CFLs have many pros – and a few cons

Life span: Today's CFLs have life spans of 6,000 to 15,000 hours, while standard incandescent bulbs are usually rated at around 1,000 hours. Under Energy Star guidelines, a lamp rated at 6,000 hours corresponds to a warranty of five years, while one rated at 15,000 hours corresponds to a warranty of 15 years (based on residential use for a minimum use of three hours a day).

Color rendition: While CFLs are superior to incandescents in many regards, one relative weakness is color rendition, as CFLs do not offer the full spectrum of light (though technology advancements continue to improve this aspect). The Color Rendering Index (CRI) is a scale of zero to 100, and incandescents are usually rated at the top, meaning they can fully render the colors of the objects they illuminate. For Energy Star compliance, CFLs must achieve a CRI of above 80.

Frequent on/off cycling: Some experts maintain that CFLs perform best when left on for long periods of time, as opposed to constantly being switched on and off. In other words, a CFL's lifespan may be reduced by frequent on/off cycling. While this by no means precludes the use of CFLs in residential applications, it does mean that commercial applications may get the most bang for the buck, especially if the lights in these environments are left on for long periods of time. For Energy Star compliance, lamps go through a rapid cycle stress test where each model must withstand a minimum number of on/off cycles, based on one cycle of five minutes on, and five minutes off, for every two hours of the lamp's rated life.

Disposal: CFLs necessarily contain a very small amount of mercury, which is in no danger of being released into the environment through normal use. Yet because of this content, CFLs should be disposed of in a proper manner. The federal Energy Star program recommends two sites, www.earth911.org and www.lamprecycle.org, for consumers to visit to find locally available disposal options. While there are no disposal programs currently available in South Carolina, options elsewhere increasingly include retailer take-back programs. IKEA is one example and Wal-Mart has run trial programs in other states.

Source: Cooperative Research Network

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