2/17/2009 12:00:00 AM<< Back to Facilities Management Lighting Category Home
The T8 Ballast: Not Every Ballast Is Created Equal
Compiled by FacilitiesNet Staff
Not every T8 ballast is created equal. Though T8 ballast selection was a relatively easy task with the first generation of T8 ballast technology, the introduction of occupancy sensors, dimming ballasts, and T8 lamps that save more energy than a standard 32 watt T8 lamp, make it all the more important to pick the right T8 ballast for the job.
Pick the wrong T8 ballast and a system may not operate as envisioned — lamps could require frequent replacement or light output might not match projections.
Matching lamps with the proper ballasts is especially important when occupancy sensors are used. In the past, a common choice was to combine an occupancy sensor with an instant-start ballast and a standard T8 lamp. In an instant-start ballast, the lamp electrodes are unheated, which uses less energy than other designs. To make up for the lack of heating, the instant-start ballast uses a higher starting voltage. Such a choice might not be appropriate for a system that uses occupancy sensors because the instant-start ballasts put more wear on the lamps, shortening their life. In such a case, a programmed start ballast might be better choice.
Programmed start ballasts also work well in dimming applications, because as a lamp is dimmed, the electrodes cool. Programmed-start ballasts can heat the electrodes as they cool, prolonging lamp life.
The Next Generation T8 Ballast
Finally, it's important to remember that high-performance T8 lighting, using more efficient lamps and ballasts than early generations of T8 lamps, can cut energy use by 7 to 17 percent while providing the same illumination.
Replacing early T8 systems with new electronic ballasts and lamps won’t create the same kinds of savings as when they made the switch from T12 to T8. But new ballasts that work with occupancy sensors and dimmers also offer control options that were unavailable previously.
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