Wal-Mart set an ambitious goal of selling 100 million compact fluorescent lights (CFLs) in the United States this year. The Bentonville, Arkansas-based retailing giant touted the energy-saving and financial benefits of switching from power-hungry incandescent bulbs to more-efficient CFLs.

With the recent announcement that it is selling its own private-label CFLs in more than 3,000 U.S. stores, Wal-Mart is hoping that the so-called “unbeatable price” of its bulbs will spur sales.

The 9-, 13-, 18-, and 23-watt Great Value–brand spiral CFLs, which you can use in a variety of indoor and outdoor applications, come in four-packs that cost $7.58. For our October 2007 report on CFLs, “New twists in savings,” we paid about $8 or $9 per four-pack of spiral bulbs.

We haven’t yet tested the Wal-Mart CFLs, but the company claims they are Energy Star qualified. This means they meet the government’s standards for start-up and warm-up times, brightness, color, bulb life, and energy use; they also cannot hum or buzz. Our experts recommend that you use only Energy Star bulbs for those locations where you’re considering installing CFLs.

It’s worth noting that CFLs contain a small amount of mercury, so it’s important to properly handle and dispose of them. Wal-Mart CFLs, says a company spokesperson, do not exceed 5 milligrams per bulb and comply with the European Restriction on Hazardous Substance standards for mercury and heavy-metal content.—Kimberly Janeway

Essential information: Find out how the major brands of CFLs compare to one another. (This information is available to subscribers.)