CNET Reader Dadar asks:
Are the "lifespan" claims by manufacturers proper? I've read numbers ranging from 50,000 hours to 100,000 hours, often with plasma TVs at the higher end of that scale compared to LED and CCFL LCDs.
I would have thought, being solid-state devices, light emitting diodes would have had a greater lifespan than their fluorescent counterparts. Hearsay also puts plasma at the bottom, but numbers I've found show the opposite? Are any of these true?
All claims by manufacturers should be taken with a grain of salt, but you pose an excellent question.
The first thing we need to discuss is what manufacturers mean by "lifespan." This doesn't mean that after a certain amount of use, the TV will just stop working. This rating has nothing to do with parts or warranty coverage. Most manufacturers don't even mention lifespan on their Web sites.
What they're talking about is brightness. The generally accepted method for measuring lifespan is the number of hours of use until the TV is half as bright as it was when new ("half brightness"). The TV is still watchable, it's just not as bright. Nearly all new TVs are very bright, so they'll largely be watchable at the end of their "lifespan" ratings, assuming no other issues.
The fact is this: all TVs get dimmer with age. How many years it will take before it's unwatchable depends on a lot of factors. A few generalizations can be made, though. For one, the brighter the TV, the shorter its life. Turning down the TV's backlight control, or turning down the contrast control on a plasma, will extend its life (and lower your electric bill). Will watching a dim TV give you mediocre enjoyment for 30 years? Probably not, but it will help.
What's the longest lasting TV tech? Hard to say. Plasmas are often the only technology that even lists lifespan, and this is almost always a claimed 100,000 hours. The florescent lamps in CCFL-based LCDs age just like any other florescent lamp, and I've seen them rated for 30,000 to 60,000 hours (sometimes more). The "white" LEDs used in LED LCDs will also dim over time. There is little published data on LED lifespan (as in, the companies aren't talking), but it's assumed to be similar to CCFLs.
As far as the long awaited
What do these numbers mean? Well if we go with these numbers (all we have, at the moment), and you watch 5 hours of TV every day, a plasma will reach half brightness in around 54 years. Even the lower rating on LCDs would mean 16 years before half brightness. If you watch more TV than that, well, the math is pretty easy. Even running 24 hours a day, you're still looking at more than 10 years with a plasma till half-brightness.
To be fair, each technology ages differently, and not entirely equally. CNET TV reviewer David Katzmeier is doing, with interesting results. There have been reports of some LED LCDs experiencing a color shift as they age. There are multiple CCFLs in LCDs that use them, and while they're likely to age in a similar fashion, it's possible they won't, leading to dim areas of the screen (horizontally). But again, we're talking many, many years of use before this is even a possibility.
Keep in mind that with LCDs, what's aging is the backlight (both CCFL and LED). In extreme cases, the LCD layer itself can age, but it's largely the backlight that's the issue. Technically, you can replace the backlight of an LCD, but I dare anyone to prove that this is remotely cost effective. You're better off just buying a new TV.
And that, as much as it's sure to anger many, is the overriding advice here. Plasmas and LCDs are reliable and long-lived. Will they last as long as that ancient console CRT you've had in the basement since the '70s? Maybe, maybe not, but why would you want them to? Ten years ago, flat-panel TVs were incredibly expensive and looked like crap. Today, they're cheap and gorgeous. Imagine what amazing 70-inch 4K OLED you'll be able to buy 10 years from now. TVs get larger, cheaper, and better every year. So even if your TV "only" lasts seven years, you'll be able to replace it for far less money than you paid for it with something that performs even better.
In other words, don't worry about lifespan.
Got a question for Geoff? First, check out all the other articles he's written on topics like , , , and more. Still have a question? Send him an e-mail! He won't tell you what TV to buy, but he might use your letter in a future article. You can also send him a message on Twitter: @TechWriterGeoff.