First, CFLs use significantly less energy -- 75 percent less energy than incandescent light bulbs. That means CFLs require less wattage to produce an equivalent amount of light. For example, you could use a 20-watt CFL and enjoy the same amount of light as a 75-watt incandescent. If every home in America made one such swap, enough energy would be saved in one year to light more than 3 million homes [source: ENERGY STAR].
Of course, if you're using less energy, your energy costs are going to go down. Replacing a standard 60-watt bulb with a 13-watt CFL can save a single household $30 in energy costs over the life of the bulb [source: General Electric]. Even with the higher price tag of CFLs -- you'll pay $2 to $4 for a CFL versus 30 to 40 cents for a typical incandescent bulb -- they still save you money. That's because CFLs last a long time. In some tests, they burned brightly for 10,000 hours, whereas standard bulbs burned for just 800 to 1,500 hours [source: Johnson].
The environment comes out ahead, too. A good deal of electricity coming from coal-fired power plants gets directed to the lamps and light fixtures inside your house. If you're saving energy by using CFLs, then you're pulling less electricity from the power grid. This reduces the amount of coal that must be burned, which reduces emissions of greenhouse gases. In a single year, the use of CFLs over incandescent bulbs removes as much greenhouse gas pollution as taking 2 million cars off the road [source: ENERGY STAR].