Light Bulbs

Inside of a fire station in Livermore, California, there’s a weird-looking, pear-shaped lightbulb dangling from an electrical cord. It doesn’t look too impressive — it gives off considerably less light than a single candle on a birthday cake.

But that’s partly because this little bulb, known as the Centennial Light, has been burning almost continuously for 124 years. It stayed alive through two world wars, the first moon landing, and the rise of cell phones and the Internet. In modern life, it’s hard to imagine anything we own lasting more than a century, let alone a lightbulb.

So, the Centennial Light raises a question: if we could build a hundred-year lightbulb at the turn of the 20th century, why do modern lightbulbs only last a fraction of its lifespan?

DILLON: You have a much more complicated product at the end of the day. So there can be more failure points which might reduce the lifespan. There’s always these trade-offs with light bulbs.

For the Freakonomics Radio Network, this is The Economics of Everyday Things. I’m Zachary Crockett. Today: lightbulbs

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It’s easy to take the lightbulbs in our homes for granted. Most of us don’t even think about them until they need to be replaced. But reliable light wasn’t always easy to come by.

BROX: For so much of human history, light was just either a candle or a lamp with some kind of horn or glass cover and a flame that had to be lit. 

That’s Jane Brox. She’s the author of the 2010 book, “Brilliant: The Evolution of Artificial Light.”

BROX: The wealthy had beeswax candles which, you know, burned brightly and evenly and did not stink. The poor had their tallow which stank and would blow out and had to be constantly tended.

In these early times, most business stopped at nightfall.

BROX: Certain crafts people were not allowed to work after dark because the light was so dim that it would compromise their work. Night just shut down the world. There was a commercial pressure to extend the day.

For centuries, we tried to find ways to make flames last longer. Candles eventually gave way to oil, kerosene, and gas-powered lamps. But these solutions still came with limitations. And a new source of light emerged as a promising alternative: electricity.

BROX: In the late 18th century, early 19th century experiments around all kinds of electrical things were going on. There was the invention of the arc light — an arc of light which went between carbon. But it was too bright for a lot of applications. You couldn’t bring it indoors. So there was this great desire to find a more intimate light for indoor applications.

Throughout the 1800s, many inventors worked on early iterations of the light bulb. In the end, it was the self-taught American businessman Thomas Edison who achieved the most success.

BROX: Thomas Edison came in in 1879, and said, “You know, I see it all here.” And he sort of picked up on all the experiments that had gone before him. 

Edison’s incandescent light bulb worked by passing an electric current through a thin filament enclosed in a vacuum-sealed glass bulb. Electrical current heated the filament until it glowed. In his Menlo Park lab, Edison tested thousands of different filaments — various woods, tarred cotton, and even pomegranate peels — before settling on carbon.

He patented his light bulb in 1880 and proceeded to sell thousands of them for $1 apiece — around $30 in today’s money. Other manufacturers soon developed their own designs and mass-produced bulbs for half the cost. But Edison’s real feat was designing an electrical grid that could bring this new technology to households all over the country.

BROX: He saw that he had not only to perfect the light bulb, he had to perfect the system of distributing that light. He saw it as an urban system working through a city. 

By the late 1920s, nearly 7 in 10 American households had electricity.

BROX: When people finally got light in their farmhouses, they would turn on all the lights in the house and drive away and just look back at their house with the windows fully lit. Because that’s what they were waiting for. It became an aspiration.

That aspiration also played out abroad. In Europe, new companies were formed using General Electric’s patents, as well as competing designs from inventors like Joseph Swan.

BROX: There was lots of competition, all different companies, and lots of advertising about the attributes of one electric bulb over another.

All of this competition pushed light bulb manufacturers to create a better product. And the biggest selling point was the longevity of the bulb.

KRAJEWSKI: The usual lifespan of a light bulb was about 1,500 to 2,500 hours.

Markus Krajewski is a philosopher and historian of technology at the University of Basel in Switzerland who has written about light bulbs. He says that, while longer-lasting lightbulbs were great for consumers, they posed a problem for the companies that made them.

KRAJEWSKI: On the one hand engineers are striving for the best technological product and in that sense longevity is something you would like to reach. But for the marketing department of course it is a challenge because how would you convince the consumer that he or she should substitute a fully functioning item? If it is still burning or glowing, why should you go for another one?

Essentially, says Krajewski, light bulbs got too good. And on Christmas Eve of 1924, the CEOs of all the big light bulb companies gathered at a nice hotel in Switzerland and decided to do something about it.

KRAJEWSKI: All of them had close ties and they were communicating with each other and they realized, well, if we are competing to each other, we would ruin each other. So why do we not cooperate on a not so visible level? What happens if we would intentionally reduce the lifespan?

These companies formed an organization known as the Phoebus Cartel. And, they set out to cut the lifespan of lightbulbs in half.

KRAJEWSKI: Their goal is to produce light bulbs all over the world which stop working after 1,000 hours. That is explicitly the goal of this committee.

The tactic of intentionally limiting the usable life of a product — now known as planned obsolescence — was a novel concept at the time. The cartel positioned the change as a trade-off in achieving brighter and more efficient lightbulbs. But Krajewski says their real motive was to drive more sales.

KRAJEWSKI: The engineers in the companies received the order by their CEOs that they should radically rethink the product by implementing an intended error into the technology. “We have to alter the glue. We have to differently prepare the filament. And we have to use a contaminated element in the filament in order to let it stop working after 1000 hours.”

CROCKETT: And did this effort work?

KRAJEWSKI: Yes, definitely. In the late 1920s, you would rarely find an autonomous producer of light bulbs anymore. So everything more or less was controlled by the cartel.

The Phoebus Cartel eventually fizzled out during World War II. As it turned out, countries on the opposite side of the battlefield had trouble staying united in the boardroom. The organization’s agreement was nullified in 1940.

KRAJEWSKI: You will not find any historical evidence for the continuation of the cartel after that anymore. But that is due to the company’s archive. Afterwards, we do not have access to historical evidence anymore.

But a hundred years later, there’s no indication that the lightbulbs in our homes are a part of some grand conspiracy. In fact, according to some scientists, we’re now in the golden age of lightbulb innovation.

DILLON: Light bulbs today have much longer lifespans than they did before. It’s rare that we have an evolution in a technology that offers such an order of magnitude benefit in terms of all of the upsides of some of the more modern lighting products.

That’s coming up.

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Today, you’re not likely to find many incandescent light bulbs on store shelves. In the U.S., a Department of Energy directive effectively banned them from being sold, starting in late 2023. These days, it’s all about the light-emitting-diode, or LED. And that’s partly thanks to the efforts of people like Heather Dillon.

DILLON: I’m a mechanical engineering professor at the University of Washington in Tacoma. Broadly, I work in the areas of energy efficiency and renewable energy. I’ve been doing research on lighting in particular for about 20 years. 

In the decades after the Phoebus cartel, incandescent bulbs continued to be the prevailing lighting option. But scientists began to think about whether the millions of light bulbs in people’s homes could be more efficient.

DILLON: One of the challenges with traditional incandescent products is that they generated a lot of heat when they converted the electricity to light. If you had a lamp with a 100 watt bulb in it, you could hold your hand over it and definitely it would be quite warm. That’s basically the core of what made an incandescent light bulb inefficient — because of all that heat loss.

In the midst of an energy crisis in the 1970s, a new type of bulb, called the compact fluorescent lamp, or CFL, was developed. You might remember them as those squiggly, spiral-shaped light bulbs that had a harsh hue.

DILLON: They offered a lot of energy efficiency benefits, but people didn’t really like the light. I think that there was a lot of moments where people would talk about sort of the tragic quality of fluorescent lighting — you know, that icky green color. And so the products weren’t particularly popular. 

But there was an emerging alternative called the LED.

DILLON: You can think about an LED product as a little more like your phone than an incandescent. LED products actually have little chips and wires and things that basically allow them to control light temperature and light quality. And do so in a way that looks like a traditional light bulb to you and I.

LED lights had been around since the 1960s, but mostly as small single-color bulbs used in electronics, like calculators, digital watches, and TVs. For decades, harnessing this technology in light bulb form was prohibitively expensive. But in 2000, a small group of scientists and engineers — including Dillon, at the very beginning of her career — began to rethink the potential of LEDs. With funding from the Department of Energy, they worked closely with manufacturers to create a better lightbulb.

DILLON: Picture 10 or 15 engineers sitting in a dreary conference room, that is lit by terrible fluorescent lighting. And they’re sitting there with a whiteboard, and they’re charting, “How do we make sure that LEDs can be adopted and get the cost down as quickly as possible while not compromising any of the important things about lighting?” They were getting early products, they were testing them in their own homes, they were taking them apart. There was one study we did at one point where we basically put lighting products in a blender so that we could understand what types of harmful materials might be in there. Knowing that there’s this group of people who are carefully monitoring all of these lighting products, I think the manufacturers then in turn sort of built the product better when they maybe didn’t have to.

This group was able to steer lightbulb manufacturers toward a longer-lasting, more efficient product, and bring the price down to compete with incandescent bulbs. Between 2015 and 2020, the percentage of American households using LEDs for most, or all, of their indoor lighting jumped from 4 percent to nearly 50 percent. A Goldman Sachs analyst called the rapid adoption of LEDs one of the fastest technology shifts in human history.

DILLON: One of the benchmarks that they were looking for in the early days was to get the price under $10, and now you can buy one for much closer to $3.

That’s still a bit more expensive than incandescent bulbs were. But LEDs are far more efficient.

DILLON: In lighting, we like to talk about lumens per watt. And lumens are the light that you could measure. And then the watt is how much electricity or how much energy you’re actually putting into the system. 

A standard incandescent bulb used to require 60, or even 100, watts. Today, an equivalent LED bulb uses less than 10 watts.

DILLON: These products are a really big upgrade in terms of your power bill. So the Department of Energy has estimated that an average consumer will save over $200 per year on the cost of lighting in their home if they were to upgrade to LED products. And so 200 bucks a year, I mean that’s not trivial for a lot of families.

They aren’t just more energy efficient — they also last a lot longer than incandescent bulbs. Manufacturers come up with estimated lifespans for LEDs by running them in temperature controlled rooms for long periods of time. They use mathematical calculations to project the number of hours a product might last before failing.

DILLON: They try to do some modeling and things like that. I think the truth is that it can be really hard for them to predict.

The Department of Energy reports that LED lightbulbs can last up to 30 times longer than incandescent bulbs. And some products report a lifespan of 50,000 hours — around 17 years of use at 8 hours per day. But because LED lightbulbs have so many electronic components inside of them, it’s not unlikely that some other part of the bulb will fail before the light itself.

DILLON: The LED light engine itself tends to last for a really, long time. But some of the other components — the chip components, little circuit boards — if something is soldered together poorly, it could have a failure. There’s still lots of ways they can fail, even if the underlying technology can last for a really long time.

Markus Krajewski, the technology historian, is skeptical of the industry’s reported bulb lifespans.

KRAJEWSKI: If the lifespan of an LED light comes with 50,000 hours, you have to be a bookkeeper, and a very meticulous one, to control the lifespan of an LED. So, that is pure fiction. That’s all I want to say.

Even so, looking back at the era of lightbulb cartels and planned obsolescence, it’s hard to deny that today’s products are better. And at some point, even the 124-year-old Centennial Light in that fire station in California will probably be phased out for a more efficient and practical LED. While it’s technically still glowing, the bulb now produces less than 1 percent of its original brightness.

KRAJEWSKI: The reason why it is emitting light is, it is on such a low voltage. I would even doubt that you can consider it as a working light bulb, because it is radiating heat maybe, but much less light.

For The Economics of Everyday Things, I’m Zachary Crockett.

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This episode was produced by me and Sarah Lilley, and mixed by Jeremy Johnston. We had help from Daniel Moritz-Rabson. And thanks to John Hunter for suggesting this topic. For more on illumination, and planned obsolescence, check out the recent episode of Freakonomics Radio called “Why Do Candles Still Exist?” You can find it wherever you get your podcasts. We’ll catch you next week.

BROX: I still love a flame. You know, a flame has a life to it. You could sit there and meditate on a flame for a long time. You can’t really do that with an electric bulb.