The standard 100-watt light bulb is going away, and its lower-wattage cousins are soon to follow.
U.S. bulbmakers can no longer manufacture the 100-watt bulb as of Saturday -- part of a multiyear push to boost the efficiency of the nation's lighting under a 2007 law signed by President George W. Bush.
For consumers, the law is making the purchase of light bulbs more like an investment choice, with a need to balance higher up-front costs against longer-term electricity savings.
Some of the newest high-efficiency bulbs cost more than $20 each and are designed to last more than 20 years.
"The light bulb is moving from a 60-cent commodity that you throw into your grocery cart to an investment just like a refrigerator or major appliance," said Terry McGowan, director of engineering for the American Lighting Association, an industry trade group. "It costs more money and you expect it to do more, and if you move, you might even take it with you."
Consumers will still see the old-style bulbs on shelves for some time. Lower-wattage incandescent bulbs are being phased out over the next two years. The law allows stores to sell remaining stocks of banned bulbs.
Replacement bulbs using halogen and other technologies are already on store shelves. The incandescent bulb, with its tungsten filament, was a breakthrough in lighting 100 years ago, a vast improvement over the 19th-century designs of Thomas Edison and others. Its shortcoming is that only 10 percent of the energy is converted to light, with the rest lost as heat.
Industry supports change