Lighting Standards
Traditional incandescent light bulbs have not changed in more than a century.
They are one of the most inefficient products in most homes. As part of the Energy Independence and Security Act of 2007 (EISA 2007), traditional light bulbs must be 25 percent more energy efficient while maintaining the brightness and quality. These Federal standards are intended to reduce energy usage, greenhouse gas emissions and dependency on foreign sources of energy.
The new lighting standards will be phased in starting with the 100-watt bulb the first year, followed by 75-, 60- and 40-watt bulbs over the next two years. Compliant bulbs will operate at lower wattages for similar light output, or brightness, which is measured in lumens, see link here.