Lifetime claims often can't be substantiated, and it's not only the small players that are guilty of exaggeration.
Over the last month or so, we have been discussing LED luminaire performance in the field after a few years. And, of course, we have a never-ending dialogue in this community about the perceptions of this or that LED lamp's integrity. It seems there is no single correct answer.
In some businesses, there is more confidence in the information when the "life expectancy" predictions are based on large amounts of historical, factual data. An example is the insurance industry, where thousands of actuaries, over many decades, have been shown to be quite good at estimating -- on average -- how long this or that person will live or remain in good health, based on specific quantifiable factors.
In recent years, giant financial firms -- beyond just the hedge-fund math modelers -- have taken this kind of analysis to a new level. The field is called "predictive analytics." Fidelity Investments, in one of its Boston-area groups, has one of the largest information technology investments in this arena because of the size, complexity, and diversity of the global funds it manages for individuals and corporations.
The firm number-crunches historical events and trends to predict the effect on its clients of the smallest financial, legislative, geopolitical, or technology blip on its screen. It's computer modeling for future events, but based on historical quantitative factors -- deadly serious stuff with trillion-dollar implications.
Have a look at this five-year-old real-world paper on LED luminaire reliability, a.k.a. life expectancy, in terms of lumen maintenance. (The figure above comes from that DOE Building Technologies Program paper.)
We know that we were bombarded 10 years ago with "LEDs last forever" messages, and there was a torrent of Asian LED imports claiming 100,000-plus hours. We seem to have come to our senses. Increasingly, on the packaging of Lighting-Fact-labeled LED bulbs found at Home Depot, Lowe's, etc., we see life expectancies back down at 25,000-35,000 hours. Much of this is driven by building evidence of many failure modes as LED products continue to evolve, as well as a number of recalls, while vendors are under extraordinary pressure to cut manufacturing costs.
Unlike some of the historical fact-based assumptions of the predictive analytics used by Fidelity, the predictions in the LED industry can sometimes seem laughable. Of course, there really is no solid history when it comes to today's luminaires with white power LEDs. They did not even exist eight years ago in their present form.
A parallel universe
What's my point? If you check out Lithonia/Acuity's new I-beam high bay LED luminaires -- or GE/Albeo's ABHX series or Hubbell's HBL series -- you will see a claim of 100,000 hours. Lithonia even goes so far as to claim 93% lumen maintenance at 100,000 hours. Wouldn't you just love to visit Lithonia and ask, "What hat did you pull that rabbit out of?"
There is no question that some folks are living in a parallel universe.
What has happened is that the large companies, pursuing giant contracts, have allowed their marketing departments to take over. "If our major competitors are claiming XYZ, we also have to do it." Never mind whether you can prove it. Just hire a math whiz to come up with some equations that suggest it "could happen." Not one customer in a hundred will challenge his math. If GE says 100,000 hours, but Hubbell says 50,000, the Hubbell sales manager knows he will lose the $3 million order for warehouse fixtures.
In the power supply business, everybody throws around MTBF numbers, as we have recently discussed. At least with MTBF, there is some relationship to actual lengthy field data experience for all the components used in a design. But the life expectancy numbers for LED luminaires are totally driven by the "life expectancy" given to the luminaire maker by its vendor for the specific chip used. That chip number, in turn, is based on a small sample, tested for a fraction of its expected life, under conditions that are unlikely to be the same as those expected for the chip in use.
We've seen "lily-white" Fortune 500 companies with 100,000-mile warrantees creating cars with defective ignition switches or exploding air bags; drugs with fatal side effects; fail-safe oil rigs that fail. Let us chuckle now when Acuity/Lithonia, GE/Albeo, Hubbell, and a dozen other "leaders" in their field switch from lighting companies into delicatessens offering baloney any way you want it sliced.