Last month, we reviewed how lighting systems only five to 10 years old may become even more energy efficient by applying lighting technologies developed in the past few years. We saw how the new GE T8 Watt Miser lamp can save 2 more watts/lamp without changing ballasts, and that several firms now offer fixtures with built-in sensors to dim lights in stairwells when unoccupied. Many other new lighting technologies have proven themselves in the field, offering answers to problems that could not be cost-effectively solved only a few years ago.
Some new high-bay fixtures instead use several (up to eight) large, compact fluorescent lamps (CFL) in each fixture, surrounded by a computer-designed reflector to concentrate their output. A single fixture using multiple 42-W CFLs provides the same output as a single 250-W metal halide fixture using the same total wattage. It does so, however, without the long startup/restart period, major lumen depreciation over time, color shift, or safety hazard inherent in many HID lamps.