This post was written by Keith Dawson for UBM Tech’s community Web site All LED Lighting, sponsored by Philips Lumileds. It is archived here for informational purposes only because the All LED Lighting site may go dark at any time. This material is Copyright 2013-2015 by UBM Americas.


A Quarter of LED Bulbs Don't Last

A British consumer testing agency ran 46 varieties of commercial LED light bulbs through a simple lifetime test. Almost 29% failed before 10,000 hours.

It seems like, just as we all suspected, LED bulbs bought off the shelf don't reliably last anything like the 25,000 or 50,000 hours that many of them advertise.

The British consumer testing agency called Which?, equivalent to Consumer Reports in the US, bought five bulbs of each of 46 varieties of LED lamps on the market -- 230 bulbs in total. In tests "carried out by Which? and [its] European partner organisations," the bulbs were run for 165 minutes and turned off for 15 minutes, repeating until they failed.

Short timers
Sixty-six bulbs, 28.9% of the total, didn't make the 10,000-hour mark. For five out of 46 varieties tested, the majority of bulbs in the sample failed short of 6,000 hours. The EU has new regulations coming into effect on March 1 that require LED bulbs sold there to last 6,000 hours.

Which? did not make a lot of details public. Like its US counterpart, Which? reserves the details of its testing to its paying members. The minimal amount of information present in the public account at the link above does not list the brands or models of all the bulbs tested. Nor does it refer to the L70 criterion widely used in the lighting industry to mark the useful lifetime of an LED. It sounds like when Which? says the bulbs failed, it means they stopped working altogether.

Again, details of failure modes were not given. But I would be willing to lay odds that many or most of the failures involved drivers, soldering, or assembly problems.

Naming (some) names
Which? did name the companies behind two of the bulbs that failed most quickly: TCP and Ikea. (Those two bulbs were the only ones of the earliest-failing group sold in the UK, according to the consumer group.) Ikea said the bulb in question had passed its own tests and those of an outside agency; while investigating, it had removed that model from sale in the regions in which it had still been available.

TCP said it already knew about the problem with that bulb, and that it had already been withdrawn from sale before these tests. The company said it was no longer dealing with the supplier behind that particular bulb.

Which? concludes its brief public report with "We're in the process of testing the life span of many more LED bulbs." We'll probably be hearing about more short-timers in due course.

— Keith Dawson Circle me on Google+ Follow me on Twitter Visit my LinkedIn page, Editor-in-Chief, All LED Lighting