How Much Energy Will You Save by Turning Off Lights?
By turning off lights when they're not in use, you can conserve energy and lower your electric bill. Exactly how much energy you can save depends on the type of lightbulb.
How much energy?
All light bulbs have a watt rating printed on them. For example, a 60-watt bulb requires 0.06 kilowatts of electricity per hour.
By turning lights off, you could save 10 to 20 percent of your total household electricity usage. You don't necessarily need to turn lights completely off to save energy--use a dimmer switch.
Only about 10 to 15 percent of an incandescent lightbulb's energy consumption results in light. Because the bulbs are inexpensive to replace, the cost of turning them on and off is negligible.
Because these bulbs cost more to produce, the overall savings of turning them off for very short periods is less, but if you will be out of the room for more than five minutes it is worth it to turn the light off.
Outdoor Security Lighting
By installing watt misers, compact fluorescent lights or metal halide bulbs, you can save as much as 80 percent of your outdoor lighting energy usage.