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From LED to CFL, an alphabet soup of energy-efficient lightbulbs

Just as the lights were dimming on the incandescent bulb, its future is flickering with hope once again. • In July, Congress reopened the debate over whether the shift to energy-efficient alternatives is smart environmental policy or merely governmental intrusion into citizens' lives. Never mind that a 2007 law signed by then-President George W. Bush called for all incandescent lightbulbs to be phased out between 2012 and 2014 "to move the United States toward greater energy independence and security." • With renewed questions about what kind of bulbs are best, here's an overview of the somewhat overwhelming number of options. And as consumer choices seem to expand with every passing month, here are considerations for shoppers trying to sort out what they see on store shelves:

Energy efficiency

The reason incandescent bulbs were to be phased out is energy efficiency.

Lighting accounts for 10 percent of household energy use, and the incandescent bulbs are simply inefficient: 90 percent of the energy they produce is lost as heat.

Three alternative technologies are currently available. Halogen bulbs use about 25 percent less energy than traditional incandescents and last up to three times longer. Compact fluorescent lamps, or CFLs, use about 75 percent less energy and last up to 10 times longer. Light-emitting diodes, or LEDs, use 80 percent less energy and can last the longest — up to 25 years.


The alternatives cost more up front. At a big-box hardware store a 60-watt incandescent bulb is about 60 cents when bought in a multipack. An equivalent halogen bulb might cost $1.50. An equivalent CFL is $2 to $5, while an LED is $34 to $40.

All three alternatives deliver great savings in the cost of operation. A 60-watt incandescent bulb costs about $4.80 per year to light, according to the Department of Energy. An equivalent halogen bulb costs $3.50 a year, a CFL costs $1.20 and a LED costs $1.

How they work

Incandescent bulbs have a filament that's heated by electricity until it glows. A halogen bulb works similarly, except the filament is inside a halogen gas capsule.

CFLs drive an electric current through a phosphor-coated glass tube that contains argon and a tiny amount of mercury. The mercury absorbs the electric current and prompts the phosphor to glow, creating light. CFLs take time to reach full brightness because that chemical reaction needs extra electricity when the bulb is first turned on.

LEDs are electronics. They're illuminated by the movement of electrons inside a diode.

Light quality

Most Americans have grown up with incandescent lights, which mimic natural sunlight and have a golden hue. They are dimmable.

Halogen bulbs have an almost identical light quality and are dimmable.

CFLs have long had light that is more blue — some would say unnatural or harsh. Many companies offer bulbs with different color phosphor blends designed to look more natural. Dimmable CFLs are increasingly available.

LEDs can mimic the hue of incandescents because their colors are tuned electronically. LEDs are dimmable.


Incandescent bulbs come in all shapes, wattages and colors. Consumers have few options with CFLs and even fewer with LEDs, but choices are growing and prices are dropping.


In many cities, incandescent and halogen bulbs can be thrown away, but CFLs and LEDs need special treatment. CFLs contain mercury and must be taken to a recycling center. LEDs must be disposed of as electronic waste.

From LED to CFL, an alphabet soup of energy-efficient lightbulbs 09/10/11 [Last modified: Saturday, September 10, 2011 4:32am]
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