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Manufacturers routinely claim that their LED light bulb can last from 20,000 hours to 50,000 hours:

Philips LED OSRAM LED Feit electric

Anecdotes, such as this one suggest otherwise. Daily mail wrote:

  • More than a quarter did not meet claims of a 15,000-hour life
  • Disappointing result comes despite claims of them lasting 25,000 hours
  • Some even fell below the legal minimum of 6,000 hours

Are LED manufacturers exaggerating the life span of these bulbs?

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Of the article referenced in the first link one should only accept the observed statistics of failed LEDs. The "theory" part that relies on the claim that every single electronic part has the same failure rate as a light bulb does not hold - an average CPU has millions of transistors and according to that theory your brand-new computer should be dead before you have finished pushing the power button ... – Hagen von Eitzen Jan 17 at 14:41

In an October 2015 test report by the Dutch 'ConsumentenBond' (consumer organization/watchdog) they report back on an earlier test started in 2013 (no link available) where 5 lights each of 24 types from 13 brands were tested.
At that moment they had been running 20000 hours. They were switched 8 times per day: 2:45 hours on, 15 minutes off.
75% of those lights were still running after 20000 hours. They mention the results for specific brands. Although not available everywhere, I'll list here how many died per 5 per brand (fractions can occur when several types per brand were tested):

  • Albert Heijn, Kruidvat, Hema, Calex, Panasonic: 0
  • GoGreen: 1
  • Verbatim (one type): 3
  • Philips, Osram, GP: 1.5
  • Megaman : 3
  • Ikea, Pharox, Verbatim (other type): 5

I was unable to find the life expectancy claims of the 2013 batch (only the phrase with claims up to 25000 hours). Assuming that the current test period does not substantially exceed the claimed periods, my tentative conclusion would be '75% meet the claims.'

The 2015 test results are also available in that report (in Dutch of course), but those lights had only burned 2000 hours by then (1 had failed by then).

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Could you provide a translation for the headers of the table on the final page of the report? I tried running it through Google translate, but its choking on the diagonal text and showing mangled gibberish instead of something minimally understandable. imgur.com/SZLX0lP – Dan Neely Jan 15 at 22:34
    
@Dan That imgur link did not work. Here are the diagonal texts: Price, Test result, Durability and reliability to switching (counts for 30% in test result), Efficiency (light yield) (counts 30%), Light quality (20%), Luminosity measured divided by specified number (15%), Luminosity in lumen on packaging, Measured luminosity, Efficiency (yield) in lumen/watt, dimmable. Note: these are the results for the 2015 batch. – Jan Doggen Jan 15 at 22:54
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@DanNeely: Reactive power and power factor are related -- the first is an absolute quantity, the second is relative to the real (dissipated) power drawn. The actual equation is PowerFactor = RealPower / sqrt(RealPower^2 + ReactivePower^2) It's also equal to the cosine of the phase angle between voltage and current. – Ben Voigt Jan 16 at 0:08
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"Still running" is not the metric they use to say that a bulb is still within it's life span. It is based on lumen depreciation. Usually that threshold is 70% of initial output. They usually say something like "lifespan estimates determined once 50% of a sample of bulbs drops below 70% original lumen output". – fredsbend Jan 16 at 0:31
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@matt_black, Re, "Their light output does not deteriorate over time as all phosphor-based lights do." Most "white" LEDs are phosphor based. In virtually all household LED lamps (not counting the expensive, variable color kind), the light source is a broad-band yellow phosphor mix excited by a deep blue LED chip. en.wikipedia.org/wiki/Light-emitting_diode#Phosphor-based_LEDs – james large Jan 16 at 19:59

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