Over its lifetime, a single CFL can save the consumer $80 or more, depending on local electric rates.
But all CFL bulbs aren't equal. Some have lower mercury content than others, and some last much longer. Unfortunately, you can't tell the best of the best by their labels - or the U.S. government Energy Star logo. Some Energy Star labelled bulbs could not be legally sold in Europe due to excessive mercury content.
An Environmental Working Group investigation has identified 7 bulb lines made by Earthmate, Litetronics, Sylvania, Feit, MaxLite and Philips that trump the rest. These bulbs, listed in our Green Lighting Guide contain a fraction of the toxic mercury allowed by Energy Star, reducing the mercury contamination from a broken bulb. All last 8-15,000 hours, dramatically longer than the Energy Star standard of 6,000 hours, and also offer high efficiency.