CEE’s Commercial Lighting Committee is drafting a specification for low-wattage T8 systems that could supplement the High-Performance Commercial Lighting Systems Initiative. At present, the initiative addresses only higher-lumen, 4-foot, 32-watt T8 lighting systems.

Reduced-wattage T8s are not as universally appropriate as high-performance T8 systems, and members are working to provide appropriate guidance on some of the application constraints. Reduced-wattage lamps are sensitive to colder temperatures, have a slightly reduced life and are not compatible with dimming ballasts or occupancy sensors.

In retrofit situations, however, the lamps being replaced are often T12s or standard-performance T8s; low-wattage T8s generally provide the same amount of light and level of performance while saving significant amounts of electricity.

Low-wattage T8s are available in 30-, 28- and 25-watt versions. In terms of light output, the reduced-wattage T8s are equivalent to 34-watt T12 Energy Savers.

“Low-wattage T8s are not appropriate in all situations but in retrofits, they can make sense as an efficiency measure,” said CEE Program Associate Susan Loucks, who is managing the commercial lighting initiative.

“For new construction, high-performance T8s are usually the better choice because the increased light output can mean fewer fixtures and more flexibility with controls and temperature. But for retrofits, the low-wattage lamps can be a simple, cost-effective solution.”

Several CEE members – including Efficiency Vermont, NSTAR and Xcel Energy – are providing incentives for low-wattage T8s in their commercial lighting programs. These products are also being marketed by many major lighting manufacturers.

At CEE’s June Program Meeting, Ira Krepchin of E Source, a consulting firm, examined the pros and cons of low-wattage T8s. He noted that energy savings and ease of installation are major advantages, and low-wattage T8s can also be useful in areas that are over-lit. In some cases, the ballast does not need to be replaced.

Krepchin did note that low-wattage T8s sometimes “provide less incentive for later, more comprehensive, upgrades.”

He finished up his presentation by saying that reduced-wattage lamps are “here to stay.” Although they have limitations, he added, low-wattage T8s can be cost-effective in certain retrofit applications.

The Commercial Lighting Committee is currently working on a draft specification for low-wattage T8s and is hoping to distribute it for industry comment in the fall. “There is a lot of confusion in the market about low-wattage T8s.” said Loucks.

“The Commercial Lighting Committee is trying to provide information that will allow designers to broaden their choices for lighting – without losing light quality and performance.”

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