The ordinary incandescent light bulb remains the most popular form of home lighting because it is so affordable. But it is also very inefficient, with 95% of the electric current being converted into heat, hot light. A 20-watt compact fluorescent light (CFL) provides as much light as a 100-watt incandescent bulb and lasts about 8 times longer. Though a CFL will cost approximately 10 times more to buy than an incandescent bulb, over its average life of about 5 years it will use roughly a quarter of the power and save more than 1,400 pounds in greenhouse gases.
