What’s watt? How to read those labels

Light-emitting diode (LED) bulbs and compact fluorescent (CFL) bulbs last longer and use less energy than traditional incandescent bulbs, but making the switch can be confusing. Most of the confusion stems from the fact that the term “watt” became synonymous with the brightness of the bulb for traditional incandescent bulbs.

You don’t have to be a rocket scientist to decipher the packaging on the new bulbs, but understanding the terminology will help you achieve the look you want in your home. The Federal Trade Commission worked with lighting manufacturers to create a Lighting Facts label to help consumers shift to the more energy-efficient bulbs.

Consider these three things when purchasing bulbs:

Watts (“Energy Used” on the Lighting Facts label) tells you how much energy it takes per hour for the bulb to work. LEDs and CFLs use fewer watts to generate the same amount of light as an incandescent bulb.

Lumens (“Brightness” on the Lighting Facts label) indicates the brightness of the light. (Geek fact: One lumen equals the amount of light generated by one candle.) If you want the same amount of light as a traditional 60-watt incandescent bulb, look for a bulb with at least 800 lumens. A 40-watt incandescent bulb has approximately 450 lumens.

Hue (“Light Appearance” on the Lighting Facts label) refers to the color of the light and is measured in degrees Kelvin. Energy Star uses this scale to describe light color:

Warm white/soft white— 2700-3000K

Cool white/neutral— 3500-4100K

Natural/daylight—50006500K

To illustrate the savings realized by switching from incandescent to more energy-efficient bulbs, count the number of light bulbs in your home and multiply that number by $68.75 for CFL or $72.75 for LED (the total savings for 25,000 hours of light).

Switching 30 bulbs to LEDs can save more than $2,000 during 25,000 hours of use. A household with 50 bulbs can save more than $3,600 by switching.

— Nathania Sawyer