Compact Fluorescent Lamps (CFLs) are improved curvy versions of the tube fluorescent lights.
New CFLs use a fraction of the electricity of traditional incandescents (1/4-1/5) and last a lot longer (up to 10 times more). For an average 2 hours of energy usage per day – compared to older incandescent - they pay for themselves in less than a year.
They come with the shapes and the colors of the incandescents, and many of them are dimmable; just check the package.
LED light bulbs
LED (Light Emitting Diode) light bulbs use semiconductors to convert electricity into light.
LED products such as replacements for 25 W, 40W, 60W and 75W incandescents, desk lamps, outdoor area lights, recessed downlight and undercabinet lighting are now common…
LEDs are as energy efficient (or slightly more energy efficient) as CFLs and they have a very long lifespan (qualified LEDs can last 25 times longer than traditional incandescent lights).When replacing bulbs in recessed light fixtures you should select bulbs rated for the purpose. Otherwise you risk a shorter life CFLs.
What to choose: LEDs vs. CFLs vs. Halogen lamps
Halogen lamps (the new version of older incandescents) are the least expensive of the new types of lamps, and a reasonable choice for places where lights are left on for very short periods of time (say, less than 15 or 20 minutes per day).
Compact fluorescents (CFL) and LEDs paybacks vary with their price, quality/lifespan and the average number of hours of use. Paybacks are estimated to be between 3 and 4 years for a two hours a day use.
Consider Energy-Star or other qualified light bulbs. They will last longer.