Lightbulb Buying Guide

LEDs (Light-Emitting Diode Bulbs)
LEDs instantly brighten and light color ranges from warm yellow to cool bluer white, and colors in between. Some are dimmable. LEDs use slightly less energy than CFLs, trimming your electric bill, and most are claimed to last 20,000 to 50,000 hours. That’s about 18 to 46 years when used three hours a day.

They cost more than other bulb types, although prices continue to drop. Some A-type bulbs, named for their bulbous shape and used in lamps and other general applications, do not evenly cast light in all directions, providing spotty light. And LEDs emit more blue light than other bulb types. Any light can suppress melatonin, the hormone that facilitates sleep, but research has shown that human eyes are especially sensitive to blue. 

CFLs (Compact Fluorescent Lightbulbs)
CFLs use about 75 percent less energy, last 7 to 10 times longer than the incandescents they replace, and cast light that’s warm yellow to cool blue, and colors in between.

They take time to fully brighten, especially when used outdoors in frigid temperatures. Most aren’t dimmable, and CFLs contain a small amount of mercury and should be recycled to prevent mercury from being released into the environment if the bulbs break in the trash or a landfill. Follow the clean-up tips from the Environmental Protection Agency if you break a CFL at home. Several manufacturers offer bulbs with a plastic coating, which contain the mercury and shards if the bulb breaks.

Halogen Bulbs
Halogen, a type of incandescent bulb, uses about 25 to 30 percent less energy than standard incandescents. Halogen instantly produces light, and can be used almost anywhere and with dimmers. The A-type bulbs, used as general purpose bulbs, cast light in all directions and accurately reveal the color of objects and furnishings.

They do not last much longer than standard incandescent bulbs yet cost more. Light color is typically a cooler white or blue, and while some bulbs have a color filter that improves the light, the filter reduces brightness.  

Energy Star-qualified LEDs and CFLs meet high standards for brightness, color, and energy use and the mercury content in CFLs is capped. CFLs come with a warranty of at least two years and three years or longer for LEDs. Look for Energy Star rebates before you buy, and consider these tips:

Bring Your Old Bulb With You
It’s a sure way to know that the LED or CFL fits your fixture since some are bigger or heavier than the incandescents they replace.

Read the Label
A Lighting Facts label must appear on the packages of most lightbulbs. It indicates brightness, light color, energy use, estimated energy costs, and expected life.

Learn the Lingo
• Lumens tell you how bright the bulb—think luminous—and the more lumens the brighter the bulb. You’ll want around 800 lumens for light that’s as bright as a 60-watt incandescent.

• Color Temperature indicates light color. Warm yellow light is around 2700K (the K is for Kelvin temperature). White light is about 3000K or so. Bright white light is 3500K to 4100K and bluer white light is 5000K to 6500K.

• Color Rendering Index, or CRI, isn’t always on the box and tells you how accurately colors appear under the bulb’s light, ranging from 0 to 100 (incandescent bulbs are 100). A CRI of at least 80 is generally recommended for interior lights and differences of fewer than five points are insignificant. To compare bulbs look at the CRI of bulbs with the same Kelvin (K) temperature. We test the color accuracy of lightbulbs so you’ll see the scores in our Ratings.

Dimmable
Bulbs must be dimmable if you’re using with dimmers. Most LEDs we tested are; most CFLs are not. Our Ratings indicate which bulbs are dimmable.

Works in Fully Enclosed Fixture
Some CFLs and LEDs we tested can be used in fully enclosed fixtures, according to the manufacturers, and is noted in the Ratings. This matters because if heat builds up inside the fixture it can change the bulb’s performance and shorten its life.

Works Outdoors
Many of the tested CFLs and LEDs work outdoors but cannot get wet, and need to be protected from direct contact with rain or snow. The Ratings indicate which bulbs can be used in this way, according to their manufacturers.

Works With Motion Sensor
Also known as an occupancy sensor, it automatically turn on lights when activity is detected and shut them off after activity stops indoors or a short while later outdoors. The bulb and motion sensor must be compatible to work properly. Check the website of the motion sensor manufacturer and read the bulb package to be sure.

Works With Photocell
Another way to save energy, the photocell turns off lights when daylight appears and turns them back on when it’s dark. Check the photocell manufacturer’s website and read the bulb box for compatibility information.