In the New Yorker, J B Mackinnon (beloved of TreeHugger for the Hundred Mile Diet) writes about another of our obsessions, the LED bulb. He describes how all the lightbulb manufacturers got together in 1924 and essentially formed a cartel, Phoebus, to ensure that a conventional bulb should last about a thousand hours, so that there would always be a market for them.
Phoebus members rationalized the shorter design life as an effort to establish a quality standard of brighter and more energy-efficient bulbs. But Markus Krajewski, a media-studies professor at the University of Basel, in Switzerland, who has researched Phoebus’s records, told me that the only significant technical innovation in the new bulbs was the precipitous drop in operating life. “It was the explicit aim of the cartel to reduce the life span of the lamps in order to increase sales,” he said. “Economics, not physics.”
Now we have LED bulbs that are commonly rated at 25,000 hours. Given how most people use bulbs, that’s about 22 years. This raises the spectre of what the industry calls “socket saturation” or what TreeHugger might call Peak LED, where everybody has all the bulbs they need and since they never have to be replaced, sales decline precipitously. Some are responding to this by making cheaper bulbs with a shorter life designed right in; others are taking a different approach. MacKinnon writes about Design Professor Tim Cooper, who believes products should be built to last:
The economic model to aim for, Cooper said, is founded on people buying fewer, but better, products, and paying more across those products’ lifetimes. The manufacture of quality goods would employ more people, and the goods would sell at higher prices.
This appears to be the thinking at Cree, the LED pioneer in Durham, North Carolina. They have just revamped their entire line of consumer bulbs and have gone seriously for quality over price. According to the press release,
The new bulb portfolio consists of 25 new products, offering better light quality, better dimming, better lifetime, better warranty and better pricing to deliver on the true promise of LED technology to make lighting better than it was before. Notable features in the new bulbs include superior lifetimes, with most projected to last 22+ years and some up to 32 years. Color rendition is improved, with smoother, quieter dimming to levels as low as 1 percent.
This is really the critical thing, making bulbs that people perceive to be as good as the good old incandescent bulbs they were used to. Cree’s VP of marketing – consumer products, Al Safarikas, explained how they have studied people in rooms (as shown in the video above) and what they did to develop a bulb where people just liked the light better. They tested different color temperatures, lighting levels and other tweaks to figure out what looked best to the general consumer who really doesn't have words to describe it. The lessons were clear: people like "better" light, a higher Colour Rendition Index (CRI). But lots of LED bulbs have high CRIs and they don’t all look the same, or as good.
Al Safarikas tried to make the case that light quality is actually more important than light quantity. “People believe that they need more light to see better, but really what they need is better light, and you see it in the videos, people saying that they can see better”- when the actual light level is the same. I asked what he actually meant by better:
I mean a higher CRI. I am mean a better adherence to keeping the light on the Planckian black body line. What you see with a lot of inexpensive LED bulbs is that they seem weird, the light seems a little alien, you say “that doesn’t look right” and what it really means is that it is off the Planckian black body line. If you want to build a bulb of higher quality you want to make sure it stays on the black body line. You want to make sure that the color rendering is very good. Non-technical people simply look at it and say “things look better. I see better. I perceive better.” Older technologies and cheap LEDs will often stray from that.
In an incandescent bulb, which has a CRI of 100, the light has a smooth full spectrum that is equivalent to heating up a piece of metal to the temperatures shown on that line. LEDS, however, do not work by heating up a piece of metal; instead most bulbs work by using UV light which causes phosphors to fluoresce. This results in a spiky spectrum; the trick is to mix the phosphors to make it most pleasing to the eye. The CRI is a rating of how close it gets to incandescent, to that line on the graph. That’s what makes the light “better”. (Read a better explanation here)
Most people like a “warm” bulb, more like an incandescent bulb, but this is a matter of preference. And as the baby boomers get older, their lighting needs change and evolve. Safarikas again made the case that as people age, they need quality over quantity; I was in fact a bit dubious of this, but the Lighting Research Center notes changes as the eyes age:
- Reduced contrast and color saturation - The crystalline lens becomes less clear and, as a result, begins to scatter more light as one ages. This scattered light reduces the contrast of the retinal image. This effect also adds a "luminous veil" over colored images on the retina, thus reducing their vividness (saturation). Reds begin to look like pinks, for example.
- Reduced ability to discriminate blue colors - The older eye loses some sensitivity to short wavelengths ("blue light") due to progressive yellowing of the crystalline lens.
This might well explain the lighting wars I have with my wife around the dining room table; I am older than she is, and not only prefer the light brighter, but also bluer. She can’t stand cool white bulbs but I am perfectly happy with them. And it is clearly not just a function of light intensity, but also quality and color balance.
Cree has done their best to make these new bulbs look as ordinary as possible; there are no silly cooling fins anymore, it looks like a plain old bulb with a plain old traditional Edison base. But as noted earlier, the light bulb is no longer a consumable that needs to be easily screwed in and out and replaced; it is a durable now, lasting as long as the fixture. But Cree appears to be trying to make the transition as easy as possible for people; it looks unthreatening, will fit in any old fixture (they are even making a 3 way bulb for really old fixtures) and and comes with a ten year warranty. I worry about making it so ordinary, that people will still think of them as consumables and buy on the basis of price. I worry also that they rate the bulbs in terms of "60 Watt replacement" with the light output in lumens being listed on the box as less important information; it's time to wean ourselves off that old number and talk lumens. But again, they are trying to keep consumers comfortable with the product.
It is also unlikely that many people will be using their LEDs for 22 years as the technology keeps changing. It’s likely that in a few years, all our bulbs will be RGB and adjustable like the Philips Hue; they will cease to be separate bulbs and will in fact be part of the fixture or even built into the fabric of our homes; they will all be smart and interconnected and talking to Alexa or Siri or your Roomba.
The way we think about lighting is going to radically change in the next few years, but right now the big change is to think about quality rather than price, because we might be looking them for a while, and these really are better bulbs.