Early adopters of LED lighting will remember 50,000 hour or even 100,000 hour lifetime ratings printed on the box. But during a recent trip to the hardware store the longest advertised lifetime I found was 25,000 hours. Others claimed only 7,500 or 15,000 hours. And yes, these are brand-name bulbs from Cree and GE.
So, what happened to those 100,000 hour residential LED bulbs? Were the initial estimates just over-optimistic? Was it all marketing hype? Or, did we not know enough about LED aging to predict the true useful life of a bulb?
I put these questions to the test. Join me after the break for some background on the light bulb cartel from the days of incandescent bulbs (not a joke, a cartel controlled the life of your bulbs), and for the destruction of some modern LED bulbs to see why the lifetimes are clocking in a lot lower than the original wave of LED replacements.
Ghosts of Light Bulb Cartels Past
Any discussion of light bulb lifetime would be incomplete without mention of the Phoebus cartel, an international organization formed in 1924 by the world’s leading light bulb manufacturers to manipulate the bulb market. As discussed by Markus Krajewski in “The Great Lightbulb Conspiracy”, the cartel assigned territories to member companies, limited production, and dictated a shortened 1,000 hour bulb life. Previous bulbs had burned for a much longer 1,500 – 2,500 hours. Purportedly imposed to increase quality, efficiency, and light output, the new 1,000 hour limit also resulted in many more bulb sales. Archived documents show that significant research was expended to devise bulbs that lasted their 1,000 appointed hours and no more. It wasn’t only household lighting that took a hit: flashlight bulbs originally lasting for three sets of batteries were reduced to two, with a proposal to limit their lifetime to a single set. Again, brightness increases were touted as the reason. However, that last step, halving bulb lifetime, would increase brightness only between 11%-16%, while doubling sales. This was about selling more bulbs and making more money.
The cartel enforced production quotas and bulb lifetimes with a system of monetary fines, backed by the power of GE’s patent portfolio. Bulbs from each producer were tested, and penalties imposed for bulbs lasting significantly shorter or longer than 1,000 hours. Phoebus continued to exert influence on the market until World War II ended its reign. The cartel is often cited as one of the first instances of planned obsolescence: designing products with an artificially shortened lifespan. A 2010 documentary, “The Light Bulb Conspiracy,” explores the history of the cartel along with some more recent instances of planned obsolescence. I wonder what the conspirators would have thought of bulbs that supposedly last 100,000 hours? Or even 7,500?
Tucked into a lower shelf in the lighting isle at the hardware store, a few lonely incandescent bulbs waited for some Luddite consumer. Picking up a box, I read the rated lifetime: 1,000 hours.
Measuring Lifetime of a Bulb
What exactly does the box mean with this 1,000 hour lifetime? This is the bulb’s Average Rated Life (ARL) — it’s the length of time for 50% of an initial sample of bulbs to fail (abbreviated B50). What “failure” means depends on the type of bulb; we’ll explore this in more depth later on. The definition of B50 reveals a common misinterpretation, namely that a bulb will last for its rated lifetime. In reality, only half of them last that long, although this rating doesn’t tell you anything about the distribution of failures around the median lifetime.
Manufacturers use these ARL values to forecast how many years a bulb will last based on using the bulb a specified number of hours per day (typically 3). LED bulbs suffer less wear-out through power cycling than incandescents, so the conversion is just a division: years of service = ARL/(3*365). For example, half of a set of 100,000-hour bulbs would still be in service after 91 years according to this calculation. But this simple metric doesn’t tell the whole story. LED bulb failure mechanisms are complex and fundamentally different from the well-known incandescents. To understand more, we need to shed some light on the inner workings of a bulb.
Before leaving the store, I threw a few bulbs in my cart so I could see firsthand what was inside.
What’s In a Bulb? Let’s Tear Some Apart!
There’s more to an LED bulb than just the LEDs. Outlets in our homes are actually fairly dirty sources of AC power. LEDs want clean, constant-current DC sources, so circuits inside the bulbs must rectify and filter the incoming AC, then limit current to the LED packages. To see how this is done, I dissected three different A19 style bulbs: one each from the GE “Basic” and “Classic” lines (7,500 and 15,000 hours), and a Cree model offering a 25,000 hour life.
GE Basic A19 Bulb (7,500 Hours Advertised)
This GE bulb has a plastic dome covering a circular aluminum PCB which carries eight LED packages and the driver electronics. The driver consists of an MB10F bridge rectifier, an electrolytic capacitor rated for 105 °C, and an SM2082D linear constant-current driver. There are three resistors on the PCB: one bleeds charge from the capacitor when the bulb is off, and two others set the SM2082D current to 54 mA. In fact, the circuit looks like it was taken directly from the SM2082D datasheet.
Seven of the 3.5 x 2.8 mm LED packages show around 18 V of forward drop when driven with 50 mA, indicating that they contain six LED dice in series. One LED on the board shows a drop of 9 V, so it has only three LED chips. All the LEDs, totaling 45 dice, are wired in series to drop approximately 135V.
GE Classic A19 Bulb (15,000 Hours Advertised)
When they say classic, they mean it. This bulb is in a glass envelope just like incandescents, and like those old bulbs, the glass is easily removed with a ball-peen hammer. In place of the tungsten filament is an aluminum PCB folded into a squat obelisk. Sixteen 3.5 x 2.8 mm LED packages are connected in series on the board, with each one showing a forward voltage of around 9 V at 50 mA. So, this version has 48 LED chips vs 45 for the Basic bulb, except they’re in twice as many packages – this is good for keeping the LEDs cool.
Another difference with this longer-lived bulb is that the driver electronics are not thermally coupled to the LEDs; they are hidden on a separate PCB in the screw base. This keeps the rest of the components from heating with the LEDs. On the driver PCB is a bridge rectifier, an electrolytic capacitor again rated for 105°C, and an SOIC-8 IC. Interestingly, this bulb also contains a metal-oxide varistor for transient suppression. Although I couldn’t determine what the house-marked (“BYSACT”) driver IC was, the lack of any inductive components on the PCB indicates this is another linear supply.
Cree A19 Bulb (25,000 Hours Advertised)
The Cree bulb has a diffused plastic dome like the GE Basic model. Inside, a larger aluminum PCB holds (16) 3.5 x 2.8 mm LED packages. Each LEDs drops around 8.5 V at 50 mA, so they contain 3 chips; like the GE Classic bulb, this one uses 48 total LED dice. The LEDs are wired as eight sections of two paralleled LEDs, so the total drop is around 68 V. The LED PCB is coupled to a thick aluminum heat sink with silicone thermal compound.
As with the GE Classic bulb, the power supply electronics are on a separate PCB, thermally decoupled from the LEDs. The driver IC is an SOT23-5 package inscrutably marked with “SaAOC”, but the presence of a transformer and stout Schottky diode reveals that this is a switch-mode power supply. The filter capacitor on the switcher output is an aluminum electrolytic rated for 130 °C.
It’s not much to go on, but what conclusions can we draw from the design of these three bulbs? It helps to consider how they typically fail, and what factors affect their lifetime.
LEDs “Outlast” Other Components
Since the LED bulbs contain a number of parts, it’s natural to ask which ones might be responsible for failures. The US Department of Energy (DoE)’s solid-state lighting program supports research and development of LED technologies, and their website contains volumes of data on LED lighting systems. Their Lifetime and Reliability Fact Sheet contains data on the failure rate of 5,400 outdoor lamps over 34 million hours of operation. Interestingly, the LEDs themselves account for only 10% of the failures; driver circuitry, on the other hand, was responsible almost 60% of the time. The remainder of failures were due to housing problems, which may not be as applicable for bulbs in indoor use. This data shows that at least for catastrophic failures (where the lamp ceases to emit light), extending lifetime means improving the power supplies.
Locate the Weakest Link: Component Lifetime
The lifetime of a bulb (or power supply) can be no longer than the lifetime of any of its components. Among the components found inside the bulbs, two stand out as life-limiters: the semiconductors and the electrolytic capacitors. Both of these components suffer from a failure rate that is a strong function of temperature. The typical model for this effect, based on the Arrhenius equation, predicts a doubling of lifetime for each 10 degree Celsius decrease in temperature, at least over a limited range.
The two longer-lived bulbs use twice as many packages to carry approximately the same number of LED dice as the GE Basic lamp, decreasing thermal resistance to their respective heatsinks, and presumably reducing their temperature. These bulbs also both mount the failure-prone driver electronics on separate PCBs from the LEDs to keep them cool. Finally, the 25,000-hour Cree bulb uses an electrolytic capacitor rated for 130 °C as opposed to the 105 °C caps in the other two. For similar operating temperatures, this could multiply the expected life of the capacitor by a factor of five. Each of these measures probably contributes to delaying catastrophic failure of the bulb, resulting in the longer rated lifetimes.
But when it comes to the LEDs themselves, there is more to lifetime estimates than predicting catastrophic failure.
Just Fade Away
Like the soldiers in Douglas MacArthur’s famous line, old LEDs don’t die, they just fade away. We all know what an incandescent lamp failure looks like: one second it’s burning bright; the next, it’s not (and every once-in-a-while, you hear a pop followed by a faint jingling as the liberated filament richochets inside the bulb). Power supplies aside, LEDs typically don’t fail with so much fanfare. Instead, they gradually lose brightness as they age. In the lighting industry, this is known as lumen depreciation, and is a separate failure mode from the catastrophic failure we usually think about.
As it turns out, lumen depreciation happens to incandescent bulbs, too. By the end of their 1,000 hour life, the output has typically dropped 10-15%, but nobody ever notices. With LEDs, the effect is much worse, and the output continues to fall as the device ages. At some point, the LED is no longer producing enough light to fulfill its original purpose, even though it hasn’t “burned out.” Research says that most users won’t notice a gradual 30% drop in light levels; accordingly the industry has defined L70, the time at which the output has dropped to 70% of its initial level, as an endpoint for measuring LED bulb lifetime. Based on how it’s estimated, this measure is typically stated as B50-L70, the point at which 50% of an initial sample of bulbs will retain 70% of their rated output.
Color Shift Happens But is Unpredictable
Something else happens as phosphor-based white LEDs age: they change color. The US DoE’s report on LED Luminaire Reliability: Impact of Color Shift defines four color-shifts (blue, yellow, red, and green) observed in LED lamps, although the yellow shift dominates in high-power white LEDs. This gradual yellowing of the light output results from phosphor cracking, delamination, and thermal effects, since the phosphor temperature can exceed that of the LED junction by 30 C – 50 °C. Modeling and predicting color shift in LEDs is a difficult task, with all of the mechanisms not yet fully understood. As a result, no standards have yet been established for accelerated testing or projection of color stability over time.
Eventually, these effects can be as detrimental to the function of the bulb as catastrophic failure. Given that lumen depreciation and color shift will in time render the LEDs ineffective, it may not make sense for manufacturers to design bulbs with very long electrical lifetimes. It’s possible that the reduced lifetime ratings we see on current bulbs simply reflect better knowledge about actual performance of existing LED technology over time.
Lumen Depreciation in the Kitchen
I’ve seen lumen depreciation and color shift first-hand. In June of 2010, I replaced twelve 65W incandescent PAR30 floodlight bulbs in our kitchen with LED equivalents. At the same time, I also replaced three lights in another room with identical LED bulbs. These three bulbs see much less use, so in preparation for this article, I took one bulb from each location and put them side-by-side to see if I could tell the difference in output. The recessed light fixtures in both rooms are identical, so I expect that the bulbs are exposed to similar temperatures when on: any difference should only be due to aging effects. The results were shocking. Since these two bulbs were in different rooms, I never saw them side-by-side, so didn’t notice how bad the lumen depreciation and color shift had become. Sure, I knew they were dimmer and yellower than when I installed them, but had no idea it was this bad.
These bulbs were advertised with a 30,000 hour lifetime. I estimate the total use at 15,000-20,000 hours. During the 8 ½ years these were in service, one failed completely. Instead of replacing it with a newer bulb which would not match the color of the older ones (or replacing them all), I left that socket empty.
In the hardware store, I noticed new 9-watt BR30 LED bulbs for $5 each. The PAR30s I purchased in 2010 were $45 and consume 11 watts. A quick calculation says that the old bulbs paid for themselves more than three times over in electricity savings relative to the incandescents they replaced, and put that much less carbon into the atmosphere. They may well continue to burn for another 15,000 hours, but after weighing the degraded output and the cost to replace them with brighter, more efficient versions, I’m headed back to the store.
Making Sense of It All
I’ve taken a look at some of the technical issues in LED lighting. Of course, there is more to LED bulbs than lifetime — color temperature and color rendering index (CRI) should factor into any purchase decision. There are also a number of larger problems involved, including issues of economics and sustainability. Some of these are addressed in J.B. MacKinnon’s 2016 article, The L.E.D. Quandary: Why There’s No Such Thing as “Built to Last”, in The New Yorker.
Certainly moving away from incandescent bulbs to more efficient lighting makes sense, but maybe we never really needed 100,000 hour bulbs in the first place. The lifetime of even 7,500-hour bulbs is long compared to the rapid pace of advance in lighting technology. Does it makes sense to buy expensive long-lived bulbs today, when better, cheaper, more efficient ones may be available in the near future?
The oldest surviving incandescent light, known as the Centennial Bulb (click to see a webcam of the lamp), is a dim carbon-filament bulb that’s been burning nearly continuously since 1901 — over 1 million hours. In its current state, it throws off as much light as a modern 4-watt incandescent. Would it have made sense to pay a premium for such “million hour bulbs” at the turn of the 20th century if we had any inkling of the advances that would come in the next 117 years?
The new $5 BR30 LED bulbs I just installed in the kitchen are amazingly bright and crisp: tests with a lux meter show the illuminance is more than 60% higher. Plus, they’ll more than pay for themselves in electricity savings compared to the old, inefficient LED bulbs they replaced.
I bought some of them. They work perfectly
I installed ~40 Mi-Light RGB CCT mr 16 bulbs in my atelier. Some came with bad reception of the control signal (2.4 GHz but not wifi). I programmed them in proper groups, having rgb and two whites is the simply amazing, you can have good fitting white for working and colorful ambient for fun. The reception is not the best and you need the repeat the command quite often for all lamps to adjust, so it does not work as a DMX replacement. However, setting the basic ambient lighting with those is the best bang for the buck.
It sounds like DMX over 433 MHz or 2.4 GHz ought to be the answer.
But then I guess you’d have to make your own light bulbs.
At US Lighting Group we have created a LED bulb with a 190,000 hour lifespan! Check it out for yourself : http://www.uslightinggroup.com
With imported components such as the Samsung LM561 LED, we manufacture the product in house in Cleveland Ohio.
All LED bulbs that I bothered too debug when they failed had a broken LED driver, LEDs were still fine.
Might be a while until we get cheap reliable heat resistant AC-DC LED drivers.
“Remember after electricity is bought by me Its mine do not tell me what I can and cant use it for!!”
Obviously you have never experienced life under Socialism.
Oh well I knew this would happen so I bought several cases of the older style bulbs.
Electricity is NOT yours, you didn’t buy anything, the current returns back to the source…you never own anything in this world, neither your real estate or the air you breathe, EVERYTHING is rented leased or consumed temporarily..even FOOD is returned after being processed
Engineered failures are not confined to electronics.
Years ago I was the electronics team member of a new printing press development. At one time there was a meeting at which programmed failures were discussed – so as to increase maintenance profits.
Various options were discussed and finally it was decided to cause a mechanical part to fail as the cost of replacing the electronics was small and lacked profit.
One old engineer suggested a spring, in the heart of the machine, be designed to fail. This intrigued me, being able to to cause a simple component to fail.
The engineer requested I choose a spring failure time, measured in operations. I chose 12,000 compressions. Off the engineer went and designed a simple spring, which was placed in a testing machine.
The specification the spring must survive 12, 000 operations but fail before 15, 000 compressions. The test was run and the spring failed at 13, 978 cycles.
A couple other items that affect LED lamp life. You will see on some packages “Not Suitable for Fully Enclosed Fixtures” or vis versa. I’d say that a typical lamp installed in a ceiling fan with the glass shroud falls under fully enclosed. Basically the heat has no place to go and burns out the driver. Also I’ve seen some LEDs note the orientation of the lamp, screw base up or down, again, which way is better to dissipate heat.
LEDs are much cooler that you thought..
Real cool..
https://www.bit-tech.net/news/tech/cooling/researchers-tip-reversed-leds-for-cooling-breakthrough/1/
Only Lowes bulbs are nice in my opinion. But still choice matter from one person to another. Haha!
When Led first came out they were the best and the price reflected that. Then every man and his dog started selling it and the price was driven down and with that the quality has been affected (Chinese imports) components sourced cheaper because lets face it the china man does not care. Then we come to the fact that it has totally been marketed wrong with everybody saying there lamp will last 50,000 hours and it will last you 5 years and will achieve a certain amount of lumens and of course the public lapt it up. Most of these companies have not undertaken any testing apart from the well known brands who have there reputation on the line. But even these guys still have a substantial Failures and everybody seems to have there own idea about the colour spectrum for example stating there cool white but 6500k which is daylight. What needs to happen and i believe this is taking place is that LED lamps and fittings will soon have a kite mark. This will help flush out a lot of the cheap crap thats out there. although LED has been around for about 50 years is there any health risks i hear people complain about head aches and eyesight loss might just be that they stare at a computer too long or dont drink enough water. My point is everybody thought asbestos was great and look what happen so do we really no whats going to happen in the future for peoples health who are under constant LED light.
LED bulbs of 100w 13.5w to 15w last 1 to 3 years with us
The 3 year one is on from 7am till 11pm so 16 hrs a day
Its a 15w 100w TCP with a metal heatsink
I’m in the UK so 50hz I don’t know if this is helping
In xp I know metal heatsinks are better
What means of the bulb’s Average Rated Life (ARL) ?
The biggest enemy of LEDs and electronics is heat. Incandescent lights aren’t bothered by heat so the fixtures were never designed to keep the bulbs cool. If you put a LED bulb into an incandescent fixture (most of them are!) You get a hotter light than if the LED bulb was in free air. And like was mentioned in the article, the electrolytic capacitors are the biggest failure problem. Just keep the lights cool and they’ll last longer.
I have been obsessed with LED’s since they first came out. I have built high power flashlights, repaired and modified light bars and now I do LED projects from accent lighting to fixture swaps to landscaping. Leds are pretty amazing, efficient and can last years, yes it’s the driver board almost always. And with that, there are three main components, the Rectifier, the inductor and the transistor (for the PWM). Really the solution to these problems is to partition your house. If all the lights in your house ran off 12v or 24v DC then the failures would go down tremendously. On low voltage projects, the main failure becomes the PSU or chip creep. I have had much better luck with 12v powers supplies really lasting for years while I buy big 30A 24v PSU’s and they last for 2 months with less than 50% load. But anyways if we could shift the lighting in houses to DC and the manufacturers got behind it, I think they could make the lights far more efficient and last considerably longer. And I think you could probably get behind that considering the first thing they do in every circuit you diagnosed is switch from AC to DC and that’s the #1 problem.
Maybe half of LED reliability problems are caused by repetitive thermal shock from turning lights on and off. The hot components create thermal stress that cause marginal failures. A problem that’s been around for a 100 years. There are any number of mechanisms depending on the technology, the classic was the 10x current inrush if the incandescent tungsten filament.
Normally as part of a new design production qualification, new parts are qualified in some way, maybe a 1000 devices are cycled on and off to represent 1000, 000 hours of typical usages, like assuming a device gets turned on and off 4 times a day, etc. The problem is the initial batch tested this way may be OK but subsequent processing variation may increase likelyhood of thermal stress failure. Usually, they periodically test batches but still stuff squeaks through. Eliminating unusual failures that slip through qualification testing require noticing, catching unusual field failures which is difficult to do if field failures are below a below a few percent in first say 6 months.
I agree about outlawing certian lamps. If you want to use led fine use it, but why take away my freedom to use what I want. They gimped down t12 fluorescent when they decided t8 was what people should use. Philips F40/ADV41 was a 3600 lumen 85CRI lamp. No F32T8 can make that amount of light. I have noticed that T12 sold today are 2100 lumen 87 CRI CWX, 2500 lumen 90 cri cw supreme, 2900 lumen 90 garage and basement cri or 3000 lumen 90cri 941. Why is this? I have noticed now that led is the governments choice for people to use philips had detuned their t8’s to 2500 lumens. They used to sell 3000 lumen t8’s in retail stores. I prefer fluorescent T12, I will never accept the deception that has taken another one of my rights away.
One more example, 2 years ago I bought a 11W Led light and sudently stopped to work.
After open the case I fugured out is a 99% copy past from this circuit
http://images.lightstrade.com/201611/201611171534100587.png
With a trick!!!
In order to void overwarm in the original design the Driver IC have a RTH resistor connected to the pin 6 (Temperature automatic adjustment functions set port) to prevent temperature increase.
“output current with the temperature automatic adjustment function.When the temperature is too high, the system will reduce the output current, inorder to achieve the effect of lowering the temperature,
Temperature protection points can set by pin RTH’s external resistor, the RTH voltage will be 1.0 V. The smaller the resistance, the lower the temperature protection point.
If the RTH feet up, then the point temperature protection for the default value is 139 degrees Celsius.”
Guess what is missing?
The RTH resistor, not implemented.
My 5 year light bulb lasted 5 months.
Sadly LED bulbs only last much longer in THEORY.
And since 99% are made in China, it is very common to have them fail right out of the box or within days of use.
If built in the USA to much better quality control standards, it is quite possible to expect 25,000 or more hours of life.
The people who think the 1000 hr designed life of an incandescent bulb was a conspiracy to rip people off, have forgotten to take into account the cost of the electricity consumed. Bulbs are cheap and electricity is expensive. The overall cost (original bulb + replacements + electricity consumed) is higher for 2000 hr bulbs than it is for 1000hr bulbs. This is because 2000hr bulbs consume more electricity for the same light output, due to the fundamental physics of heated tungsten filaments. 1000hrs was set as a standard to maintain consistency in lifetime and brightness between different manufacturers, and low running costs.
When you have a cartel that is restricting manufacturers to a specific product that removes consumer choice and it is ALWAYS done to maximize profits. Consumers are not all one size fits all. A consumer may have a fixture that requires a lift truck to reach. Or a 12 foot ladder. They might choose to pay the higher electricity cost so as to reduce bulb change frequencies so they don’t have to get on a 12 foot ladder twice as often.
The race-to-the-bottom is a myth as long as the manufacturers are required to adhere to truth in labeling. For example take paint. You can buy a $12 gallon of white paint that takes 3 gallons and 3 coats to cover a ceiling because the paint is so cheap it is practically transparent. Or you can buy a $25 can of paint that does it in one coat. If the industry/cartels/government forced the paint manufacturers to say on the $12 can that it is a “30% coverage product” while the $25 can said “100% coverage” THEN they would be helping the consumer because the consumers would know what they are paying for. However the cartels/governments usually don’t want to increase consumer education they want to preserve a monopoly.
And don’t think the government also doesn’t have an interest in increasing product sales – they do. More product sales means more jobs, more sales taxes collected and more income taxes collected. The more the government can cause money to move in an economy the more taxes they can collect when the money cycles around. The LAST thing the government wants is a consumer spending $100 on a product that lasts 10 years if they can get the consumer to spend $20 on a product that does the same thing that only lasts 1 year. Even in a situation where the consumer only needs to use a product for a year the government doesn’t want them buying the $100 product, using it for a year, then selling it to another consumer for $80 because no sales taxes are collected and that product may be used by that consumer, sold again, and end up moving through 10 other consumers before it finally wears out, none of who will be paying transactional taxes. The government ALSO does not want people REPAIRING products for exactly the same reason unless the repair is so complicated that it requires a specialized technician to do it because then that tech is contributing taxes and there’s transactional taxes that can be applied.
Consider the “tire disposal fees” that governments are not loading down on places that sell new tires. They absolutely want consumers buying a 20,000 mile tire instead of a 60,000 mile tire because the government gets $15 for a disposal fee instead of $5. In cars they want the consumers buying a hybrid gas burner that produces thousands of dollars in fuel taxes instead of an electric car they charge themselves from solar panels that produces zero fuel taxes and zero utility taxes.
As far as LED longevity the problem is the fixtures as has been said already. We bought a house that had been custom-built back in 1973 by someone who had a “thing” about wall sconce lighting. Maybe they were trying to evoke the old gaslight lighting who knows. But every one of those edison-base fixtures mounts the bulb horizontally on the wall behind a frosted shade. Scads of air circulation around the bulb. We replaced all the bulbs with LEDs and no problems but at the same time the table lamp fixtures that mount the edison base bulbs vertically, the bulbs are always being replaced. Makes no difference if the bulb is right side up or upside down, if it’s a vertical mount it does not last as long. As an experiment I replaced several outside wall mount lamps with “bulkhead” fixtures that completely hide the bulb so the fixture looks OK mounted either vertically or horizontally – the vertical mounting fails faster.
The reality is that the complexity of the LED bulb affecting reliability makes for an interesting engineering discussion but the simple fact is that when all incandescent bulbs are gone from the shelf except for specialty lights, and mass production and economies of scale has gotten the LED bulb pricing down to 50 cents a bulb, the edison base fixtures will still be king, and nobody will care that the bulb has to be replaced every 3-4 years or so. And I think the same thing will happen with LED “fluorescent” tube lamps – the standard form factor there is the 4 foot LED tube and the price on those right now at Costco is at $5 a bulb, and still heading downwards – eventually that will be a dollar a bulb and everyone will be using the “2 pin at each end 4 foot replaceable tube” although likely in bypass fixtures.
If the average consumer moves into a house that’s wired for 24v LED lamps or any esoteric stuff like that – basically anything they can’t buy at the home improvement store – any lighting that they have to call a specialist to replace – then out in the garbage it will go.
As per this article only 10% failures are due to LED bulbs and 60% due to driver circuitry
If you couldv only replace the driver circuitry, it would reduce the costs and the electronic wastes
We need to push for standards so drivers and LED lights are standards. Same wattage light should have a compatible driver
So you can replace only one and they are available from multiple vendors
” Doubling the life of a lightbulb (by reducing the surface power loading of the filament) results in a 10 % reduction in luminous efficacy.”
I believe you have that backwards. The efficiency of LEDs is higher at lower power. By reducing the power you increase the efficiency (more lumens per watt) and the lifetime of the light bulb at the same time.
Modern bulbs have a constant current driver IC that uses resistors to set the current it will drive through the LEDs. You can change the resistor value (or simply destroy one of the resistors with side cutters if the circuit uses two resistors in parallel) and it will reduce the current supplied. BigClive on YouTube has some videos about it. If you buy a bulb with twice the power rating you want, you can halve the power this way, and maybe it will last forever?
The slowly-diming failure mode is creepy. Our lights will literally start gaslighting us.
https://en.wikipedia.org/wiki/Gaslighting
I just had an “allume” brand LED, 230 volt bulb fail after less than 2 years (1 month short of 2 years actually) in my workshop with a usage of about 15 minutes a day at most. That’s around 4,400 hours (estimate). I’ve had generally poor results compared to the claims made for LED bulbs. I’m starting to think they have built in obsolescence. Where’s your market if they last forever?
If i owned this property i would run the lighting circuit on low voltage & get low voltage lamps if available. The power supply could live next to the consumer unit.
Look at the efficiencies and projected lifetimes of the Philips Dubai Bulbs. No wonder they don’t want to sell them anywhere else.
…. not considered in this article is the manufacturing impact of LED bulbs, with the extra plastic, materials and electrical circuits it seems we are creating much more toxic waste with the LEDs. are they really better? using less power and creating more waste and pollutants? seems it would be impossible to determine.
What absolutely baffles me is that the (known) effect of irreversible retinal damage caused by (ageing) LEDs isn’t mentioned anywhere in this post. As LED bulbs age, so do the secondary emitters (AKA “phosphors”) in the yellow/orange SR layer on top of the blue/violet primary emitters: they break down as a result of the constant bombardment with short-wavelength photons. What is typically noticed as a shift towards a higher light temp is actually an indicator that this layer has lost its protective function and is now letting high amounts blue and UV light pass, resulting in the known effects as excitation of glucosides within the eye (reduced acuity, perception of glare) as well as damage to the retina. In the animal model (rats), these effects could be observed after only 2 weeks of exposure with blue LEDs. (Background in human factors / ergonomics; committee work for our national standardization agency, research work in environmental medicine)
I switched from filament bulbs to CFLs in rooms without dimmers. These did last well as did the filament bulbs.
I swapped to LED lighting. The G10 LED bulbs are lasting well, but the Standard UK bayonet ones are an utter load of rubbish!
Bathroom light 6 months, top of the stairs not used a lot, 12 months, never left on for long!
In my lounge I have some decorative “fancy filament” old type GLS bulbs and some are on all evening every day for hours. They are on dimmer switches and I have changed two in 20 years!
I have no confidence in these LED bulbs at all. I took some apart to find the fault so far isn’t the power supply but one or more of the series wired LEDs have failed.
I got my oscilloscope out and used the tracker. Found 2 LED chips blown on one lamp. The rest I could light up with the tracker.
I get the impression that these LED lamps are overdriving the LED chips and that’s why they are blowing.
I need to find a bulb/lamp that is better quality.
These ones I have that are no good are made by CED electric. There are 15 LED chips on the main PCB and two had blown. The previous one that failed one had blown.
It looks like in the future I need to do my research and find the best lamp/bulb that will do the job and possibly pay a bit more for them.
using many lower wattage LED bulbs instead of one big one wil make them last longer i suspect. By running cooler,
Led bulbs are lee than useless in all enclosed light fixtures.
They fail much sooner than the 25cent incandescent bulbs they replaced.
Led bulb power supplies create a lot of heat so the bulb base MUST be kept cool for the bulb to last.
I have yet to see any led bulb last longer than a CFL or incandescent in any enclosed fixture.
As always they were merely a save the planet lie that never came true.
Made in China by slaves so they don’t last and are merely funding our own deaths
Most of my expensive Philips LED bulbs bought about eight years ago exhibited another failure mode. Annoying flickers when they heated up. Not a continuous flicker but a haunted house / your electricity is about to fail type flicker. At least they paid for themselves in that time.
This article argues that it is fine the LED bulbs have planned obsolescence, because they deteriorate over time and technology gets better so it might be time to change the bulb anyway after 20k hours or so.
Well, the LED bulbs I buy fail much faster than that and I do buy from reputable brands. I have to replace them practically as often as the classic lightbulbs, if not more. They may use less energy, but they generate electronic waste, so in terms of environmental impact it is back to square 1. The difference is that the lightbulb producer corporations get more money instead of the electricity provider company.
Why we can’t have nice things.
All semiconductors will fail eventually. Due to the fact that are manufactured using diffusion processes. This means that they are “doped” in some fashion with an element such as boron, gallium, arsenic, etc. They are then heated to high temperatures to diffuse the dopant into the crystal structure. This movement of the dopant creates the electronic junctions in the device giving it it’s particular electronic properties. However, at room temps, this movement doesn’t stop just slows down. When the device is heated be it by use or amibient or poor manufacturing practice these junctions are altered thus changing the electrical properties sometimes leading to failure. Eventually,even at room temperature, this same phenomena is still taking place therefore the will not last forever. Heat expedites the process in all cases. Semiconductors do not last forever!
I’m glad to see this article is still accepting comments since the conclusions the writer came to 4 years ago are wrong.
For starters while there may have been semiconductor advances, as far as the manufacture of LED light bulbs they have actually reverted. The modern LED bulbs you buy in 2023 are LESS advanced, and last far less than the LED bulbs you could buy 5 years ago. The reason is that the light bulb manufacturers have been designing for cost savings not longevity and over time have learned more about how to make the bulbs as cheap as possible with lifespans that are as close to 1 year as possible. This is a marking thing. People raised on incandescent bulbs have been trained to replace light bulbs at most around the 1 year mark – that is, the general public accepts a 1 year lifespan on a light bulb. The “early market entry” companies that made LED bulbs all thought that if they produced a bulb that would last 5-10 years the general public would shift to a much higher unit cost, understanding that if they paid say $5 a bulb they would get a 5 year bulb instead of paying $2 a bulb they would get a 1 year bulb, and the savings would also be in the aggravation of not having to get a ladder/stepstool out to replace a bulb. Except, while the general public will always go for the $2 bulb over the $5 bulb even when they know it’s trash, based on the hope that “maybe this time I’ll win the great deal” This same principle is why states make far more money selling $1 lottery tickets than $5 lottery tickets.
We have also seen the replacement of the early manufacturers with the mainline light bulb makers who have always made cheap disposable light bulbs. Almost as if the early manufacturers made sure to go out of business before their 10 year warranty bulb customers started cashing in warranty bulbs at the 9 year mark. Makes me wonder how many of those early manufacturers were owned by holding companies funded by the mainline bulb makers.
Another fascinating thing is you go into the home improvement store and 90% of the light fixtures are LED fixtures costing $50 with integrated non-replaceable LEDs, 10% are Edison base fixtures costing $10 that can take replaceable screw in “incandescent” bulbs even though they do not sell incandescent screw in bulbs at all. Yet the lifespan of the expensive 1 time throwaway fixture is no greater than the screw in replaceable LED bulbs. However the stores also have a huge shelf of screw in LED bulbs. What is happening is that the majority of people are buying fixtures that will take screw in bulbs and they are buying screw in LED bulbs yet a significant number of consumers are “fashionistas” when it comes to light fixtures and are actually eager to replace the light fixture every few years just to get a different “look”
We are also seeing a very large increase in “designer LED bulbs” with LED bulbs that look like old filament bulbs, LED bulbs that change color, etc. Technically there are no advances here at all. It is all engineering for “fashionistas” The bulb companies are hoping to get the general public trained to use a variety of different styles of light bulbs in the home. That way, instead of having a box of plain “soft white” 100 watt and 60 watt bulbs in the closet that will fit every single light fixture and lamp in the house, todays homeowner must have a shelf of 2 dozen different shapes, sizes, colors, lumens of LED light bulbs for replacement.
The “fashionista” aspect is also continuing to produce a series of poorly designed fixtures with the Edison screw in bases. With a LED bulb the best mounting practice is base-bottom or base sideways. Base-top with the bulb hanging down, is the worst position since the electronics are in the base and heat kills them. Some fixtures like “bulkhead” outdoor fixtures, can be mounted vertically or horizontally and look OK either mounting direction with the bulb base facing down. Others such as ceiling fixtures use traditional mounting orientations and mount the base sideways. But, far too many of the Edison screw in base fixtures use the suboptimal bulb-hanging-down base-up orientations even when they could be redesigned to use base-down.
About the only bright spot in LED fixtures are in “fluorescent tube” fixtures. There is a brisk business retrofitting fluorescent light fixtures to take LED tubes, by gutting out the old fluorescent ballasts and this does not seem to be out of the ability of the DIYer since the home improvement stores stock the fluorescent tube tombstones and other parts. And the tubes increasingly are the “gut out the ballast” types instead of the “hybrid” types that will work with the electronic ballasts. The LED tubes themselves are also very long lasting, produce excellent light, and many now are switch-selectable for color on the tube itself.
Overall the LED lighting industry is around a grade “D” in my opinion. Way too much electronic waste in non-bulb replaceable light fixtures, and non-optimal bulb orientation fixtures, and deliberate designing for 1 year replacement bulbs. The few bright spots are that the general public has not completely accepted integrated LED bulb/fixture combinations and likely will be less accepting of these as time passes and people get burned on frequent replacements of expensive integrated fixtures, and the LED tube lighting, and the LED industry making an effort to produce mini base clear candelabra bulbs with filament LEDs so that our hanging candelabra fixtures don’t look horrible after a bulb replacement.
As for the “semiconductor diffusion” issue mentioned by the last poster, well that may be so but I have electronic devices that are 20 years old and still going strong that use surface mount integrated circuits, and have been powered almost continuously, so I’m not really going to accept that one. There are also mil-spec components, open up any Apple Computer “bondi blue” iMac with the candy color housing and the glass picture tube and their circuit boards are covered with milspec electrolytic capacitors that are NOT spitting their guts all over the board, and still power up (even though the machine itself is obsolete and there has not been a new build of IOS for it that will run on it for years) The reality is that the average vacuum tube had a much shorter lifespan than the average semiconductor part. It is simply that most techs don’t have the understanding of standard practices in vacuum tubes nor an understanding of the electronics shift from vacuum tubes to semiconductors because they were not alive during vacuum tube days. “forever” was never a goal for these products. “Lifetime” was the goal. The idea was a person could buy something basic such as a radio in their early 20’s when they were setting up their home separate from their parents, and have it last until they were in their 80’s. And while that was never attainable with vacuum tubes, it certainly is attainable with semiconductors. (as proof, the Voyager 1 and 2 space probes are still in operation 51 years after launch)
thanks for a very interesting story. I am the photographer and help with the website for the longest burning light bulb in the world located in fire station 6 in livermore, ca. I can point you to several links an more stories of our bulb…..