Efficient Home Lighting Choices: Page 3 of 4

Intermediate

Inside this Article

Lighting Examples
Informational lightbulb packaging
Lighting packaging usually gives you all the data you need.
DOE lighting facts
Some products will bear the U.S. DOE’s Lighting Facts label, which helps identify a bulb’s characteristics, such as light output, efficacy, and color rendering.
Compact Fluorescent examples
Incandescent examples
LED examples
LED bulbs in stores.
LED lighting for many applications is now available at your local hardware store.
Beam angle matching
Matching beam angle to the lighting task is important—wide for area and ambient lighting, or narrow for task lighting. Until recently, LEDs were hampered by narrow beam angles, but that is changing.
Lighting Examples
Informational lightbulb packaging
DOE lighting facts
Compact Fluorescent examples
Incandescent examples
LED examples
LED bulbs in stores.
Beam angle matching

Although they were once the only affordable energy-efficient lighting option, they come with caveats. CFLs do a reasonable job of rendering many colors, but they don’t render all colors well—and that’s easily noticed by people with particularly sensitive vision. Others have concerns about how to avoid mercury exposure if they get broken, and how to safely dispose of them. (Note that most analyses have found this to be secondary to their other environmental benefits, since their energy savings results in mitigating much greater mercury emissions from fossil-fuel power plants. See HP153, “CFLs & Mercury.”)

CFLs are also not usually dimmable, and can overheat in enclosed fixtures. This helps to explain why they are broadly used in some homes but rarely in all of a home’s light fixtures.

CFLs typically operate at about 50 to 70 lumens per watt and will run for about 8,000 to 18,000 hours before burning out. While they offer a low-cost way to save on lighting energy, they are increasingly being displaced by their better-performing cousins—LEDs.

Light-emitting diodes (LEDs) are quickly gaining ground as the most energy-efficient lighting technology. Although early LED models were bulky, expensive, and not very bright, those products have yielded to a new generation of quality products that use 10% to 30% less energy than CFLs, are easier to dim, and last far longer.

LEDs once operated in a similar efficiency range to CFLs, but can now achieve 85 lumens per watt across a wide range of light output levels, and best-in-class LED designs are headed to 100 lumens per watt—and beyond.

You can find comparisons of more than 17,000 LED lighting products, including information on lumens, watts, efficacy, color rendering index, and correlated color temperature, at lightingfacts.com.

The difference in color quality among incandescents, CFLs, and LEDs can be seen in the spectral distributions graph, which show how much of the light from each source falls within each wavelength of the visible spectrum, and compares that to the human eye’s sensitivity to each of those wavelengths (dotted curve). Note that incandescents (halogens) and LEDs both offer a continuous spectrum of colors, but incandescents tend to be dominant in the reds and fairly limited at the blue end of the spectrum. LEDs are often the reverse. CFLs, on the other hand, only emit light within certain portions of the visible spectrum, so can disappoint some users who are particularly sensitive to subtle color differences.

Matching Bulb to Application

Most home applications call for omnidirectional sources of light. “General service” bulbs work well in many kinds of table and floor lamps, enclosed globes, pendant fixtures, and other types of narrow light fixtures that mount close to the ceiling or wall. LEDs are a great option, but make sure they are truly omnidirectional. Many older models that have a snow-cone appearance shine most of their light upward.

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