Energy-Saving Lighting and Lighting Sensors
Dave Carlson, dc196@columbia.edu
Director of Project Engineering, Columbia Facilities

For about 15 years, the University has been replacing incandescent lighting with more efficient, longer-lasting fluorescent bulbs. The only remaining incandescent lighting is in some special applications and decorative chandeliers, where it’s impractical to replace the warm feeling and decorative look of incandescence. However, new technology is making these replacements more feasible in the future.

In compact fluorescent lighting (designed to replaced incandescent bulbs), the ballast is actually configured into the base of the bulb. This, in contrast to traditional fluorescent lighting in which the ballast is part of the fixture that holds the fluorescent tube, not part of the tube itself.

The environmental benefit of fluorescent lighting rests in its energy savings. One 27-watt fluorescent light has the same light output as one 100-watt incandescent bulb, translating into a near 75 percent energy savings. This means less energy and the pollutants and green house gases associated with producing that electricity. In fact, the life span of a 27-watt compact fluorescent bulb will save more than 1000 pounds of carbon dioxide from being released into the atmosphere when compared with the 100 watt bulb. Moreover, the conventional incandescent bulb lasts for 750 hours, while the fluorescent one lives to the ripe old age of 10,000 hours.

On the Morningside campus, lighting controls include timers in most academic spaces. These devices prevent lights from being left on overnight and are usually programmed for 10-to-12 hour control settings. Recent technology improvements have made occupancy sensors much more reliable than they have been in the past in determining whether a space is truly vacant and switching off lights accordingly. The University will move to this newer, more-sophisticated type of lighting control on new construction projects.


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