Division of Energy
Residential Energy Efficiency - Lighting
More Information on CFLs
ENERGY STAR site:
Lighting accounts for only 5 percent to 10 percent of total energy use in most homes.
Types of Lighting
Incandescent lighting is very inefficient. Much of the electricity use is changed into heat instead of light, which shortens the bulb's life. These bulbs are the most common type used in residential lighting.
Compact fluorescent lighting first became available in the early 1980s. ENERGY STAR qualified CFL bulbs use about 75 percent less energy than standard incandescent bulbs and last up to 10 times longer. Over the life of one compact fluorescent bulb (about 10,000 hours), you can save about $30 or more in electricity costs over each bulb's lifetime.
Many incandescent bulbs can be replaced with compact fluorescent bulbs. However, because of their larger size, some fixtures cannot be retrofitted. Compact fluorescents have good color rendition and don't flicker or make noise. You may notice some do not light instantly and may be slow starting in cold temperatures. Special CFL bulbs can be purchased to be used in three-way fixtures. When purchasing CFL bulbs, be sure to look at the amount of lumens the light produces instead of the watts the bulbs use. The more lumens a light produces, the brighter the light.
The best use for compact fluorescents is in lights that are left burning for many hours, such as porch lights or night lights, or where the bulb is difficult to replace, such as over a stairway.
Tube fluorescent lighting has improved dramatically over the past ten years. Fluorescent tubes almost match incandescents in color rendition. Do not be satisfied with standard cool-white or warm-white tubes. Look for products with high color rendition indexes (CIR); also look for high efficiency. A standard four-foot tube can be purchased using only 32 watts instead of 40 watts. Electronic ballasts, instead of magnetic ballasts, totally eliminate hum or flicker. Some of the newest high-efficiency lamps are smaller in diameter and would require new fixtures.
Use tube fluorescents in kitchens, bathrooms, workshops, and for indirect lighting. You can buy fixtures that can be dimmed to vary the light levels.
Outdoor lighting is good insurance against vandalism and theft. Mercury vapor lights are still the most common for outdoor lighting, but they are quickly becoming obsolete because of the higher efficiency and improved color quality of high-pressure sodium and metal halide lights.
Using lighting wisely means turning off lights when not needed. Turning off incandescent or fluorescent lights will not increase usage. There are a large variety of occupancy sensors available. Other ways to control lighting are with time clocks and photovoltaic sensors.