Skip Navigation to main content U.S. Department of Energy U.S. Department of Energy Energy Efficiency and Renewable Energy
Bringing you a prosperous future where energy is clean, abundant, reliable, and affordable EERE Home
Federal Energy Management Program
 
About the ProgramProgram AreasInformation ResourcesFinancing MechanismsTechnologiesServicesHome
Energy-Efficient Products Home Page
Energy Efficiency Requirements
Energy Cost Calculators
Model Language
Resources

How to Buy an Energy-Efficient Fluorescent Luminaire

Information about energy-efficient fluorescent luminaires in this section includes the following:

Efficiency Recommendation
Cost-Effectiveness Example
Where to Find		 Buyer Tips
Design Considerations
For More Information

Also provided is a portable document format version of How to Buy Energy-Efficient Fluorescent Luminaires (PDF 72 KB, 2 pp). Download Adobe Reader.

Efficiency Recommendationa
Luminairea Type
(NEMA Designation)		 Number of Lamps Recommended LERb Best Available LERb
2' x 4' Recessed
Lensed (FL) 2 62 or higher 77
3 61 or higher 77
4 61 or higher 77
VDTc-Preferredd
Louvered (FP)		 2 50 or higher 62
3 51 or higher 68
4 54 or higher 68
Plastic Wraparound
Four-Foot (FW) 2 63 or higher 88
4 62 or higher 100
Strip Lights
Four-Foot (FS) 1 70 or higher 86
2 70 or higher 92
Industrial
Four-Foot (FI) 1 67 or higher 91
Eight-Foot (FI) 2 68 or higher 86
2' x 2' Recessed, for U-Tube Lamps
VDT-Preferred 2 41 or higher 63
Lensed 2 49 or higher 78

a Luminaire is a complete lighting unit consisting of a fixture along with one or more ballasts and lamps.
b Luminaire efficacy rating (LER) describes the efficiency of a luminaire in terms of rated light output (in lumens) per watt of electricity use. (Lumen is a measure of light output.)
c VDTs or video display terminals (computer monitors) may be obscured by direct or reflected glare from overhead luminaires that emit light at wide angles.
d "VDT-Preferred" luminaires meet IESNA recommendations for glare reduction (See For More Information), based on maximum allowable average luminance at 55° and higher angles from vertical.

Back to Top

Cost-Effectiveness Example
Performance Base Model Recommended Level Best Available
Luminaire Efficacy Rating (LER) 32 62 77
Luminaire Light Output 3600 lumens 3700 lumens 4400 lumens
Power Input 113 watts 60 watts 57 watts
Annual Energy Use 407 kWh 216 kWh 205 kWh
Annual Energy Cost $24 $13 $12
Lifetime Energy Costa $260 $140 $130
Lifetime Energy Cost Savings — $120 $130

a Lifetime energy cost is the sum of the discounted value of annual energy costs based on average usage and an assumed luminaire life of 15 years. Future electricity price trends and a discount rate of 3.4% are based on federal guidelines (effective from April 2000 to March 2001)

Cost-Effectiveness Assumptions: This example shows the cost effectiveness of energy-efficient 2' x 4' recessed, lensed luminaires. The base model uses three 34-watt T-12 lamps, while the recommended and best available models, despite providing equivalent or greater light output (lumens), use only two 32-watt T8s. Usage assumption: 3,600 operating hours per year. Three sets of lamps would be used over the assumed luminaire lifespan of 15 years. Assumed electricity price: $0.06/kWh, the federal average electricity price in the U.S.

Metric Conversions:
1 Ton = 12,000 Btu/h
1,000 Btu/h = 293 watts
°F = (1.8 * °C) + 32
1 Foot = 30.5 cm

Back to Top

Where to Find Energy-Efficient Luminaires

The Federal supply sources for fluorescent luminaires are the Defense Logistics Agency (DLA) and the General Services Administration (GSA). DLA sells luminaires through its Energy Efficient Lighting catalogue, available on its Web site. GSA offers them on Schedule 62-II, as well as through its on-line shopping network, GSA Advantage! Select or specify models that meet the recommended level for that luminaire type and lamp number.

Back to Top

Buyer Tips

Federal buyers should select or specify luminaires with Luminaire Efficiency Ratings (LERs) that meet the recommended levels, based on industry standard tests. However, the LER rating may not be available for some manufacturers' products. If an LER rating is not available, it can be estimated from other photometric data using this formula:

LER equals Total Rated Lamp Lumens times Ballast Factor times Luminaire Efficiency divided by Input Watts

¹Ballast factor (BF) is the ratio of the light output of lamp(s) operated by a ballast to the light output of the same lamp(s) operated at rated current and voltage. Also called Relative Light Output (RLO).
²Luminaire efficiency (LE) is the luminaire's light output, in lumens, divided by the total rated lamp lumens.

Rated lamp lumens, ballast factor, and luminaire efficiency may be found in manufacturers' luminaire photometric reports and in some catalogues.

Back to Top

Design Considerations

Lighting energy savings depend on good lighting design and controls, as well as efficient luminaires. A lighting designer can assist with proper luminaire selection, placement, and choice of occupancy or daylighting controls.

"VDT-preferred" luminaires, while reducing glare on computer screens, may be less efficient than other models. Where greatly reduced glare is not a design need, look for either a VDT-compatible luminaire with a higher LER, or an efficient non-VDT-rated model. Other special situations, such as equipment with high sensitivity to electromagnetic interference or the need for vandal-proof fixtures, may also compromise efficiency.

Back to Top

For More Information

Back to Top