Old-style lamps that are fast becoming a design necessity for retro bars, modern restaurants and elegant homes from New York to London are helping to save the Earth and keep people buying.
Outdated bulbs, which resembles the inefficient incandescent technology patented by Thomas Edison in 1878, could encourage people to change their bulbs more than once a decade, even as the world switches to greener lamps.
Rearranging LED chips in a strip inside the bulb Together, the bulb manufacturers found that they can satisfy the innate human desire for a warmer and more natural light, which the first generation of LED bulbs could not offer.
"People are looking for that brightness and the warm, welcoming effect seen in incandescent light bulbs," said Kristof Vermeersch, head of global product management for LED spots at Philips Lighting NV.
Changing fashions in lighting could help boost sales of LED bulbs that would otherwise have to be replaced every 10 to 15 years, because they are much more efficient than incandescent bulbs that need to be replaced several times a year.  "The real problem with LED lighting is that the bulbs last for years, so they do not have these replacement cycles where the market just keeps making money," said Tom Rowlands-Rees, analyst at Bloomberg New Energy Finance. Now the industry has found a way to make people pay more for lighting because it's great, "not because they need it," he said.
When LED filament technology was first demonstrated, by the Japanese company Ushio Inc. in 2008, it was not an immediate success. Sales began to take off in the last two years, however, as the design was improved, prices fell and the larger manufacturers of Philips and GE Lighting began to manufacture them as well.
"When the LED first appeared, it looked like weird material," said Justin Wang, executive director of AXP Technology Inc., the California company that introduced filament LEDs in the US. "But when the LED filament came out, it looked like a familiar incandescent light bulb."
Just four years ago, the filament LED market was small and focused mainly on some northern European countries. Shipments are now growing rapidly, and the market could be valued at 20 billion dollars worldwide by 2020, Wang estimates, using the shipping and pricing forecasts of LEDinside and TrendForce Corp.
Filament LEDs could also solve a problem for lawmakers who have long wanted to prohibit inefficient incandescent bulbs, over the objections of consumers who prefer the old style. Nearly a third of Britons who voted to leave the European Union in 2016 said they wanted to see the return of old bulbs that were banned by Brussels bureaucrats, according to a YouGov poll. Even Donald Trump mistakenly warned in 2012 on Twitter that energy-saving light bulbs can cause cancer due to the tiny amounts of ultraviolet rays they emit.
With better aesthetics, the filament LEDs could help accelerate the change of the 7 billion incandescent lamps still illuminating the planet. The demand for lighting is expected to increase 50 percent in the next two decades as the poorest countries gain more access to power, according to the United Nations. The switch to LEDs could offset part of that increase, preventing the release of more than 390 million metric tons of carbon dioxide per year.
It is still difficult for consumers to distinguish the difference between an incandescent bulb and an LED filament, and manufacturers like GE say they need to do more to promote the benefits of this growing market.
"LED has been a tough sell because it has to teach consumers and retailers about the technology," said Matt Sommers, manager of consumer innovation at GE Lighting. "We can not just assume that they can see it and know what it is"
– With the assistance of Chisaki Watanabe