Sure! If there’s one thing I love to talk about more than lighting I’m not sure what it would be.
Let’s get the good news out of the way: The LED source itself. It’s designed to last (maintain 70% of its brightness) for 35-50,000 hours. But that’s at 25C and in 3 hour bursts. Even then I’m willing to praise it as a decent source of light that will last a really long time when the weather is nice.
http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/lifetime_white_leds.pdf
Now we get into the parts nobody wants to talk about. The electronics.
Heat is the enemy of LEDs. The phosphors degrade and migrate from the center of the lens, causing the source to shift closer to its natural blue color. The electronic driver inside begins to have issues and does what all sensitive electronics do without a fan, fail. Should your LED be mounted outside in, say, Texas, you’re obviously pushing your luck. But your typical semi enclosed wall sconce? About 60C, with an 8 watt source. Ceiling can lights, especially air sealed ones required in California? Now we’re starting to see some heat, as your 65 watt light bulb can raise the temperature of a 10’ cube by a degree in an hour. Imagine what happens when it’s in a 6" diameter tube after a few hours.
Now, as for what the claims the manufacturers are actually making, we have to look at the warranty information. If you buy a new car you can get a six year warranty on it. The manufacturer is saying that with all the various moving parts in various conditions with normal wear and tear, six years or sixty thousand miles is something they openly claim to be an acceptable life on the car that they are willing to take responsibility for their work. Cars are pretty complex, so that’s pretty impressive. How hard can a lightbulb be?
The TCP products you mention above don’t really have a working warranty page, so I can’t be sure of their exact claims, but in the meantime we’ll look at the other larger manufacturers: Feit, Philips, and Cree. They are 2 years, 1-3 years (depending on initial design hour claims), and 10 years, respectively. And there are use limitations of 6-12 hours a day for these. Cree is the only one saying these will last 20,000 hours and even then it’s not over 20 years. Because nobody is actually saying that. They haven’t even manufactured these products for 20 years to know, let alone tested them for that long.
There is a 114 year old incandescent still burning, but no manufacturer is claiming all incandescents will burn for a million hours. LED lamp lives are part marketing, part specific math, and part hope that nobody calls them on it. I’ve been specifying LED products for over 10 years now and have seen a lot of long-term installations go awry, ones that used products in the $300 per linear foot pricerange or $600 per downlight.
The diode might be up to it, but everything behind the diode is not, and the entire system isn’t being accounted for when claims of 18.3 years of lifetime are made. It’s a bold lie made worse by people not calling them on it because they don’t know any better. And even if these products do last that long, half of them are scheduled to fail prior to that. The ones that do survive will see increased power use with decreased light output and gradual color shift (even after one year of use).
I hope this has added some clarification as to why their claims are essentially meaningless. I’m not looking to attack, only to correct the numbers thrown out by the industry. They are blind hope and a fast-moving marketplace that forgets quickly, and I don’t like to see people throw their money away without knowing the product’s limitations.
