Many people don't consider their light bulbs a major expense. But if every American homeowner installed one energy-efficient light bulb in an existing light fixture, the nation would save $600 million in energy costs and prevent carbon emissions equal to 800,000 cars each year.

The Consortium for Energy Efficiency, a Boston-based non-profit, created a plan to cut lighting energy in half by 2012. The Consortium, along with the American Lighting Association, encourages the public to buy fixtures with the Energy Star, a designation created by the Environmental Protection Agency and the U.S. Department of Energy to note products that meet strict environmental standards. Other energy-saving suggestions include using dimmer switches.

Dimmer switches result in less wattage being used, extending the life of bulbs while also reducing electricity bills. Dimmers also prove easy on the eye. Certified Lighting Consultant (CLC) Monty Gilbertson of Lighting Design by Wettsteins in LaCrosse, Wis., says, "Dimmers allow for greater flexibility in lighting product selection and allow multiple uses of a room."

If people are gathering for a dinner party, hosts can turn the lights to their brightest setting. During dinner, the host can set an elegant mood simply by lowering the light. "It's nice to be able to bring the lights to full strength again with the flip of a switch," says Karen Engle, CLC, of Zanger Associates, Inc. in Eldersburg, Md.

The three main types of lighting used in American homes are incandescent, magnetic low-voltage and electronic low-voltage lights, all of which can be easily dimmed.

Several types of dimmers exist. Wall box dimmers control one or two lights, while scene lighting dimmers allow home owners to control several lights from one panel. Whole-house systems control every light in the home from a single panel. Occupancy sensors turn off and on when they sense motion.