Thomas Edison’s incandescent lightbulb has endured for more than a century. But when their characteristic wire filaments glow, much of the electricity they draw escapes as heat — a process that, while once a technological marvel, makes them modern-day energy hogs.
Switching to more efficient lightbulbs is a “great first step” in reducing a home’s energy use, said Larry Zarker, chief executive of the Building Performance Institute. But with a plethora of options, shopping for the best replacement bulb can be confusing. So, we turned to experts for tips on finding the right fit.
The universal vote for the most climate-friendly household lighting was LED (light-emitting diode) bulbs, which consume far less electricity than their predecessors. Where an incandescent would use 60 watts, for example, an equivalent LED uses closer to about 8 watts.
“The best place to start for somebody shopping is to look for something like Energy Star labels, which have gone through some testing,” advised Nadarajah Narendran, the director of research at Rensselaer Polytechnic Institute’s Lighting Research Center. Energy Star is the Energy Department and Environmental Protection Agency program that designates products as meeting certain efficiency standards, and the blue label should be on the packaging.
A 2017 price survey from the nonprofit Consumer Federation of America (CFA) found that a house with 20 lightbulbs could save about $1,000 per decade by switching from incandescent to LEDs. And unlike some energy-efficiency improvements, Zarker emphasized, changing lightbulbs is something renters can also do to lower their utility bills.
In addition to Energy Star, the government has tried more direct measures to encourage the move away from incandescents. On President Barack Obama’s last day in office, for instance, the Energy Department issued standards that would have effectively phased out incandescent bulbs by 2020. But Donald Trump’s administration reversed that move. Now, President Biden’s administration is aiming to reinstate the measure.
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The Appliance Standards Awareness Project estimated that there are still a billion sockets in the United States using incandescent bulbs. Implementing the higher standards, it found, would result in $20 billion in savings for consumers and a reduction of 50 million metric tons of carbon dioxide emissions by 2030. That’s the equivalent of taking about 10 million cars off the road for a year.
Politics aside, the price of LEDs has dropped dramatically in recent years, and they are now available for a couple bucks per bulb or less, essentially the same the price as incandescents. And according to data that utilities submitted to the Energy Department, about 69 percent of bulbs sold in the United States (excluding California) were LED in 2020 — that’s up from about half just two years earlier.
“Ten years ago this product was not purchasable on the market, and now they’re available everywhere,” Zarker said. “It’s very exciting.”
But not all Energy Star LED lightbulbs are the same; there are other factors to consider, as well. Some of the choices are fairly intuitive. “If you have a dimmable switch, you certainly want the bulb that works with dimmable,” Zarker said. But other variables can be more complex, such as the color tones that the bulb emits.
Early iterations of efficient lights, such as compact fluorescents, developed a reputation as bright, harsh and ultimately off-putting to consumers. Because LEDs come in various shades, said Steven DenBaars, an LED expert at the University of California at Santa Barbara, customers “need to understand what color temperature they want.”
“Soft” or “warm” are the closest to traditional incandescent bulbs, he said. The package may also list the bulb color in a unit of temperature measurement known as Kelvin, and “soft” or “warm” would translate to about 2,500 to 2,700 Kelvin. The higher the numbers, the more blue the light. “Cool” white fluorescent lights, for comparison, are about 4,000 to 6,500 Kelvin.
Another metric is the color rendering index, which is a measure of how much a lightbulb affects the color of objects it shines on. Both sunlight and incandescent bulbs have a maximum CRI of 100, and serve as benchmarks for how items appear under those light sources. This is what LED makers are striving for, said DenBaars, so he suggested looking for high-CRI bulbs, which are becoming more common.
DenBaars said LEDs have improved in other ways, too. Some now come with features that shift the color and brightness of a bulb throughout the day or at preset times. There are also “filament” LED bulbs, where the diodes are arranged to look like the filaments in an incandescent bulb.
“You almost think it’s an incandescent,” DenBaars said.
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Nonetheless, there are pitfalls to watch out for even with LEDs. DenBaars said that installing efficient bulbs can sometimes lead to complacency, in which people are less attentive to turning off lights that aren’t in use. “The other problem is that people put in more lights,” he said. In either case, it can eat into the savings that LEDs offer.
Narendran highlights a lesser-known issue: overheating. When LEDs aren’t ventilated properly, he explained, the buildup of heat can cause their life span to fall far short of the 10 to 15 years often advertised. “The heat has no place to go, and that will affect the lightbulb longevity,” he said. Particularly heat-prone situations to look out for include fixtures with multiple bulbs, as well as LEDs that are installed with a closed covering.
But Narendran said moving to LEDs makes nearly universal sense, and switching from incandescent lights can pay back in lower electricity costs in a matter of months.
“The market transformation is already a done deal,” he said. “There is definitely no reason why people should not go to LEDs.”