Last December, President Bush signed into law an energy bill that, among other things, raises automobile fuel-efficiency standards for the first time in 30 years. Buried in the bill was a little-noticed provision that phases out incandescent light bulbs over the next four to 12 years in favor of more energy-efficient technology.

Like other product categories, lighting has been put under a microscope due to the continued growth of sustainable building. Architects hoping to achieve LEED status or building to Energy Star qualifications must ensure that lighting sips rather than swills power. But as the bulb phaseout begins, there's concern as to whether new and existing technologies can truly achieve energy efficiency and maintain the performance people now expect from incandescent.

watts the buzz? The dominant technology for more than 125 years, a standard bulb uses an electrical current that heats a filament to produce light. Mary Beth Gotti, manager of GE Consumer & Industrial's Lighting & Electrical Institute in Cleveland, explains its appeal: “The color quality of an incandescent bulb has a lot of red, so it produces a warm glow and is very flattering on the skin,” she says. “It also comes in different shapes and sizes and is dimmable.” That a bulb costs as little as $1 is gravy.

The problem is that incandescent—available in halogen and parabolic aluminized reflector (PAR) lamp form—hogs energy, offering only 10 to 15 lumens per watt. “For all the energy it consumes, only 10 percent is visible light,” Gotti says. The rest is heat. And even though “the initial cost is low, it's expensive to operate.”

To date, the list of viable alternatives to incandescent is short, but its variety is rich. Of these options, compact fluorescent (CFL) is the most prominent. Strikingly different from the long tubes most people reviled, CFLs use an arc discharge through a phosphor-lined tube to generate light. According to ToolBase Services, the technical information resource of the NAHB Research Center in Upper Marlboro, Md., fluorescent lasts up to 10 times longer than incandescent. In the past, ToolBase says, this technology produced an undesirable “bluish” hue that discouraged people from using it, but “the warm tones of newer compact fluorescent lighting make it almost indistinguishable from incandescent lighting.”

Besides improved performance, CFL has a light output of 40 to 80 lumens per watt, so it's extremely efficient. ToolBase says the bulbs—which consist of a lamp, holder, and ballast—use 50 percent to 80 percent less energy than incandescent. Paul Vrabel, director of the energy-efficient products group at Sea Gull Lighting Products in Riverside, N.J., agrees, noting that with CFL, “you get long life and brighter light in a smaller package.”

The fluorescent bulbs consumers know have a spiral shape, but several other types—including pin-based T5 and T8 tubular units for architectural applications—are available. Medium-base bulbs screw into standard sockets, but Gotti says they perform more effectively in portable lamps or in fixtures that allow air to keep the bulb cool. Manufacturers are keeping pace, producing Energy Star-rated fixtures designed specifically to hold pin-based fluorescent bulbs. Such fixtures have an attached ballast (rather than one that's integrated with the bulb), so heat buildup isn't an issue.

feel the burn Despite these improvements, CFLs do have shortcomings: they're better for general illumination and less effective for lights that are switched on and off with great frequency. In fact, Energy Star recommends installing CFLs in fixtures that are used for at least 15 minutes at a time or for several hours per day.