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 |
 |
Buyer Tips For More Information |
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 lumensa 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 Ballasta | 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 Lampb | — | $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