You can save money and energy by replacing your incandescent light bulbs with compact fluorescent lights (CFLs). Compared with incandescents, CFLs use roughly one-third the energy to produce the same amount of light, and last up to twelve times longer. Of the energy consumed by an incandescent bulb, only about 10 percent is used to generate light; the remainder becomes heat.
Lighting consumes about one-quarter of the electricity used in the U.S. and accounts for more than $37 billion in annual energy costs. For every high-use incandescent bulb you replace with a CFL, you'll save an average of $50 in energy and bulb replacement costs over the life of each CFL.
If every U.S. household replaced just one frequently used incandescent bulb with a CFL, more than 6 billion kWh of electricity could be conserved annually-enough to light every home in New York City for an entire year.
Sources:
Energy Star
Department of Energy