Buzz
There’s a reason why your parents used to remind you to switch off the lights when leaving a room. According to the U.S. Department of Energy, lighting accounts for up to 5 percent of an average American household’s total energy use. Living rooms are bathed in bright lights. Dining areas and dens are filled with accent lighting. Motion sensors, hallway lights, bathroom vanity lights, lamps—we love keeping our spaces well-lit.
Luckily, energy-efficient lighting options have mostly replaced traditional incandescent bulbs, which once consumed a significant amount of power. Those bulbs worked by heating a tungsten filament to produce light. However, nearly 90 percent of the energy they used was turned into heat, wasting energy and driving up utility costs. Today’s bulbs shine brightly without that wasted energy. That’s the good part. The downside? The range of bulb types can be overwhelming. If you've ever found yourself confused in the lighting section at the hardware store, here’s a simple guide to understand what these terms mean.
Halogen Incandescent:
These are incandescent bulbs with a halogen gas-filled capsule surrounding the filament, boosting energy efficiency. Although they cost less to run than regular incandescent bulbs—using 25 to 30 percent less energy—they don’t offer as significant savings as other alternatives. The upside? They reach full brightness instantly. Other types may need time to warm up.
Compact Fluorescent Lamp (CFL):
When you spot a coiled bulb, it’s likely a CFL, a smaller version of the fluorescent lights typically found in commercial buildings. Unlike incandescent bulbs, which pass electricity through a filament, CFLs send current through a tube filled with argon and mercury vapor. This creates ultraviolet light that triggers phosphor inside the tube to glow. It uses just one-third of the energy of a halogen incandescent bulb. The downside? They can take a little time to warm up, especially outdoors. Plus, they contain mercury, posing a health risk if broken. (See the "mercury" entry below.)
Light Emitting Diode (LED):
This bulb type employs a semiconductor to transform electricity into light. Energy-efficient and long-lasting, LEDs typically outlive halogen incandescent bulbs by eight to 25 times and CFLs by four to eight times—lasting anywhere from 18 to 46 years. Though they may cost more initially, the price is balanced by their long lifespan. Many LEDs also work with dimming switches, a feature most CFLs lack, so if dimming is important, LED is the way to go.
Energy Star:
A bulb carrying the Energy Star label has been reviewed by an independent party to ensure its energy-saving claims are reliable, and it generally comes with a longer warranty than non-Endorsed bulbs.
But what about the "nutritional label" style information that you often see on light bulb packaging? Let’s examine it more closely.
Brightness:
You’ve likely already guessed that brightness refers to how much light a bulb emits. This is measured in lumens, usually rounded to the nearest five. (For example, a bulb won’t be exactly 822 lumens—it’ll be listed as 820.) The higher the number, the brighter the bulb. If you’re accustomed to judging bulbs by wattage, a bulb with 800 lumens is about the same as a 60-watt incandescent bulb. A 1100 lumen bulb is comparable to a 75-watt bulb.
Estimated Energy Cost:
This is an approximate calculation of the cost for an average household to run the bulb. What is considered average? The calculation is based on the bulb’s wattage with three hours of daily use, assuming a cost of 11 cents per kilowatt. Your actual cost may vary depending on how much you use the bulb or if your energy provider charges a different rate.
Life:
This refers to how long the bulb is expected to last, based on the same usage assumptions used for the energy cost calculation, and is rounded to the nearest tenth of a year.
Light Appearance:
This refers to the bulb's color temperature, measured in Kelvin, a scale that gauges the color of light. The spectrum ranges from 2600 K (warm, yellow light) to 6600 K (cool, blue light). Bright white typically falls around 3500 K. For most interior rooms, it's best to stay below 3000 K.
Energy Used:
This indicates the energy consumption of the bulb, measured in watts. The lower the wattage, the cheaper it is to run. This is where energy savings come into play, as a 10-watt LED can produce as much light as a 60-watt incandescent bulb.
Color Rendering Index (CRI):
Though not always listed on packaging, if it is, the CRI measures how true-to-life colors appear under the bulb's light, rated on a scale from 0 to 100. Halogen incandescent bulbs generally score highly, while CFLs and LEDs are less accurate, though they can still serve the purpose. If you'll be using the bulb in spaces like bathrooms, aim for a high CRI, as lower CRI values may distort skin tones.
Mercury:
Some CFL bulb packaging might include a warning about mercury. This isn't a problem as long as the bulb stays intact, but if it breaks, it could release harmful mercury vapor, posing a slight risk of mercury poisoning. To minimize this risk, avoid using CFL bulbs in children's rooms where they might be knocked over. If a bulb breaks, it should be cleaned up carefully according to Environmental Protection Agency guidelines—use tape to pick up the pieces, not a vacuum—and properly disposed of. Recycle old bulbs.
