

usually uses spotlights to highlight specific central displays of merchandise; and (3) display case 

lighting illuminates merchandise in glass or open shelves or cases, and uses linear fluorescent or 

spot lighting (Vrabel, 2003). 

The most common light source for retail display lighting is linear fluorescent track lighting to 

provide accent or display case lighting, followed by halogen or incandescent spot lights to 

provide high-brightness focal-point lighting. Carefully designed LED systems can be viable 

alternatives to all three of these conventional lighting systems. One strategy is to replace high 

power white incandescent or halogen spotlights with colored LEDs for feature displays to draw 

the customer’s attention. Controlled experiments in retail stores have shown an increase in 

positive consumer emotions and greater handling of products lighted under colored LED lighting 

(Freyssinier, et al., 2006; Summers, et. al, 2001; Tullman, 2000). Another strategy is to replace 

high wattage incandescent, halogen and even CFL reflector lamps with LED reflector lamps. As 

discussed previously, LED reflector lamps, unlike CFL reflector lamps can be serve for both 

directional and ambient lighting applications. Efficient linear LED fixtures are also available to 

replace magnetic T12 linear fluorescent track lighting systems less than 4-feet in length and 

magnetic U-bent T12 fluorescent systems with low fixture efficiencies. Since LED retail display 

products have only recently entered the market, we assume that there is no LED penetration in 

this application as of 2007. 

One retail display application especially suited to LED lighting is jewelry display cases. Light 

from each LED in the jewelry case lighting system is reflected by the gem’s facets leading to 

more reflections and greater perceived sparkle than gems lit by a single incandescent, halogen, or 

fluorescent lamp with equal lumen output. Increased sparkle makes LED-lit jewelry appear to be 

of higher quality and enhances sales according to an industry case study (Costco, 2007). LED 

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jewelry cases can also be designed to conceal the lighting system as much as possible for clear 

display of merchandise. 

Previous studies and researchers were consulted to create the national energy consumption and 

savings estimates for retail display lighting. As with the other niche market assessments, there 

are four critical inputs used in preparing the energy consumption and savings estimates, 

summarized in Table 3-10. The analysis considers the case of LEDs replacing incandescent, 

halogen, CFL, and T12 fluorescents less than 4-feet in length, or U-bent T12 fluorescent retail 

display lighting systems. 

Table 3-10: Critical Inputs for Retail Display Lighting Energy Consumption and Savings
 

Potential Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Retail Display Lighting Systems per Square Foot: U.S. 

Lighting Market Characterization, Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a. 

Commercial Floorspace Growth Rate: EIA’s Commercial Building 

Energy Consumption Survey (CBECS), 2003, 1999. 

Annual Operating Hours U.S. Lighting Market Characterization, Volume I: National 

Lighting Inventory and Energy Consumption Estimate, DOE, 

2002a. 

Lamp Wattages Conventional Product Lamp Wattages: U.S. Lighting Market 

Characterization, Volume I: National Lighting Inventory and 

Energy Consumption Estimate, DOE, 2002a.; NEMA Mercury 

Vapor and Parabolic Reflector (PAR/R) Lamp Survey 2003; 

NEMA A-line Statistical Wattage Survey 2005. 

Conventional Product Fixture Efficiencies: CALiPER 5: Summary 

Results, DOE, 2008b, Mia Paget, Pacific Northwest National 

Laboratory, 2008. 

LED Product Efficacies: CALiPER 5: Summary Results, DOE, 

2008b, CALiPER 3: Summary Results, DOE, 2007c. 

Lighting Technology Mix Conventional Technology Mix: U.S. Lighting Market 

Characterization, Volume I: National Lighting Inventory and 

Energy Consumption Estimate, DOE, 2002a. 

3.3.2. Retail Display Installed Base 

We estimate that there are approximately 171 million retail display lighting fixtures in the U.S., 

as shown in Table 3-11. The installed base of retail display lights is derived from commercial 

building survey from the U.S. Lighting Market Characterization Volume I: National Lighting 

Inventory and Energy Consumption Estimate (DOE, 2002a), which provides data on display 

lighting fixtures per square foot of retail (open, enclosed, and strip-mall) floorspace. This survey 

also provides the technology mix of display lighting fixtures in 2001. Assuming a 1.6% annual 

commercial floorspace growth rate (EIA, 2003, 1999), we calculate the inventory of retail 

display lighting fixtures in 2007. We assume the technology mix of display lighting fixtures has 

not changed substantially between 2001 and 2007. 

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Table 3-11: Installed Base of Retail Display Fixtures in the U.S., 2007 

Light Source 

Technology mix Number of 

Installations of Retail Display 

lights (%) 

Standard - General Service 2.2% 3,829,000 

Standard – Reflector 5.5% 9,454,000 

Halogen – Quartz 2.4% 4,063,000 

Halogen - refl. - low volt 8.3% 14,223,000 

T8 – less than 4’ 2.2% 3,767,000 

T8 – 4’ 50.1% 85,678,000 

T8 – U-bent 2.8% 4,738,000 

T12 – less than 4’ 0.8% 1,387,000 

T12 – 4’ 15.8% 27,095,000 

T12 – More than 4’ 7.9% 13,505,000 

T12 – U-bent 1.0% 1,757,000 

Compact – Screw base 0.9% 1,498,000 

Total 100.0% 170,994,000 

3.3.3. Retail Display Operating Hours 

The average operating hours for retail display lighting was estimated from the U.S. Lighting 

Market Characterization Volume I: National Lighting Inventory and Energy Consumption 

Estimate (DOE, 2002a). Retail buildings such as open stores, enclosed shopping malls, and strip 

malls provided data on display lamp operation in the commercial building survey. Assuming 

that hours of operation have not changed between 2001 and 2007, retail display lights are on 

throughout the open hours of the store, for an average of 3937 hours per year or 10.8 hours per 

day. 

3.3.4. Retail Display System Average Wattages 

Table 3-12 shows the average retail display lighting system wattage obtained from the lamp 

wattages published in the commercial building survey of the U.S. Lighting Market 

Characterization Volume I: National Lighting Inventory and Energy Consumption Estimate 

(DOE, 2002a). Using average ballast factors for fluorescent lamps and published average fixture 

efficiencies (DesignLights, 2003), system wattages for the retail display systems could be 

calculated. LED replacements for the retail display products were determined by matching the 

lumen output of the LEDs and conventional products, assuming an average LED retail display 

lighting efficacy from best-in-class products measured by the CALiPER testing program (DOE, 

2008b,2007c) and conventional product efficacies from manufacturer datasheets and published 

reports (GE, 2006; DOE, 2002a). Since LED retail display products are less efficient than all 

types of T8 fixtures and 4-foot and greater length T12 fixtures, LEDs are only modeled to 

replace incandescent, halogen, T12s less than 4-foot in length, U-bent T12s, and compact 

fluorescent fixtures, representing 21% or 36.2 million fixtures of total retail display fixtures. 

42 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 3-12: Conventional and LED Retail Display System Wattage 

Light Source Retail Display 

System Power (W) 

LED 

Replacement (W) 

General Service – Incandescent 67 9 

Incandescent – Reflector 72 13 

Halogen – Quartz 226 69 

Halogen - refl. – low volt 48 8 

T12 – less than 4’ 31 29 

T12 – U-bent 49 46 

Compact – Screw base 16 11 

3.3.5. Retail Display Energy Saving Potential 

The approximately 171 million retail display lighting systems in the U.S. consumed 32.0 TWh/yr 

of electricity, excluding the heating loads from the lighting systems, as shown in Table 3-13. 

There were no energy savings from LED retail display lighting systems as LED products have 

only recently become available on the market. However, the retail display lighting market has 

the potential to save 7.87 TWh/yr of electricity if the 36.2 million retail display fixtures 

containing incandescents, halogens, T12s less than 4-feet in length, U-bent T12s, and CFLs 

switched to LED systems with an average luminaire efficacy of 46.5 lm/W (DOE 2008b, 2007c). 

This corresponds to 84.9 TBtu per year of primary energy savings at the power plant, the energy 

consumption of one 1000 MW coal power plant or the equivalent electricity consumption of 

seven hundred thousand households. 

Table 3-13: Retail Display Case Energy Consumption and Savings Estimate, 2007 

Niche Application 

Annual Electricity 

Consumption 

2007 (TWh) 

Electricity 

Savings 2007 

(TWh) 

Potential 

Electricity 

Savings (TWh) 

Theoretical 

Maximum 

Electricity Savings 

(TWh) 

Retail Display Lighting 32.0 0.0 7.87 7.87 

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3.3.6. Technology Benefits in Addition to Energy Savings 

White and colored LED lamps offer several advantages that will make them suitable to this niche 

application. LED light sources for retail display lighting offer several benefits and features to 

storeowners that set them apart from incandescent, halogen, and fluorescent products. These 

features can help improve marketing efforts and enhance the sales of products displayed. These 

features, both financial and aesthetic, make LED light sources a compelling alternative to 

fluorescent, as described in Table 1-2. These benefits include: 

1. Longer operating life 

2. Lower Maintenance and Life Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

7. Smaller Package Size 

8. Uniform Illumination 

9. Adjustable Color 

10. Enhanced product appearance
 

.
 

3.4. Task Lighting 

In the last five years, LED task lighting products have been introduced on the market as 

replacements to inefficient incandescent, halogen, and T12 and circline fluorescent task lights 

used in the commercial, industrial, and residential sectors. LED task lights have the potential to 

save 13.0 TWh/yr if the entire market shifted to 2007 LED technology, equal to 140.1 TBtu/yr of 

primary energy consumption. This amounts to the annual consumption of two large (1000 MW) 

coal power plants or the annual electricity consumption of one million U.S. households. We 

estimate that there is no penetration of LEDs in task lighting applications as of 2007 because 

products have only recently entered the market. 

3.4.1. Introduction 

Task lighting is used to increase illumination on work surfaces above ambient levels. Two 

specific types of task lights, office undershelf and kitchen undercabinet fixtures, are described in 

sections 3.5 and 3.6; this section focuses on the energy consumption and savings of other 

(usually portable) task lights such as desk, table, or reading lamps. Studies have shown that 

when task lights provide brightness levels necessary to perform work tasks, as much as 33% 

energy savings can be achieved by lowering overhead lighting (Waste Reduction Partners, 2004; 

LBL, 1997). The IESNA has established standards for how much illumination is required for 

performing various tasks, ranging from “Category D”, 10 to 50 footcandles (lumens per square 

foot), for typical office tasks such as reading computer screens or typed original documents on 

white paper to “Category E”, 50 to 100 fc, for reading books or handwritten notes 

(ANSI/IESNA, 2004). 

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Task lights are used in all sectors of the economy, from commercial offices and industrial 

facilities to residential households. The most common task light technologies in use depend on 

the sector; commercial and industrial settings rely heavily on T8 and T12 systems while the 

residential stock of task lights are mostly incandescent. The efficiencies of these systems vary 

widely based on luminaire design. Optimal luminaire design maximizes fixture efficiency while 

limiting direct (bare bulb), reflected (from a shiny surface) or veiling (contrast-limiting) glare 

(Wolsey and Miller, 1994). 

Task lights are especially important for applications where most occupants are over 55 years old, 

such as retirement homes. Starting around age 45, the eye’s capacity to focus at close range 

progressively decreases and stabilizes around ages 60 to 65. The eye’s crystalline lens capsule 

begins to harden and thicken, absorbing more light so that less light reaches the retina. This 

effect is intensified as the pupil becomes smaller in size with increasing age. At the same light 

level, a typical 60-year old receives about one-third the retinal illuminance of a 20-year old 

(Figueiro, 2001). As a result, the typical 60- to 65-year old requires 2.5 times more light than a 

20- to 25-year old to achieve the same level of visual acuity for tasks such as reading (Tetlow, 

2007). Through adjustable task lights, offices and residences can provide light levels necessary 

for all age levels. 

LED task lights are starting to appear in the market. These task lights are able to take advantage 

of both the directional light output and high efficacies of LEDs. DOE’s CALiPER program has 

tested the luminaire efficacies of several LED desk lamps (DOE, 2008a). These LED task lights 

can be more efficient than incandescent, halogen, and even some fluorescent fixtures. Since 

LED task lights have only recently become available in the market, we estimate that there is no 

significant market penetration of LEDs in this application. 

Previous studies, researchers, and results from DOE’s CALiPER program were consulted to 

create the national energy consumption and savings estimates for task lighting. As with the other 

niche market assessments, there are four critical inputs used in preparing the energy consumption 

and savings estimates, summarized in Table 3-14. The analysis considers the case of LEDs 

replacing incandescent, halogen, T12 and circline fluorescent task lighting systems, which 

represent about 96% of the total task light inventory, as described in the next section. 

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Table 3-14: Critical Inputs for Task Lighting Energy Consumption and Savings Potential
 

Estimate
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Commercial and Industrial Task Lights: U.S. 

Lighting Market Characterization, Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a. 

Number of Residential Task Lights: California Residential 

Lighting and Appliance Efficiency Saturation Survey, RLW 

Analytics, 2000, 2005; Residential Lighting: The Data to Date, 

Jennings, et. al., 1996. 

Commercial Floorspace Growth Rate: EIA’s Commercial 

Building Energy Consumption Survey (CBECS), 2003, 1999. 

Industrial Floorspace Growth Rate: EIA’s Manufacturing 

Energy Consumption Survey (MECS), 1998, 1994. 

Annual Operating Hours U.S. Lighting Market Characterization, Volume I: National 

Lighting Inventory and Energy Consumption Estimate, DOE, 

2002a. 

Lamp Wattages Conventional Product Lamp Wattages: U.S. Lighting Market 

Characterization, Volume I: National Lighting Inventory and 

Energy Consumption Estimate, DOE, 2002a.; NEMA Mercury 

Vapor and Parabolic Reflector (PAR/R) Lamp Survey 2003; 

NEMA A-line Statistical Wattage Survey 2005. 

Conventional Product Fixture Efficiencies: Mia Paget, PNL, 

2008. 

LED Product Efficacies: CALiPER Round 3 and 4 Summary 

Results, DOE, 2007c, 2008c. 

Lighting Technology Mix Commercial and Industrial Technology Mix: U.S. Lighting 

Market Characterization, Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a. 

Residential Technology Mix: California Residential Lighting 

and Appliance Efficiency Saturation Survey, RLW Analytics, 

2000, 2005. 

3.4.2. Task Lighting Installed Base 

We estimate that there are 432 million task lighting fixtures in the U.S., as shown in Table 3-15. 

The installed base of task lights is derived from a variety of sources for the commercial, 

industrial, and residential sectors. The inventory of commercial and industrial task lights were 

estimated from the U.S. Lighting Market Characterization Volume I: National Lighting 

Inventory and Energy Consumption Estimate (DOE, 2002a), which provides data on task lighting 

fixtures per square foot of commercial and industrial floorspace. This survey also provides the 

technology mix of task lighting fixtures in 2001. Assuming a 1.6% annual commercial 

floorspace growth rate (EIA, 2003, 1999) and 1.0% annual industrial floorspace growth rate 

(MECS), we calculated the inventory of commercial and industrial task lighting fixtures in 2007. 

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We assume the technology mix of task lighting fixtures has not changed substantially between 

2001 and 2007. 

For the residential sector, we estimated the task light inventory from the 2000 and 2005 

California Residential Lighting and Appliance Efficiency Saturation Surveys, conducted on 

randomly selected samples of residential rate payers from four investor-owned utilities (IOUs) 

and one municipal-owned utility. The survey reports on the average number of lighting fixtures 

per room for California residences, including the average number of table lamps per residence.16 

Assuming that the prevalence of task lights is equally likely in California and nationwide, we 

were able to develop an inventory by multiplying the average number of task lights per 

California household by the number of U.S. households in 2007 (U.S. Census Bureau, 2007). 

The technology mix of task lights were also provided in the survey. At this time, LED task 

lamps are able to replace incandescent, halogen, T12 and circline fluorescent task lighting 

systems, which represent about 97% of the total task light inventory, or 420 million task lighting 

systems. 

Table 3-15: Task Lighting Installed Base and Technology Mix, 2007 

Light Source 

Commercial 

Technology mix of 

task lights(%) 

Industrial 

Technology mix 

of task lights(%) 

Residential 

Technology mix of 

task lights(%) 

Number of 

Installations 

General Service Incandescent 28.9% 2.24% 74.7% 308,784,000 

Incandescent Reflector 22.7% 4.35% 0.00% 5,258,000 

General Service Halogen 0.00% 0.00% 4.71% 19,044,000 

Halogen – Quartz 5.03% 0.79% 0.00% 1,159,000 

T8 – less than 4’ 34.7% 39.2% 0.00% 9,529,000 

T12 – less than 4’ 1.98% 0.63% 0.00% 471,000 

T12 – 4’ 0.00% 11.5% 0.00% 521,000 

T12 – More than 4’ 0.00% 32.7% 0.00% 1,485,000 

Circline 0.35% 8.22% 0.00% 453,000 

Compact – Screw base 6.35% 0.44% 20.6% 84,799,000 

Total 100.0% 100.0% 100.0% 431,503,000 

3.4.3. Task Lighting Operating Hours 

The average operating hours for task lighting was estimated from the U.S. Lighting Market 

Characterization Volume I: National Lighting Inventory and Energy Consumption Estimate 

(DOE, 2002a) for the residential, commercial, and industrial sectors. Assuming that hours of 

operation have not changed between 2001 and 2007, annual operating hours by sector are shown 

in Table 3-16. 

16 The only lighting fixtures tracked in the California household survey that resembles a portable task light is a table 

lamp. Because we assume that all of these table lamps serve a task light function versus an ambient lighting 

function, we may be overestimating the energy consumption and savings potential due to LEDs in this application. 

47 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 3-16: Task Lighting Annual Operating Hours by Lamp Type 

Light Source Commercial Task Industrial Task Residential Task 

Lights (Hrs) Lights (Hrs) Lights (Hrs) 

Sector Average Annual 

Operating Hours 3,509 3,150 623 

3.4.4. Task Lighting Lamp Average Wattages 

Table 3-17 and Table 3-18 show the average task lighting system wattage obtained from the 

lamp wattages published in the commercial and industrial buildings survey of the U.S. Lighting 

Market Characterization Volume I: National Lighting Inventory and Energy Consumption 

Estimate (DOE, 2002a). Table 3-19 shows residential task lighting system wattages which were 

determined using the 2000 and 2005 California Residential Lighting and Appliance Efficiency 

Saturation Surveys. Using average ballast factors and efficiencies for fluorescent lamps and an 

average fixture efficiency of 50% for task lighting (Paget, 2008), system wattages for the task 

lighting systems could be calculated. LED replacements for the task lighting products were 

determined by matching the lumen output of the LEDs and conventional products, assuming an 

LED task light luminaire efficacy of 38.3 lm/W from the best-in-class product measured by the 

CALiPER program (DOE, 2008c, 2007c). Since LED task lights are less efficient than products 

with T8 fluorescents less than or equal to 4-feet in length and T12 fluorescents greater than 4-

feet in length, these products are not included in the energy savings calculations. 

Table 3-17: Commercial Conventional and LED Task Light System Wattages 

Light Source Commercial Task Light Commercial LED 

System Power (W) Replacement (W) 

General Service Incandescent 83 15 

Incandescent – Reflector 72 11 

Halogen – Quartz 78 15 

T12 – less than 4’ 31 25 

Circline Fluorescent 33 16 

Compact – Screw base 16 11 

Table 3-18: Industrial Conventional and LED Task Light System Wattages 

Light Source Industrial Task Light Industrial LED 

System Power (W) Replacement (W) 

Incandescent – Reflector 102 18 

Halogen – Quartz 452 124 

T12 – less than 4’ 34 28 

T12 – 4’ 47 40 

Circline Fluorescent 39 20 

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Table 3-19: Residential Conventional and LED Task Light System Wattages 

Light Source Residential Task Light Residential LED 

System Power (W) Replacement (W) 

General Service Incandescent 67 12 

Halogen – General Service 72 13 

Circline Fluorescent 11 8 

3.4.5. Task Lighting Energy Saving Potential 

The 432 million task lighting systems in the U.S. consumed 18.8 TWh/yr of electricity 

(excluding the heating loads from the lighting systems), as shown in Table 3-20. There were no 

energy savings from LED task lighting systems in 2007 as LED products have only recently 

become available on the market. However, if LED task lights with an average luminaire efficacy 

of 38.3 lm/W (DOE, 2008c, 2007c) replaced the 420 million task lights with incandescent, 

halogen, T12s ≤ 4-feet in length, and circline fluorescent lamps the task lighting market has the 

potential to save 13.0 TWh/yr of electricity. This corresponds to 140.1 TBtu per year of primary 

energy savings at the power plant, the energy consumption of two 1000 MW coal power plants 

or equivalent electricity consumption of one million households. 

Table 3-20: Task Lights Energy Consumption and Savings Estimate, 2007 

Niche Application 

Annual Electricity Electricity Potential Theoretical 

Consumption Savings 2007 Electricity Maximum Electricity 

2007 (TWh) (TWh) Savings (TWh) Savings (TWh) 

Task Lights 18.8 0.0 13.0 13.0 

3.4.6. Technology Benefits in Addition to Energy Savings 

White LED lamps offer several advantages that will make them suitable to this niche application, 

as described in Table 1-2. LED light sources for task lighting offer several benefits and features 

to residential, commercial, and industrial users that set them apart from incandescent, halogen, 

and some fluorescent products. These benefits include: 

1. Longer Operating Life 

2. Lower Maintenance and Life-Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

7. Smaller Package Size 

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3.5. Office Undershelf Lighting 

A type of task lighting, LED office undershelf lighting systems have been introduced on the 

market as replacements for T12 and T8 fluorescent products used in the commercial offices. 

LED office undershelf lights have the potential to save 1.37 TWh/yr if the entire market shifted 

to 2007 LED technology, equal to 14.8 TBtu/yr of primary energy consumption. This amounts 

to about 20% of the annual consumption of one large (1000 MW) electric power plant or the 

annual electricity consumption of one hundred thousand U.S. households. We estimate that there 

is no penetration of LEDs in office undershelf lighting in 2007 because products have only 

recently entered the market. 

3.5.1. Introduction 

Office undershelf lighting is the main type of task lighting in commercial offices. 

Approximately one-third of office workers in the U.S. use partitioned workstations, which 

commonly include undershelf task lights. These task lights account for about 90 percent of all 

office task lighting sold (Wolsey and Miller, 1994). Task lighting can minimize the ambient 

light needed in offices, leading to overall electricity savings. Task lighting, as described in 

Section 3.4, is important to achieve IESNA-recommended lighting levels for reading and other 

tasks and minimize eye strain (ANSI/IESNA, 2004). 

Office undershelf lighting should be designed to minimize glare and reflections off the work 

surface that cause visual discomfort. The efficacy of an office undershelf lighting product 

depends heavily on fixture efficiency and the distribution of light over the desk. Luminaire 

efficacies for undershelf lighting depend on the light output on the desk plane instead of total 

light output from the luminaire. This definition excludes light that illuminates areas other than 

the work space (LRC-ASSIST, 2007). 

Fluorescent lamps, T8s and T12s, are most commonly used for office undershelf lighting. 

However, fixture efficiencies are typically less than 40% for these fluorescent undershelf lighting 

systems (DOE, 2008e). Because of the directional quality of LEDs, more lumens are directed on 

the work space, and fewer wasted lumens are directed upward or on the back of the shelf. 

A number of sources were used to prepare a national estimate of the energy consumption and 

savings of office undershelf lighting products. As with the other niche market assessments, there 

were four critical inputs used in preparing the energy consumption and savings estimates, 

summarized in Table 3-21. 

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Table 3-21: Critical Inputs for Office Undershelf Lighting Energy Consumption and Savings
 

Potential Estimate
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Office Undershelf Lighting Systems: U.S. Census 

Bureau, Electric Light Fixture Current Industrial Reports, 1991-

2001. 

Annual Operating Hours Analysis of Standard Options for Under Cabinet Fluorescent 

Fixtures Attached to Office Furniture, Energy Solutions, 2004. 

Lamp Wattages Conventional Product Lamp Wattages: Analysis of Standard 

Options for Under Cabinet Fluorescent Fixtures Attached to 

Office Furniture, Energy Solutions, 2004. 

LED Product Efficacies: CALiPER 3 Summary Report, DOE, 

2007c. 

Fixture Efficiency: Undercabinet factsheet, DOE, 2008e. 

Lighting Technology Mix Conventional Technology Mix: Energy Solutions, Analysis of 

Standard Options for Under Cabinet Fluorescent Fixtures 

Attached to Office Furniture, 2004; NEMA, Special Statistical 

Bulletin for the Lamps Section, 2006. 

3.5.2. Office Undershelf Lighting Installed Base 

We estimate that there are 53 million office undershelf lighting fixtures in the U.S., as shown in 

Table 3-22. Assuming an average fixture lifetime of 20 years, we calculated the national 

inventory of office undershelf lighting systems from annual shipments of undershelf electric light 

fixtures collected by the U.S. Census Bureau from 1991 to 2001. The technology mix of T12 

versus T8 fluorescent lamps for undershelf lighting systems was determined from the 2006 

National Electrical Manufacturers Association (NEMA)’s Special Statistical Bulletin for Lamps. 

Table 3-22: Office Undershelf Installed Base, 2007 

Light Source Market Share (%) Installed Base 

T12 Fluorescent, Magnetic Ballast 44.7% 23,663,000 

T8 Fluorescent, Electronic Ballast 55.3% 29,297,000 

Total 100.0% 52,950,000 

3.5.3. Office Undershelf Lighting Operating Hours 

Office undershelf lighting systems operate for an average of 2000 hours per year, amounting to 

about 5.5 hours per day or 8 hours per work day. This estimate is from the Analysis of Standard 

Options for Under Cabinet Fluorescent Fixtures Attached to Office Furniture (Energy Solutions, 

2004), a report that estimates the energy savings of more stringent energy efficiency standards 

for fluorescent office undershelf lamps and ballasts in California. We assume that hours of 

operation have not changed during 2001 to 2007. 

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3.5.4. Office Undershelf Lighting System Average Wattages 

Table 3-23 shows the average office undershelf lighting system wattage obtained from the lamp 

wattages published in Analysis of Standard Options for Under Cabinet Fluorescent Fixtures 

Attached to Office Furniture (Energy Solutions, 2004). Using average ballast factors and 

efficiencies for fluorescent lamps, system wattages for the office undershelf lighting systems 

could be calculated. LED replacements for the office undershelf lighting products were 

determined by matching the lumen output of the LEDs and conventional products, assuming an 

average LED undershelf lighting system efficacy from the best-in-class products measured by 

the CALiPER program (DOE, 2007c) and including measured undershelf fixture efficiencies for 

LED and conventional products (DOE, 2008e). 

Table 3-23: Office Undershelf System Average Wattage and LED Equivalent 

Light Source System Watts (W) LED Equivalent (W) 

T12 Fluorescent, Magnetic Ballast 36 19 

T8 Fluorescent, Electronic Ballast 29 20 

3.5.5. Office Undershelf Lighting Energy Saving Potential 

The 53 million office undershelf lighting systems in the U.S. consumed 3.43 TWh/yr of 

electricity, as shown in Table 3-24. There were no energy savings from LED office undershelf 

lighting systems in 2007 as LED products have only recently become available on the market. 

However, the office undershelf lighting market has the potential to save 1.37 TWh/yr of 

electricity if the market completely shifted to LED systems with an average efficacy of 45.5 

lm/W (DOE, 2007c). This corresponds to 14.8 TBtu per year of primary energy savings at the 

power plant, equal to 20% of the annual output of one 1000 MW coal power plant or the 

equivalent annual electricity consumption of one hundred thousand households. 

Table 3-24: Office Undershelf Energy Consumption and Savings Potential, 2007 

Niche Application 

Annual Electricity 

Consumption 2007 

(TWh) 

Electricity 

Savings 

2007 (TWh) 

Potential 

Electricity 

Savings (TWh) 

Theoretical 

Maximum Electricity 

Savings (TWh) 

Office Undershelf 

Lighting 3.43 0.0 1.37 1.88 

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3.5.6. Technology Benefits in Addition to Energy Savings 

White LED lamps offer several advantages that will make them suitable to this niche application. 

LED light sources for office undershelf lighting offer several benefits and features to office 

workers that set them apart from fluorescent products. These benefits, as described in Table 1-2, 

include: 

1. Longer Operating Life 

2. Lower Maintenance and Life Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

3.6. Kitchen Undercabinet Lighting 

A similar promising niche application for LEDs is kitchen undercabinet lighting, a form of 

residential task lighting. LED kitchen undercabinet lighting systems have been introduced on the 

market as replacements to incandescent, halogen, T12 and T8 fluorescent products used in U.S. 

kitchens. LED kitchen undercabinet lights have the potential to save 2.22 TWh/yr if the entire 

market shifted to 2007 LED technology, equal to 24.0 TBtu/yr of primary energy consumption. 

This amounts to the 35% of the annual output of one large (1000 MW) coal power plant or 

annual electricity consumption of almost two hundred thousand U.S. households. We estimate 

that there is no penetration of LEDs in kitchen undercabinet lighting as of 2007 because products 

have only recently entered the market and widespread adoption has yet to occur. 

3.6.1. Introduction 

Kitchens require high-quality lighting to illuminate various surfaces of differing heights and 

materials. Counters are often made of shiny or dark materials that require glare control or highbrightness fixtures. Much of the counter area is severely shadowed even though this is where the 

majority of food preparation is conducted. Kitchen lighting designs should have high CRI (color 

rendering index) because color is a main indicator of food freshness. Optimal designs avoid 

glare and excess heat, which accelerates food spoilage and is uncomfortable to the kitchen 

occupant. An increasingly popular task lighting fixture in kitchens is the undercabinet light, 

which illuminates the counters during food preparation and cooking. We estimate that 26.1% of 

kitchens in the U.S. use undercabinet lighting products. This number is growing as they are 

becoming more common in new houses and lighting retrofit projects (RLW Analytics, 2000, 

2005). 

Fluorescent lamps, T12s and T8, are commonly used for kitchen undercabinet lighting. 

Incandescent or halogen bi-pin lamps, puck lights, wedge lamps, festoons and light strips are 

also popular. LEDs are good substitutes because of the low efficacies of incandescent and 

halogen lamps and the low fixture efficiencies (less than 40%) of fluorescent undercabinet 

lighting systems due to the geometry of the fluorescent lamp (DOE, 2008e). The directional 

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quality of LEDs leads to more lumens on the countertop, and fewer wasted lumens trapped 

within fixture or directed away from the work plane. Warm-white LEDs with high CRI are 

preferred to render the food as attractively and realistically as possible. 

A number of sources, including previous studies and databases, were consulted to prepare a 

national estimate of the energy consumption and savings of kitchen undercabinet lighting 

systems. As with the other niche market assessments, there were four critical inputs used in 

preparing the energy consumption and savings estimates, summarized in Table 3-25. 

Table 3-25: Critical Inputs for Kitchen Undercabinet Lighting Energy Consumption and Savings 

Potential Estimate 

Critical Input Notes and Sources 

Installed Base of Lamps Percentage of Homes with Kitchen Undercabinet Lights: California 

Residential Lighting and Appliance Efficiency Saturation Survey, 

RLW Analytics, Inc., 2000, 2005. 

U.S. Household Population: 2000 Demographic Profile, U.S. Census 

Bureau. 

2000-2007 Residential Household Growth Rate: EIA’s Residential 

Energy Consumption Survey (RECS), 2001, 1997. 

Annual Operating Hours U.S. Lighting Market Characterization, Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a. 

Lamp Wattages Conventional Product Lamp Wattages: California Residential 

Lighting and Appliance Efficiency Saturation Survey, 2000, 2005; 

U.S. Lighting Market Characterization, Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a. 

Conventional Product Fixture Efficiencies: DOE Undercabinet 

Factsheet, 2008e. 

LED Product Efficacies: CALiPER Round 3 Summary Results, DOE, 

2007c. 

Lighting Technology Mix Conventional Technology Mix: U.S. Lighting Market 

Characterization, Volume I: National Lighting Inventory and Energy 

Consumption Estimate, DOE, 2002a; California Statewide and 

SMUD Residential Lighting and Appliance Efficiency Saturation 

Survey Database, RLW Analytics, Inc., 2005c, 2005d. 

3.6.2. Kitchen Undercabinet Lighting Installed Base 

We estimate an installed base of 53 million kitchen undercabinet lighting fixtures in the U.S., as 

shown in Table 3-26. The kitchen undercabinet installed base was determined using the 2000 

and 2005 California Residential Lighting and Appliance Efficiency Saturation Surveys. Using a 

linear projection between 2000 and 2005 data, we find that 26.1% of homes have kitchen 

undercabinets in California in 2007. Assuming that kitchen undercabinets are just as common in 

California as they are nationwide, we determined the national installed base of kitchen 

undercabinets by multiplying the average number of kitchen undercabinets per household in 

California by the number of U.S. households in 2007 (DOE, 2007a; EIA, 2001, 1997). An 

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online database from the 2005 IOU and SMUD survey was used estimate the market penetration 

of various undercabinet technologies in 2007 (RLW Analytics, 2005c, 2005d). 

Table 3-26: Kitchen Undercabinet Installed Base and Technology Mix, 200717 

Light Source Market Share (%) Installed Base 

General Service Incandescent 45.6% 24,340,000 

General Service Halogen 12.4% 6,620,000 

CFL – Screw Base 2.8% 1,474,000 

T12 Fluorescent Tube 34.0% 18,142,000 

T8 Fluorescent Tube 5.3% 2,806,000 

Total 100.0% 53,382,000 

3.6.3. Kitchen Undercabinet Lighting Operating Hours 

Kitchen undercabinet lighting systems operate for an average of 1107 hours per year, amounting 

to about three hours per day. This estimate comes from the U.S. Lighting Market 

Characterization Volume I: National Lighting Inventory and Energy Consumption Estimate 

(DOE, 2002a), which includes survey data on kitchen light operating hours. We assume that 

hours of operation have not changed between 2001 to 2007. 

3.6.4. Kitchen Undercabinet Lighting System Average Wattages 

Table 3-27 shows the average kitchen undercabinet lighting system wattage obtained from the 

2000 and 2005 California Residential Lighting and Appliance Efficiency Saturation Surveys. 

Using average ballast efficiencies for fluorescent lamps, system wattages for the kitchen 

undercabinet lighting systems could be calculated. LED replacements for the kitchen 

undercabinet lighting products were determined by matching the lumen output of the LEDs and 

conventional products, assuming a LED undercabinet lighting system efficacy of 45.5 lm/W 

from the best-in-class products measured by the CALiPER program (DOE, 2007c) and including 

measured undercabinet fixture efficiencies for LED and conventional products (DOE, 2008e). 

Table 3-27: Kitchen Undercabinet Lighting System Average Wattage and LED Equivalent 

Light Source System Watts (W) LED Equivalent (W) 

General Service Incandescent 60 9 

General Service Halogen 55 6 

CFL – Screw Base 18 8 

T12 Fluorescent Tube 45 13 

T8 Fluorescent Tube 28 20 

17 Due to lack of data, we assume that 4-foot T12s and T8s are most commonly used in kitchen undercabinets. 

However, less efficacious 2-foot or 3-foot fluorescents may also be in use in kitchen undercabinets. Therefore, we 

may be understating the energy consumption and potential energy savings of LEDs in this application. 

55 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.6.5. Kitchen Undercabinet Lighting Energy Saving Potential 

The 53 million kitchen undercabinet lighting systems in the U.S. consumed 2.84 TWh/yr of 

electricity, as shown in Table 3-28. LED kitchen undercabinet lighting systems did not lead to 

significant energy savings in 2007 as widespread adoption of LED products has yet to occur. 

However, the kitchen undercabinet lighting market has the potential to save 2.22 TWh/yr of 

electricity if the market completely shifted to LED systems with an average luminaire efficacy of 

45.5 lm/W (DOE, 2007c). This corresponds to 24.0 TBtu/yr of primary energy savings at the 

power plant, equivalent to 35% of the annual output of one large (1000 MW) coal power plant or 

annual electricity consumption of just under two hundred thousand households. 

Table 3-28: Kitchen Undercabinet Energy Consumption and Savings Potential, 2007 

Niche Application 

Annual Electricity 

Consumption 

2007 (TWh) 

Electricity 

Savings 2007 

(TWh) 

Potential 

Electricity 

Savings (TWh) 

Theoretical 

Maximum Electricity 

Savings (TWh) 

Kitchen Undercabinet 

Lighting 2.84 0.0 2.22 2.22 

3.6.6. Technology Benefits in Addition to Energy Savings 

White LEDs offer several advantages that will make them suitable to this niche application, as 

described in Table 1-2. LED light sources for kitchen undercabinet lighting offer several 

benefits and features to homeowners that set them apart from incandescent, halogen, and 

fluorescent products. These benefits include: 

1. Longer Operating Life 

2. Lower Maintenance and Life-Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

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4. Outdoor White-Light Applications 

As with indoor white-light applications, electricity is saved in outdoor white-light applications 

where LED sources are used to replace incandescent, halogen, mercury vapor, metal halide and 

high-pressure sodium lamps. The case for energy savings for outdoor white-light applications is 

unique from colored-light and indoor white-light applications because of the eye’s response to 

light under nighttime conditions. The savings for outdoor installations are presented in TWh per 

year for the nation under daytime conditions, which may represent the lower bound of the energy 

savings potential of LEDs in these applications. Even more energy could potentially be saved if 

lighting designers took into account the effects of night time conditions on vision. This report 

evaluates two outdoor white-light niche market applications: street and area lighting, and step, 

path, and porch lighting. 

4.1. Photopic vs. Scotopic Vision 

According to some experts, the energy efficiency benefits of LED outdoor lights cannot be 

determined simply by comparing efficacy, the energy efficiency measure for lamps. Studies 

comparing the perceived brightness of LED sources and sodium lamps at night have shown that 

LEDs can achieve the same level of perceived brightness with lower lumen output than sodium 

lamps (Raleigh 2007). This affect could be explained by the eye’s response to light in outdoor 

“night time” conditions. 

Light, measured in lumens, is defined according to the visual sensation it produces in “daytime” 

conditions. However, the visibility of light varies with external conditions. During “daytime” or 

indoor lighting conditions, where there is a high level of ambient light, the eye uses its cone 

sensors to perceive light. This type of vision is referred to as photopic (photon-rich) vision. 

During “night time” conditions, where there is a low level of ambient light, the eye uses its rod 

sensors to perceive light. This type of vision is referred to as scotopic (scarcity of photons) 

vision. The rods have a different color response than the cones in the eye, as shown in the 

photopic and scotopic V-λ curves, Figure 4-1. Under outdoor lighting at night, the eye operates 

in an intermediate range, called mesopic vision, using both rods and cones. 

The energy savings estimates given in this report could possibly be greater if the visible light 

output of light sources under outdoor lighting conditions were taken into account. Assuming 

equal quantities of “daytime” lumens produced, light sources rich in blue light, such as LEDs or 

metal halide lamps produce more visible lumens at night than light sources rich in yellow light 

such as high or low pressure sodium lamps (Bullough 2001). However, the commercial 

applicability of these additional energy savings is limited until regulatory bodies and the lighting 

industry change specifications and design requirements to take the efficacy of light sources under 

nighttime conditions into account. As of 2007, lighting organizations such as the Illuminating 

Engineering Society of North America (IESNA) and the International Commission on Lighting 

[Commission Internationale de l'Eclairage] (CIE) do not accept scotopically enhanced design 

factors as industry-recognized standard practice. 

57 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4-1: Photopic and Scotopic V-λ Curves
 

Source: Electro-Optical Industries, 2007.
 

4.2. Street and Area Lighting 

Streetlights serve the purpose of illuminating roadways, highways, or tunnels to improve 

visibility for drivers at night while area lights serve to illuminate outdoor sites such as parking 

lots and garages, outdoor landscapes, pedestrian walkways, and municipal and downtown 

common outdoor spaces. In this study, we took into account street and area lights that use 

incandescent, halogen quartz, fluorescent, and high intensity discharge lamps such as mercury 

vapor, metal halide or high-pressure sodium lamps as these represent the vast majority of street 

and area lights. 

Substantial energy savings can be realized if the market shifted toward LED street and area 

lights. A potential electricity savings of 44.7 TWh per year may be realized if LEDs achieved 

100% market penetration. The potential primary energy savings is 482.0 TBtu/yr at the power 

plant, the equivalent of seven large (1000 MW) electric power plants or the annual electricity 

consumption of 3.7 million households if 100% of the installed base moved to LED. 

4.2.1. Introduction 

The earliest street and area lights were oil or gas lamps that required a lamp-lighter to light each 

streetlight by hand at dusk. The first electric street and area lighting technology was the carbon 

arc lamp, invented by Pavel Yablochkov in 1875. A low voltage applied to the lamp’s two 

carbon electrodes produces an electric arc. As the two electrodes are pulled apart, an electric 

current maintains the arc and heats the electrodes until they incandesce and emit light. By the 

1890s, the United States had installed over 130,000 streetlights. 

In 1879, Thomas Edison invented the incandescent lamp, which soon replaced arc lamps for 

street and area lighting applications because of its higher reliability, longer life, and warm-white 

light. Incandescent lamps produce light by sending an electrical current through a tungsten 

filament, which heats until it incandesces to produce light. Incandescent street and area lights 

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were popular throughout the 1930s and 1940s as automobile use expanded. The incandescent 

lamp soon replaced the carbon arc lamp as the most common streetlight, because of the arc 

lamp’s harsher light quality and lower lamp life. 

In 1938, the first mercury vapor streetlights were installed. Mercury vapor lamps produce light 

by exciting mercury in a small quartz arc tube with an electrical current. The excited mercury 

then releases its energy by emitting light. Mercury vapor street and area lights became popular 

because they were much brighter and more efficient than incandescent lamps. However, the 

mercury contained in and ultraviolet light emitted by these lamps are safety hazards if the lamps 

break (Comer, 2000). 

In the 1970s, high-pressure sodium lamps, which produce light by exciting sodium, were put into 

service. These lamps are recognizable by their virtually monochromatic yellow/orange (589.0 

and 589.6 nm) light. High-pressure sodium lamps are beneficial because they are far more 

efficient than incandescent or mercury vapor lamps, and they contain no mercury. Today, 

yellow/orange high-pressure or low-pressure sodium lamps are among the most common street 

and area lighting technologies in use because of their high efficacies. Their main disadvantage is 

their poor color rendering because they are nearly monochromatic light sources (Comer, 2000). 

Metal halide is now becoming the light source of choice for street and area lighting applications 

where color rendering is important. A close variation of mercury vapor lamps, a metal halide 

lamp produces light through a mixture of mercury and other chemicals such as sodium iodide or 

scandium iodide in an excited state (Comer, 2000). Since a metal halide lamp’s spectrum 

contains more blue light than sodium lamps, they render blues and violets more accurately and 

appear to be brighter at night when the eye uses mesopic vision. 

In the early 2000s, researchers recognized the potential for LEDs in street and area lighting 

applications. LEDs are particularly advantageous in street and area lighting applications because 

they are better directional light sources, exhibit longer lifetimes, and enhance night time 

visibility. Because of these positive attributes, Raleigh, North Carolina became the first of a 

dozen U.S. cities to begin testing and replacing their conventional street and area lighting 

technologies with LED fixtures in February 2007. A major LED manufacturer has also launched 

the LED Cities program, to accelerate the adoption of LED technology in street and area lighting 

applications (CREE, 2007). In addition, DOE has launched the Gateway demonstration program 

to monitor LED products in many applications, including street and area lighting, and provide 

independent performance data.18 Although several cities have begun to adopt LED technologies 

in street and area light applications, we assume the penetration of LEDs is effectively zero as the 

number of LED streetlights these cities have installed amounts to less than one-tenth of one 

percent of the total installed base of streetlights in the U.S. 

A number of sources were contacted to prepare a national estimate of the energy consumption of 

street and area lights. Sources used for the four critical inputs to the energy consumption and 

savings estimates are summarized in Table 4-1. The analysis takes into account only those street 

and area lights that use incandescent, halogen quartz, fluorescent, and high intensity discharge 

18 Manufacturers and host sites may apply to participate in the program at 

http://www.netl.doe.gov/ssl/techdemos.htm. 

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lamps such as mercury vapor, metal halide or high-pressure sodium lamps as these represent the 

vast majority of street and area lights. 

Table 4-1: Critical Inputs for Street and Area Lighting Energy Consumption and Savings
 

Potential Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Street and Area Light Fixtures: U.S. Census Bureau, 

Electric Light Fixture Current Industrial Reports, 1980-2001 

Number of Lamps: NEMA HID Lamp Survey, 2004. 

Annual Operating Hours Street and area lights operate 12 hours per day throughout the year, 

amounting to 4,380 hours per year 

Lamp Wattages U.S. Lighting Market Characterization, Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a; NEMA 

HID Lamp Survey, 2004; GE, 2006; OSI, 2006; Philips, 2006. 

LED Efficacy: Cook, Sommer and Pang, 2008. 

Lighting Technology Mix U.S. Lighting Market Characterization, Volume I: National Lighting 

Inventory and Energy Consumption Estimate, DOE, 2002a. 

4.2.2. Street and Area Lighting Installed Base 

The installed base of street and area lights in the U.S. is approximately 131 million luminaires as 

of 2007, which includes 47.8 million area lighting fixtures, 45.8 million floodlighting fixtures, 

34.7 million street lighting fixtures, and 3.1 million parking lot/garage lighting fixtures. The 

national inventory of street and area lights was estimated from annual shipments of electric light 

fixtures collected by the U.S. Census Bureau until 2001 and the 2004 National Electrical 

Manufacturers Association (NEMA) High Intensity Discharge (HID) Lamp Survey, collected 

from 1990 to 2002. This study tracks annual HID lamp shipments in the U.S. by wattage and 

base types for the largest U.S. manufacturers. The street and area light inventory estimate 

assumes an average lifetime of 20 years for the street and area light fixtures. The technology 

mix of street and area lights was estimated from the lamp inventory developed from NEMA HID 

shipments data and from the U.S. Lighting Market Characterization, Volume I: National 

Lighting Inventory and Energy Consumption Estimate report. 

Table 4-2: Street and Area Light Installed Base, 2007 

Light Source Percentage Number of Street and 

Area Lights 

Incandescent 2% 3,159,000 

Halogen Quartz 8% 9,917,000 

Fluorescent 6% 7,530,000 

Mercury Vapor 13% 17,675,000 

Metal Halide 27% 38,330,000 

High Pressure Sodium 39% 54,745,000 

Total 100% 131,356,000 

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4.2.3. Street and Area Lighting Operating Hours 

The typical street or area light is run throughout the night, for 12 hours per day, amounting to 

4380 hours per year. 

4.2.4. Street and Area Lighting Average Wattages 

The conventional system wattages for the national street and area light installed base were 

developed from the 2004 NEMA HID Lamp Survey, and average fluorescent and HID ballast 

efficiencies and factors (GE, 2006; OSI, 2006; Philips, 2006), as shown in Table 4-3. The 

equivalent LED replacement wattages were developed by matching the lumens delivered by the 

conventional light source, using the best-in-class reported efficacies of street and area luminaire 

products tested by DOE’s Gateway demonstration program (Cook et al, 2008). The LED and 

conventional systems were matched on a mean lumen basis, taking into account the 30 to 50 

percent depreciation of light output from the fluorescent and HID sources over their respective 

lifetimes. 

Table 4-3: Lamp Wattage of Street and Area lights 

Light Source 

Conventional 2007 LED 

System Replacement 

Wattage (W) Wattage (W) 

Incandescent 150 26 

Halogen Quartz 150 31 

Fluorescent 159 151 

Mercury Vapor 254 108 

Metal Halide 458 327 

High Pressure Sodium 283 276 

4.2.5. Street and Area Lighting Energy Savings Potential 

Table 4-4 shows the potential energy savings if the national base of street and area lights was 

converted overnight to LEDs using 2007 technology. A potential electricity savings of 44.7 

TWh/yr may be realized if LEDs with an average luminaire efficacy of 57.5 lm/W (Cook et al, 

2008) achieved 100% market penetration. The potential primary energy savings is 482.0 

TBtu/yr at the power plant, the equivalent of seven large (1000 MW) electric power plants or the 

annual electricity consumption of 3.7 million residential households if 100% of the installed base 

moved to LED. 

Table 4-4: Energy Consumption and Savings Potential of LED Street and Area Lighting, 2007 

Niche Application 

Annual Electricity Electricity Potential Theoretical Maximum 

Consumption Savings 2007 Electricity Electricity Savings 

2007 (TWh) (TWh) Savings TWh) (TWh) 

Street and Area 

Lights 178.3 0 44.7 44.7 

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4.2.6. Technology Benefits in Addition to Energy Savings 

There are several benefits outside of energy savings that are driving the adoption of LED 

technology in this application. In addition to saving potentially 482.0 TBtu/yr of primary energy 

when the market reaches saturation, LED street and area lights offer other advantages over 

traditional technologies, as described in Table 1-2. These include: 

1. Longer Operating Life 

2. Lower Maintenance and Life-Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

7. Safety Improvements 

8. Uniform Illumination 

9. Improved Color Rendition 

10. Lower Lumen Depreciation 

11. Light Pollution Reduction 

4.3. Step, Path, and Porch Lighting 

A similar promising niche application for LEDs is residential step, path, and porch lighting. 

Several manufacturers have created specialized products for this application, with some designs 

winning the annual Lighting for Tomorrow prizes for innovative and energy-efficient LED 

product designs. Because products have only recently been introduced on the marketplace, we 

assume that market penetration for LEDs in this application is essentially zero. LED products 

are beneficial in this application because they provide enhanced nighttime visibility, longer 

lifetimes, and energy savings when replacing incandescent or halogen outdoor lighting. 

Step, path, and porch lighting consumed 22.0 TWh in 2007. An additional electricity savings of 

12.6 TWh/yr is possible if 100% of the market switched to LED products, equivalent to a 

primary energy savings of 136.3 TBtu/yr at the power plant. The theoretical maximum energy 

savings of LEDs in step, path and porch lighting is equivalent to the annual output of two 1000 

MW coal power plants or the annual electricity consumption of one million residential 

households. 

4.3.1. Introduction 

The task of residential step, path, or porch luminaires is to allow clear facial identification or 

identifiable walkway illumination near the lamp. These luminaires are usually wall-, step-, or 

path-mounted. The Illuminating Engineering Society of North America (IESNA) recommends 

that walkways and stairways average a horizontal illuminance level of about 0.5 footcandles (fc) 

(5 lux). The recommended level for vertical illuminance is 0.8 fc (8 lux), measured 5 feet (1.5 

meters) above the doorway threshold (LBL 2007). 

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Step, path, or porch luminaires face cooler operating temperatures because they are primarily 

used at night. LEDs are attractive for this application because they operate more efficiently in 

cooler temperatures (Shakir 2002). LEDs systems are also low-voltage, which enhances safety, 

and have small form factors, beneficial for applications in which the lighting system is designed 

to be inconspicuous. LED luminaires typically consume less power than incandescent or 

halogen systems, leading to substantial energy savings. LED products also have longer lifetimes, 

requiring less frequent lamp replacements. 

Previous studies, databases, and researchers were consulted to prepare an energy consumption 

and savings potential estimate for step, path, and porch lighting. As with the other niche market 

assessments, there are four critical inputs used in preparing the energy consumption and savings 

estimates, summarized in Table 4-5. The analysis takes into account the case of LED step, path, 

and porch lighting systems replacing incandescent and halogen outdoor luminaires. 

Table 4-5: Critical Inputs for Step, Path and Porch Light Energy Consumption and Savings
 

Potential Estimates
 

Critical Input Notes and Sources 

Installed Base of Lamps Number of Street and Area Light Fixtures: U.S. Census Bureau, 

Electric Light Fixture Current Industrial Reports, 1980-2001. 

Annual Operating Hours Operating Hours per Building Type: U.S. Lighting Market 

Characterization, Volume I: National Lighting Inventory and Energy 

Consumption Estimate, DOE, 2002a. 

Distribution of Building Types: Residential Energy Consumption 

Survey, EIA, 2001. 

Lamp Wattages California Residential Lighting and Appliance Efficiency Saturation 

Survey, RLW Analytics, Inc., 2000a, 2000b, 2005a, 2005b. 

Fixture Efficiencies: Mia Paget, PNL, 2008. 

LED product efficacies: CALiPER Round 4 Summary of Results, 

DOE, 2008c, CALiPER Round 3 Summary of Results, DOE, 2007c. 

Lighting Technology Mix California Residential Lighting and Appliance Efficiency Saturation 

Survey, RLW Analytics, Inc., 2000a, 2000b, 2005a, 2005b. 

4.3.2. Step, Path, and Porch Installed Base 

The national inventory of step, path, and porch lights was estimated from the U.S. Census 

Bureau’s Electric Light Fixture Current Industrial Reports, which tracked annual shipments of 

residential outdoor electric light fixtures until 2001. Extrapolating these inventories, by fixture 

type, to the national level in 2007 produces an estimated installed base of approximately 265 

million step, path, and porch lights, as shown in Table 4-6. The inventory assumes an average 

lifetime of 20 years for the step, path, and porch fixtures. 

The technology mix of the step, path, and porch lights was estimated from the 2000 and 2005 

California Residential Lighting and Appliance Efficiency Saturation Surveys (RLW, 2000a, 

2000b, 2005a, 2005b). Outdoor porch lights were one of the lighting fixtures tracked in the 

surveys of households in investor-owned utility and municipal utility districts in California. 

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Table 4-6: National Installed Base and Technology Mix of Step, Path and Porch Lights, 2007 

Light Source 

Percent of Number of 

Installed Base (%) Installations 

General Service Incandescent 75.0% 198,572,000 

Halogen General Service 6.7% 17,819,000 

Halogen Quartz 0.6% 1,526,000 

Fluorescent 0.3% 926,000 

CFL 17.3% 45,837,000 

Total 100% 264,680,000 

4.3.3. Step, Path, and Porch Operating Hours 

For this report, the average operating hours for step, path, and porch lights was estimated from 

the U.S. Lighting Market Characterization Volume I: National Lighting Inventory and Energy 

Consumption Estimate (DOE, 2002a). Outdoor residential spaces were one of the room-types 

tracked by this study. The Residential Energy Consumption Survey (RECS) published by the 

EIA, was used to obtain the distribution of building types in the residential sector. The average 

operating hours in outdoor residential spaces, weighted by lamp inventories, was 766 hours per 

year or approximately 2 hours per day for all lamp types. 

4.3.4. Step, Path, and Porch Lamp Average Wattages 

Table 4-7 shows the average lamp wattages for step, path, and porch lights which were estimated 

from the 2005 California Residential Lighting and Appliance Efficiency Saturation Surveys 

(RLW, 2000, 2005). From this study, lamp wattages for the residential sector were determined 

for outdoor porch applications. The replacement LED wattage was determined by matching the 

lumen output for the conventional technologies and LED products, given efficacies found from 

conventional lamp product catalogs and published efficacies from best-in-class LED outdoor 

products tested by the CALiPER program (DOE 2007,2008). Conventional outdoor luminaires 

have fixture efficiencies in the range of 40-80%; and for this energy consumption and savings 

calculation, a fixture efficiency of 60% was used to obtain the lumen output of the conventional 

products (Paget, 2008). Current LED outdoor residential step, path, and porch lighting systems 

are less efficacious than HID, fluorescent and CFL fixtures, thus LEDs are modeled to replace 

only incandescent and halogen fixtures, representing 82% or 218 million fixtures, in the energy 

savings analysis. 

Table 4-7: Average Lamp Wattage for Step, Path, and Porch Lights 

Lamp Type Average LED Replacement 

Wattage (W) Average Wattage (W) 

Incandescent General Service 119 46 

Halogen General Service 158 64 

Halogen Quartz 432 211 

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4.3.5. Step, Path, and Porch Lighting Energy Saving Potential 

The current market penetration of LEDs in step, path, and porch lights is assumed to be zero 

percent, as the technology has only recently become available in the marketplace. Table 4-8 

presents the energy consumption estimate for step, path, and porch downlights, based on the data 

and inventory estimates described above. 

Table 4-8: Step, Path and Porch Lighting Energy Consumption and Savings Estimate, 2007 

Application 

Annual 

Electricity 2007 

(TWh/yr) 

Electricity 

Savings 2007 

(TWh/yr) 

Potential 

Electricity Savings 

(TWh/yr) 

Theoretical Maximum 

Electricity Savings 

(TWh/yr) 

Step, Path, 

Porch Lighting 22.0 0 12.6 12.6 

Step, path, and porch lighting consumed 22.0 TWh in 2007. A potential electricity savings of 

12.6 TWh/yr is possible if all of the 217.9 million incandescent and halogen outdoor step, path, 

and porch lights were replaced with LED products with an average luminaire efficacy of 22.5 

lm/W (DOE, 2008c, 2007c). These potential electricity savings are equivalent to a primary 

energy savings of 136.3 TBtu/yr at the power plant. The maximum energy savings of LEDs in 

step, path and porch lighting is equivalent to the annual output of two large (1000 MW) electric 

power plants or the annual electricity consumption of one million households. 

4.3.6. Technology Benefits in Addition to Energy Savings 

In addition to energy savings, there are other benefits driving the adoption of LED technology in 

this application. In addition to saving potentially 136.3 TBtu/yr of primary energy when the 

market reaches saturation, LED step, path and porch lights offer other advantages over 

traditional technologies, as described in Table 1-2. These benefits include: 

1. Longer Operating Life 

2. Lower Maintenance and Life-Cycle Costs 

3. Reduced Radiated Heat 

4. Minimal Light Loss 

5. Dimmability and Controllability 

6. Directional Illumination 

7. Durability 

8. Light Pollution Reduction 

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5. Conclusion 

In the last few years, LEDs have emerged as a competitive lighting technology, capturing market 

share in several niche applications from incandescent, halogen, neon, high intensity discharge, 

and certain types of fluorescent light sources. Most cost-effective in colored-light applications, 

LEDs have proven to be an economically viable replacement in applications such as exit signs, 

where they are the least cost option, and traffic signal heads, where the initial LED light source 

can be more than 20 times as expensive as the incandescent light source it replaces while the 

lifetime costs are lower (ENERGY STAR, 2006). Furthermore, substitutions like these are taking 

place, without subsidies or coupon schemes, because LEDs make financial sense and offer 

customers a better quality, more reliable lighting service. 

Niche applications evaluated in this report cut across colored-light, indoor and outdoor whitelight installations. In the colored-light sector, LED technology is being used in traffic signal 

heads, decorative holiday lights, exit signs, and electric signage. In all of these applications, 

LEDs are replacing incandescent, fluorescent or neon lamps, which typically produce colored 

light using a color-filter lens or encasement. LEDs have the advantage of only producing light in 

the desired emission color, enabling them to do so using less energy. To date, approximately 

2.82 TWh of electricity are saved every year because of the LED traffic signals that have 

replaced incandescent technology. LED exit signs save even more electricity, 4.56 TWh per 

year, since they have become the technology of choice in this application. Substantial energy 

savings have also been realized through LED holiday lights and electric signage, saving 0.33 

TWh and 0.95 TWh per year, respectively. If these four colored-light applications switched 

entirely to LEDs, a potential of 15.2 TWh per year of electricity could be saved, equivalent to the 

annual output of approximately two large coal power plants or the annual electricity 

consumption of approximately one million typical U.S. households. 

In the indoor white-light installations, LED products are available for recessed downlights, 

refrigerated display cases, retail display lighting, task lighting, office undershelf, and kitchen 

undercabinet lighting fixtures. In all of these applications, LED products have only recently 

become available in the marketplace and we assume that there is no significant market 

penetration of LEDs as of 2007. In all of these applications, luminaire designers are taking 

advantage of the directional light output of LEDs to design highly efficient fixtures that have the 

potential to save substantial amounts of electricity. Indoor white-light applications have the 

greatest potential of all the applications studied in this report to save substantial amounts of 

energy. If the six indoor white-light applications switched entirely to LEDs, a potential of 108 

TWh per year of electricity could be saved, equivalent to the annual output of approximately 

seventeen large (1000 MW) electric power plants or the annual electricity consumption of nine 

million typical U.S. households. 

Finally, in the outdoor white-light applications, street and area lights represent the most 

significant niche market opportunity for LEDs. Designers can take advantage of the enhanced 

visibility of LEDs at night, due to their high blue content relative to high or low pressure sodium 

lamps. LEDs in outdoor white-light applications are the focus of major marketing programs 

such as LED Cities, DOE’s Gateway demonstration program, as well as the DOE ENERGY 

STAR® program for solid state lighting. A few pioneering cities have installed LED street and 

area lights and are reporting significant energy and cost savings, as well as better nighttime 

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visibility from white LED products compared to high-intensity discharge lamps. LED outdoor 

step, path, and porch light products have won the Lighting for Tomorrow prize for innovative, 

energy-saving SSL product design. As these programs gain in popularity, LED market share in 

these applications will grow. As of 2007, we assume that there is no significant market 

penetration of LEDs in these applications as LED products have just recently entered the market. 

However, if the market switched entirely to LEDs, street and area lights have the potential to 

save 44.7 TWh per year and outdoor step, path, and porch lights have the potential to save 12.6 

TWh per year of electricity, yielding a total of 57.3 TWh/year of electricity savings, the annual 

output of approximately nine large (1000 MW) electric power plants or the annual electricity 

consumption of almost five million households. 

Figure 5-1 presents the energy savings in 2007 from the niche applications considered in this 

analysis. The five niche applications appearing in this diagram represent those markets where 

LEDs have some level of market penetration. The other seven markets have an assumed market 

penetration of zero percent, due to the lack of significant market adoption as of 2007. 

Refrigerated Display

Cases

1% Commercial Signage

11%

Holiday Lights

4%

Traffic Signals

32%

Exit Signs

52%

8.7 TWh/yr

Figure 5-1: Site Electricity Savings in 2007 Attributable to LED Market Penetration 

Clearly exit signs are the dominant energy saver from an LED perspective in 2007, providing 

over half of the realized electricity savings. Other niches, such as traffic signals – the second 

most significant energy saver – contribute a third of the total site electricity savings in 2007. 

Some sectors such as refrigerated display case lighting have low levels of LED penetration, thus 

contribute only one percent to the 2007 savings. 

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Figure 5-2 apportions the electricity savings if 100% of these twelve niche markets convert to 

LED technology. This total represents the combined 2007 energy savings and future potential 

energy savings if the remainder of each market converts to LED luminaires with efficacies 

between 22.5 and 60.9 lm/W. This savings estimate may be understated, because it fixes LED 

technology at today’s performance levels. Over the coming years, researchers and manufacturers 

will continue to develop and commercialize more energy efficient, higher quality LED devices. 

This trend means that as more market share is captured in the future, the LED technology 

adopted will have better performance characteristics, and contribute to even more significant 

energy savings. This situation is particularly true for white-light LED devices, which today are 

significantly more efficacious than an incandescent, but are outperformed by the best T8 

fluorescent and high-intensity discharge lamps. White-light LED technology is presently the 

focus of many research initiatives around the United States and the world, and continued 

advancements in efficacy, lumen output, operating life, and other critical performance metrics 

are anticipated. 

Street and Area

Lights

24%

Step, Path, and Porch

lights

7%

Commercial Signage

4%

Office Undershelf

Lighting

0.7%

Kitchen

Undercabinet

Lighting

1%

Retail Display

4%

Task Lighting

7%

Refrigerated Display

Cases

1%

Recessed Downlights

42%

Traffic Signals

3%

Exit Signs

3%

Holiday Lights

3%

189 TWh/yr

Figure 5-2: Maximum Site Electricity Savings With 100% LED Market Penetration 

Table 5-1 summarizes the current energy savings of the analysis in detail, both electricity 

consumption and primary energy consumption. Some sectors have estimates of zero percent 

LED penetration, thus contribute no savings to the total of 8.7 TWh. Energy savings estimates 

were not prepared for seven applications analyzed: recessed downlights, retail display, task 

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lighting, office undershelf, kitchen undercabinet, street and area lights, and step path and porch 

lights. This was because significant adoption of LEDs has yet to occur. 

Table 5-1. Energy Consumption and Savings in 2007 of Applications Evaluated 

Application 

Annual Electricity LED Market 

Penetration 

Electricity Primary Energy 

Consumption Savings 2007 Savings 2007 

(TWh) (TWh) (TBtu) 

Colored Light Applications 

Traffic Signals 2.38 52% 2.82 30.4 

Decorative Holiday Lights 6.63 5.2% 0.33 3.53 

Exit Signs 2.50 88% 4.56 49.2 

Electric Signage 11.6 6.1% 0.95 10.3 

Indoor White-Light Applications 

Recessed Downlights 103.1 0.0% 0.0 0.0 

Refrigerated Display Cases 13.4 3.6% 0.08 0.81 

Retail Display 32.0 0.0% 0.0 0.0 

Task Lighting 18.8 0.0% 0.0 0.0 

Kitchen Under-Cabinet Lighting 2.84 0.0% 0.0 0.0 

Office Undershelf Lighting 3.43 0.0% 0.0 0.0 

Outdoor White-Light Applications 

Street and Area Lights 178.3 0.0% 0.0 0.0 

Step, Path, and Porch lights 22.0 0.0% 0.0 0.0 

Total 397 TWh -- 8.7 TWh 94 TBtu 

In 2007, electricity savings attributable to LEDs are dominated by exit signs, where LEDs have 

an estimated 88% market penetration. This niche market represents 52% of the total energy 

savings attributable to LEDs in 2007. The second most significant energy saving niche market in 

2007 was traffic signal heads. In this application, approximately 52% of the signals are 

estimated to be LED, representing approximately 32% of the total energy savings from LEDs in 

2007. From negligible penetration in 2002, LEDs have reached 6.1% of the electric signage 

market and 5.2% of the decorative holiday lights market, contributing to 11% and 4% of the total 

energy savings from LEDs in 2007, respectively. LEDs have also gained marketshare in the 

refrigerated display case market, achieving almost 4% penetration in 2007. Other applications, 

such as recessed downlights, retail display, task lighting, street and area lighting, and step, path 

and porch lighting are estimated to have zero market penetration of LEDs. Commercial LED 

products for these applications are available; however market adoption has yet to occur. 

Table 5-2 presents the future energy savings potential from converting the remainder of each 

market entirely to LEDs. It also presents the cumulative (total) energy savings that would result 

from the energy savings in 2007 and the additional energy savings from the conversion of each 

market to 100% LED. 

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Table 5-2. Potential and Cumulative Energy Savings of Applications Evaluated 

Application 

Electricity 

Savings 

Potential (TWh) 

Primary Energy 

Savings 

Potential (TBtu) 

Theoretical 

Maximum 

Electricity 

Savings (TWh) 

Theoretical 

Maximum 

Primary Energy 

Savings (TBtu) 

Colored Light Applications 

Traffic Signals 2.03 21.9 4.85 52.3 

Decorative Holiday Lights 5.97 64.4 6.30 67.9 

Exit Signs 0.63 6.78 5.18 55.9 

Electric Signage 6.58 71.1 7.53 81.3 

Indoor White-Light Applications 

Recessed Downlights 81.2 876.6 81.2 876.6 

Refrigerated Display Cases 2.0 21.6 2.1 22.4 

Retail Display 7.87 84.9 7.87 84.9 

Task Lighting 13.0 140.1 13.0 140.1 

Kitchen Under-Cabinet Lighting 2.22 24.0 2.22 24.0 

Office Undershelf Lighting 1.37 14.8 1.37 14.8 

Outdoor White-Light Applications 

Street and Area Lights 44.7 482.0 44.7 482.0 

Step, Path, and Porch lights 12.6 136.3 12.6 136.3 

Total 180 TWh 1944 TBtu 189 TWh 2039 TBtu 

Across the niche markets analyzed, there are significant opportunities for energy savings in the 

colored-light applications as well as the indoor and outdoor white-light applications. A total of 

15.2 TWh per year of potential site electricity savings are available in commercial advertising 

signs, traffic signals, holiday lights, exit signs and the other applications that are grid-connected. 

Similarly, 107.7 TWh per year of site electricity savings are available if the installed base of 

recessed downlights, refrigerated display cases, retail display lights, task lights, office 

undershelf, and kitchen undercabinet lights switched to LEDs. In the outdoor white-light market, 

57.3 TWh per year of site electricity savings are available in the street and area light and outdoor 

step, porch, and walkway applications. If these opportunities are fully realized, combined with 

the savings already captured to day, approximately 2039 TBtu of national energy consumption 

could be avoided. This represents 2.0 quadrillion Btus, “quads”, or approximately two percent of 

total national energy consumption in 2007. 

5.1. Benefits and Capturing Market Share 

LEDs offer many benefits that have enabled them to capture market share from conventional 

light sources. As discussed earlier, LEDs are proving successful at capturing market share in 

colored-light applications such as traffic signals and exit signs. Each niche market analyzed in 

this report covers the particular LED benefits that are most relevant to a given application. 

Benefits impacting multiple applications are summarized here: 

•	 Reduced Energy Consumption – LED devices can offer a more energy efficient means of 

producing light, particularly when compared to incandescent sources. In an application such 

as a traffic signal, an 8W LED red signal head replaces a 135W reflector lamp – a 94% 

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reduction in energy consumption - while complying with the same safety standards. And as 

solid state lighting technology evolves, the efficiency of these devices will continue to 

improve, enabling even greater energy savings through conversion to LED. 

•	 Long Operating Life – Commercial and industrial specifiers are generally interested in using 

a light source that is reliable and lasts a long time. Frequent lamp replacements can be costly 

from a maintenance perspective, and failed lamps could expose lamp operators to liabilities 

(e.g., traffic signals or exit signs). In fact, maintenance savings are one of the primary reasons 

behind market adoption of LEDs in several markets, such as electric signage, street and area 

lights, and retail display lighting. Presently, LED technology offers operating lives that are 

approximately twenty-five times longer than those of incandescent sources.19 Researchers 

indicate that operating life will continue to improve as the technology develops. 

•	 Lower Maintenance and Life-Cycle Costs - The longer life of LEDs translates into less 

frequent relamping and lower maintenance costs. Although several LED products cost more 

than conventional products, the lower energy consumption and extended operating life (and 

associated maintenance savings) equate to lower life-cycle costs. For example, the cost of 

ownership, including energy and maintenance costs, of one intersection of LED traffic 

signals is about ninety percent less than that of an intersection of incandescent traffic signals 

(ENERGY STAR, 2006, 2008a). 

•	 Reduced Radiated Heat – LEDs convert a higher proportion of electricity into visible light 

than incandescent sources. LED conversion efficiency has improved rapidly and is expected 

to continue; current LED luminaires can be equivalent to or more efficient than fluorescent 

and HID luminaires at converting power to visible light. Further, incandescent sources 

convert most of the power they use into infrared (IR) radiation (radiated heat), and some 

discharge sources emit both IR and ultraviolet (UV), but LEDs emit neither (unless 

specifically designed to do so). Instead, the waste heat generated by the LED must be 

removed by heat-conducting material (a “heat sink”). The reduction in heat radiated into 

conditioned space may reduce the air-conditioning or refrigeration load for some 

applications. 

•	 Minimal Light Loss – Unlike conventional lamps, LED luminaires do not need color filters 

to produce colored-light. In colored-light applications, light loss can be minimized by 

matching the color of the LED chip emitter to the color of the translucent covering on the 

lighting fixture. Furthermore, light emitted from an LED device is more directional and 

controlled, meaning that fewer photons are trapped within the lighting fixture. By contrast, 

conventional lamps have a 360 degree emission range, which results in lower fixture 

efficiencies as light is lost as the light is dispersed to the back of the fixture. 

•	 Dimmability and Controllability – For most applications, LED luminaires can be designed 

with dimming controls and motion sensors to adjust brightness levels. For example, LEDs 

can be dimmed more efficiently than fluorescents because rapid and frequent on/off cycles 

do not affect the life of the LED, enabling the use of movement-triggered controls. These 

19 We assume that manufacturers’ claims of 50,000-hour LED lifetimes can be substantiated. However, these claims 

have not been independently verified by DOE. 

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controls can reduce the annual operating hours of the LED system and lead to greater energy 

savings than we calculate in this report. 

•	 Directional Illumination – The LED sources can be targeted to illuminate particular parts of 

the packaging or prices in the display case, calling customer’s attention to aspects of the 

display case that may result in a sale. Similarly, LED task, office undershelf, or kitchen 

undercabinet lights can be targeted to illuminate particular parts of the work space, leading to 

higher fixture efficiencies and higher illumination to complete tasks, with less light scattered 

away from the work space. 

•	 Durability – the light production mechanism for LED devices is fundamentally different from 

traditional light sources such as incandescent and fluorescent. LED sources produce light by 

passing a current through thin layers of a semi-conductive material, which causes the 

recombination of electron-hole pairs in the material which emit light. Inherent in this solidstate light production mechanism is the ability of the source to resist vibration and impact, 

making it an ideal light source for refrigerated display cases, office undershelf and kitchen 

undercabinet lighting. The LED is encased in a tough epoxy plastic resin instead of a fragile 

glass bulb, thus, they are more resistant to shattering or impact damage in these applications. 

•	 Safety Improvements – For several applications, characteristics specific to LEDs lead to 

safety enhancements. LED luminaires are made of multiple diodes, and are less likely to fail 

simultaneously, leading to less down time for traffic signals, enhancing traffic flow and 

safety. In addition, LED holiday lights emit less heat than incandescents, and can reduce the 

current total of 210 home-structure fires per year due to ignited Christmas trees (Ahrens, 

2007). LED electric signage is also typically operated at lower voltages and direct current 

which are safer for maintenance workers to handle than neon, which operates at 12,000 to 

15,000 volts of alternating current. 

•	 Color Maintenance - Monochromatic LEDs for colored light applications allow the 

elimination of filters and hence better color control and color life than conventional 

technologies. 

•	 Smaller Package Size – Due to their compact size, LED devices are an excellent option 

where size or weight is a concern. For example, LED lighting provides more shelf space for 

merchandise in a refrigerated display case. This is because the LED and driver system is 

much smaller than a fluorescent lamp and ballast system, and can be distributed throughout 

the display case, unlike fluorescents. 

•	 Uniform Illumination. – LED devices offer distinct advantages where light encroachment or 

glare is a problem. For example, through the use of lenses and lighting controls, LED street 

and area lights, and step, path, and porch light luminaires can better distribute the light across 

the ground, allowing more uniform illumination. 

•	 Battery Back-Up Capability - Traffic signals that include red, green, and yellow LEDs 

consume around one-tenth as much power and LED exit signs consume about one-fifth as 

much power as with incandescent sources. For this reason, battery back-up power supplies 

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are available which can operate during power failures to ensure smooth flow of vehicular 

traffic or continuous delineation of building routes of egress. Many agencies use yellow LED 

signals for battery back-up reasons in emergency situations. For instance, if yellow LED 

signals were used in flashing mode, work crews would have a few extra hours to handle 

emergency situations (Bullough, 2003b). 

•	 Adjustable Color – Storeowners could also easily alter the intensity and color of the LED 

light to augment particular colors in the products. Recent marketing studies have shown that 

these features offer enhanced appeal to the human eye compared to other lighting systems. 

Study subjects strongly preferred display cases with LED lighting systems at half the 

illumination levels of fluorescent systems (Narendran, 2003b). 

•	 Light Pollution Reduction – The directional quality of LED street and area or step, path, and 

porch luminaires leads to more lumens to light the road plane or path and fewer lumens 

scattered upward, reducing light pollution. 

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Office of Energy Efficiency and Renewable Energy