How to Buy an Energy-Efficient Fluorescent Tube Lamp

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

Efficiency Recommendation
Cost-Effectiveness Example
Where to Find

Also provided is a portable document format version of How to Buy an Energy-Efficient Fluorescent Tube Lamp (PDF 66 KB, 2 pp). Download Adobe Reader.

Efficiency Recommendation
Lamp Type	Recommended	Best Available
Four-Foot Lamps
T8, 32 watts	2800 lumens^a or more	3000 lumens
T12, 34 watts	2800 lumens or more	2900 lumens
Eight-Foot Lamps
T8,59 watts	5700 lumens or more	5950 lumens
T12,34 watts	2800 lumens or more	2900 lumens
Eight-Foot Lamps
T8,59 watts	5700 lumens or more	5950 lumens
T12,60 watts	5600 lumens or more	6000 lumens
U-Tube Lamps
T8/U,31-32 watts	2600 lumens or more	2850 lumens
T12/U,34 watts	2700 lumens or more	2760 lumens

^a Lumen is a measure of light output.

Cost-Effectiveness Example
Performance	Base Model	Recommended Level	Best Available
Lamp and Ballast Type	T12,34 watts, magnetic ballast	T8,32 watts, electronic ballast	T8,32 watts, electronic ballast
Rated Lamp Output - 2 Lamps	5300 lumens	5600 lumens	6000 lumens
Actual Light Output with Ballast^a	4738 lumens	5018 lumens	5256 lumens
Input Power	82 watts	62 watts	57 watts
Annual Energy Usage	295 kWh	223 kWh	205 kWh
Annual Energy Cost	$17.70	$13.40	$12.30
Annual Energy Cost Savings - 2 Lamps + Ballast	—	$4.30	$5.40
Annual Energy Cost - 2 Lamps Only	—	$1.30	$1.80
Lifetime Energy Cost Savings - per Lamp^b	—	$2.80	$3.90

^a Not including fixture performance, which affects total light output from the luminaire.
^b Lifetime energy cost savings is the sum of the discounted value of annual energy cost savings based on average usage and an assumed lamp life of 5 years. Future energy price trends and a discount rate of 3.4% are based on federal guidelines (effective from April 2000 to March 2001).

Cost-Effectiveness Assumptions: Usage assumption is 3,600 operating hours/year. Assumed electricity price: $0.06/kWh, the Federal average electricity price in the U.S.

Energy use and performance of a fluorescent lamp depends on the performance of the ballast(s) and the fixture which, together with the lamps, make up a luminaire Ballast Efficiency Recommendation. This example examines the cost-effectiveness of choosing energy efficient fluorescent lamps and ballasts. The example also shows the lifetime energy cost savings for improved lamps alone, net of the savings from improved ballasts. Each case evaluates energy use by two lamps matched with an appropriate two-lamp ballast, selected to provide a similar level of light output.

Where to Find Energy-Efficient Fluorescent Tube Lamps

The Federal supply sources for energy-efficient fluorescent lamps are the Defense Logistics Agency (DLA) and the General Services Administration (GSA). DLA sells fluorescent tubes through its Energy Efficient Lighting catalog, available on its Web site. GSA offers them on Schedule 62-II, as well as through its on-line shopping network, GSA Advantage! Choose lamps that meet the recommended levels.

When contracting or buying from a commercial source, specify or select a lamp lumen rating that meets the Efficiency Recommendation for that lamp type and wattage.

Buyer Tips

Lamps and ballasts should be upgraded together to insure compatibility and energy savings. Four-foot T8, 32 watt lamps are preferred over four-foot T12, 34 watt ("reduced wattage") lamps to take advantage of a wider selection of efficient ballast models (see Ballast Efficiency Recommendation). Reduced wattage T12 lamps are unsuitable for low-temperature applications due to starting difficulties in cold conditions.

Fluorescent lamps should have a color rendering index (CRI)^a of at least 70 for most commercial applications. "Rare-earth phosphor" fluorescent lamps usually have high CRIs and meet the levels of this efficiency recommendation; many efficient lamps with other phosphor types have CRIs below 70.

Due to their mercury content, most spent fluorescent tube lamps are classified as hazardous waste in most states under the Resource Conservation and Recovery Act (RCRA). However, some models are manufactured with a low enough mercury content (under about 10 micrograms per lamp) to be exempted from this hazardous classification. Also, many companies offer lamp recycling services.

^aColor Rendering Index (CRI) measures of the quality of color rendition compared with a reference light source of comparable color temperature. CRI has a maximum of 100.

For More Information

FEMP's Federal Lighting Guide (PDF 1.7 MB, 53 pp) provides helpful guidance on lighting projects.
Phone: (877) 337-3463. Download Adobe Reader.
American Council for an Energy-Efficient Economy (ACEEE) publishes the Guide to Energy-Efficient Commercial Equipment, which includes a chapter on lighting.
Phone: (202) 429-0063
The Lighting Research Center has valuable information covering various lighting systems.
Phone: (518) 276-8716
E SOURCE publishes Lighting Technology Atlas (available to member organizations).
Phone: (303) 440-8500
Lawrence Berkeley National Laboratory provided supporting analysis for this recommendation.
Phone: (202) 646-7950