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Study Finds Spectrally Enhanced Lighting Brings Energy Savings
A new report documents field test evaluation results of spectrally enhanced lighting technology used in three buildings.
The report, released by the U.S. Department of Energy (DOE), finds that spectrally enhanced lighting use can save 20 percent more energy than commonly used electronic ballasted T8 fluorescent lighting systems. Properly designed systems can achieve 50 percent savings over T12 and magnetically ballasted lighting systems.
The DOE and the Pacific Gas and Electric Company jointly sponsored a rigorous field study that compared two floors of an office building, one retrofit with 3500K, 82 CRI lamps and the other retrofit with 5000K, 82 CRI lamps with reduced lighting levels set to result in equal visual acuity. The results of this study were that energy savings were realized and there was no difference in occupant acceptance between the two floors.
As a follow-up, the DOE performed a comprehensive field test in 2005 using three independent buildings that were entirely retrofitted with 5000K, 82 CRI lamps. In this study, it was determined that energy savings of approximately 20 percent are obtainable for T8 to T8 retrofits and 50 percent for T12 to T8 retrofits. The field study also concluded that there was no difference in occupant satisfaction between the old and new lighting, nor was there any increase in the use of task lighting as a result of the decrease in illumination levels.
Energy savings are obtained by using lamps that have a higher S/P ratio, and then determining the setting for the light levels that will result in equal visual acuity. For instance, if the visual benefit from the enhanced spectrum is 20 percent, the lighting levels could be reduced by 20 percent to obtain the same reading ability, which therefore results in a 20 percent savings in energy.
The cumulative and progressive results of these studies demonstrate that Spectrally Enhanced Lighting can provide significant energy savings without risk of occupant rejection or dissatisfaction, the DOE says.