Katherine Boehret

Picking the Brightest, Most Efficient Bulb

The light bulb used to be one of the simplest hardware-store purchases. Now a walk down the lighting aisle prompts an assortment of questions. Is it energy efficient? Will it switch on fast? Can I put it on a dimmer? What is a lumen? How long will it last? Why so pricey? Why is it a weird color?

Here’s a brief guide to some bulb basics, with help from Consumer Reports ratings, and a peek at what the future holds for the light bulb (hint: lower prices and remote control).

The Big Three Plus One

Bulbs can be divided into three main categories: incandescents, compact fluorescents (CFLs) and light-emitting diodes (LEDs). We’re most familiar with incandescents, which make use of technology from over 100 years ago. These cost the least, but emit heat and use up the most energy. An incandescent lasts an average of 1,000 hours, or 125 days when used for eight hours a day.


Lighting Science Group’s World Bulb uses less than 13 watts and will cost less than $15 a bulb.

More recently, halogen incandescent bulbs have become popular. The bulbs, which cost as little as $3 for two, look and behave like incandescents by dimming and turning on immediately, but use less energy. The Philips EcoVantage line, which became available in April, uses 28% less energy: A 72-watt bulb replaces a 100-watt, and a 43-watt bulb replaces a 60-watt. Halogen incandescents last as long as a traditional incandescent bulb.

Compact fluorescents, the spiral bulbs that became popular about five years ago, use less energy than incandescents but made a rough first impression. Compared with incandescents, compact fluorescents can appear harsher in color and most don’t turn on immediately. They’re made of glass, like incandescents, cost about $5 to $10 each and have an estimated average lifespan of 10,000 hours, or about 3½ years at eight hours a day. They contain a small amount of mercury and can be recycled at stores like Home Depot.

LEDs, which look roughly like the incandescents we’re used to, are the latest hit in energy-efficient bulbs. They’re also the most expensive, costing around $20 to $60 a bulb, though this will drop in coming months as they become more prevalent. These bulbs, which don’t contain mercury, turn on immediately, even in cold weather. Some are made of a durable plastic and many can be dimmed. Their light-emitting surfaces remain cool to the touch. The hue of light from these LED bulbs appears more like that of the traditional incandescents. They are estimated to save up to 85% more energy than standard incandescents, with a lifespan of 20,000 to 50,000 hours, or 20 to 40 years. At seven hours a day, one bulb could last an average of 17 years.

New Labeling Explained

For years, we’ve measured light bulbs by watts, which indicate how much energy a bulb uses. But bulb brightness is measured in lumens. Many of the new light bulbs’ boxes list lumens and include helpful notes about how the bulb compares with the wattage you are looking to replace. An incandescent 40-watt bulb gets replaced with a 450-lumen bulb; a 60-watt bulb with a 800-lumen bulb; a 75-watt bulb by a 1,100 lumen; and a 100 watt by a 1,600 lumen.


The Philips L Prize Bulb consumes less than 10 watts and has a lifespan of more than 25,000 hours.

More light bulbs are now packaged with a “Lighting Facts” label. Besides lumens, this may include factors like lumens per watt (bulb efficiency); watts (energy used to make the light); correlated color temperature, which indicates cool or warm color (about 2700 Kelvin replicates what we’re familiar with in a traditional incandescent); and a color-rendering index (the measurement of a light’s appearance on objects).

Best in Show

Consumer Reports recently tested several bulbs for factors like brightness, warm-up time, light distribution and actual lumens. The $10 GE Energy Smart SAF-T-GARD earned the highest overall ranking for 60-watt equivalent spiral CFL bulbs.

The $25 Philips AmbientLED 12.5W ranked best overall in the 60-watt equivalent A19 style (the typical pear-shape found in incandescent bulbs) covered bulb category.

Future Is Bright

Lighting Science Group Corp., maker of Home Depot’s EcoSmart bulbs, unveiled its sub-$15 World Bulb in December. This is a redesigned, 60-watt-replacement LED bulb that uses less power than the 13 watts of the company’s current equivalent bulb. It’ll be available in India in February and later this year in the U.S.

Lighting Science Group also has paired with Google to create the Android@Home Intelligent LED bulb, which people will be able to control using an Android smartphone, tablet or a computer. The bulb, which is expected to come out before June, will have an embedded chip and works with a gateway box that hooks into a router.

By June, Philips Lighting North America will debut its L Prize Bulb, an LED bulb that was the first to win the Department of Energy’s “L Prize,” an award for energy efficiency. Designed to replace a 60-watt incandescent, the LED bulb consumes less than 10 watts, according to Philips. In rigorous testing, the Energy Department said, the bulb had a useful lifetime of more than 25,000 hours. The bulb will likely start out at about $50.

Picking a Bulb

Light-bulb savings calculators found online, like one from National Geographic, give people a rough idea of how much they may save over time with incandescent, compact fluorescent and LED bulbs.

Write to Katherine Boehret at katherine.boehret@wsj.com

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