High Performance Schools Exchange E-zine

Building Components: Super T8 Fluorescent Lighting

A new fluorescent T8 lamp and electronic ballast lighting system is coming on the market. Its advantages in energy efficiency, longer lamp life, and improved lumen depreciation are such that it will likely become the prudent choice for recessed troffers in new construction. In fact, with long operating hours, it may be cost effective to retrofit even existing T8 electronically ballasted lighting with this new system.

The new system is often called "Super T8s." The lamp and ballast manufacturers use terms like:

• AccuStart (from Universal; see http://www.universalballast.com/literature/flyers/Accustart_flyer.pdf )
• Optanium (from Philips/Advance; see http://www.advancetransformer.com/Literature/pdf/Advance_Insider_Lightfair_2003.pdf)
• UltraMax (from General Electric; see: http://www.gelighting.com/na/litlib/ultramax_ballasts.html)
• Xtreme (from Sylvania/Osram; see: http://www.sylvania.com/business/hot/fluorescent/xtreme.htm)

The technological advance is largely attributed to a "program start ballast" that allows the lamp to be lit with a softer start up than the present instant start T8 ballast. The lamp cathode is not punished as severely with the inrush of current. This allows the rated life of the lamp to increase from 20,000 hours to 30,000 hours in most cases. It also means less tungsten from the cathode is shed within the lamp, resulting in the lamp losing light output over its life by around six percent rather than 15 to 25 percent. The Super T8 lamp is also new. It is a high color rendering lamp (80+ CRI), has improved lumen depreciation (94%+), and has improved efficacy (90 mean Lu per watt).

Keep in mind this is a new product. Reliable information on new technologies can be hard to come by - and can be confusing. Lamp and ballast manufactures are not standardized yet in their products' operating characteristics - it is difficult to compare products as apples to apples. What we do know through our utilities and system benefit charge administrators is something about their typical energy use:

Rated fluorescent lighting system wattage	Typical older system (EE T12 lamps & en. eff. magnetic ballasts)	Standard T8 system (T8 lamps/ electronic ballast)	"Super T8" system (approved T8 lamp/programmed start electronic ballast)
2-lamp fixture	70	60	47
3-lamp fixture	110	88	67
4-lamp fixture	140	112	89

This means that with a weekly burn time of 75 hours and electricity priced at 10 cents per kWh, a Super T8 four-lamp fixture would save $20 per year in operating costs over energy efficient T12s and energy efficient magnetic ballasts ($9 over the T8s and electronic ballast we have been using now for 15 years). With a Super T8 system costing +10 to 15 percent in material costs, the payback is attractive. Additionally, some electric utilities offer increased rebates for Super T8s (National Grid, for example, offers an extra $5 rebate).

If this has you interested in learning more, the best next step would be to contact your electric utility or system benefit charge administrator (e.g., Efficiency Maine, Efficiency Vermont) to ask their assistance in your evaluation of this new product.