question about "25 year" 3M LED Advanced Light Bulb

[steve2470]

http://www.3m.com/product/information/LED-Advanced-Light-Bulb.html

http://solutions.3m.com/wps/portal/3M/en_US/LEDAdvancedLight/Home/Retail/

I bought it yesterday for a light for my front door. The bold claim is 25 years. The small print is 27,500 hours, which is 3.14 years if run 24/7/365. I might use it for 5 minutes a day just to light my entry way, because I don't feel the need to have an outside light burning all night. 5 minutes a night = 1700 minutes a year roughly, or theoretically a lot more than 25 years if the bulb lasted that long.

25 years is marketing BS, correct ? Assuming normal weather conditions on a covered front porch (largely shielded from rain, hail, direct sunlight, etc), there is no way a light bulb could last that long, right ? FWIW, the light bulb is encased in a typical decorative light fixture housing (with small glass panes encasing the bulb) one would install by a front door. How many years can you expect ?

Thanks in advance, Steve

[ohnoyoudidnt]

1. Judging by how long the so called 5 year light bulbs

I buy last. Yes, I'm going with BS.

Edit- now thatI think about it, the outside lights last a lot longer than the inside lights. So it probably has something to do with how often they are turned on and off.

[NYC_SKP]

7. I'm guessing you were buying CFLs, which are shit.

If you were buying LEDs, you'd know it.

They have only been out a couple years and started off and more than $20 each (more actually I bought one in 2006 for $100).

[steve2470]

8. yea this bulb was $20

I was a tad shocked but paid it anyway due to the longevity and convenience to me.

[NYC_SKP]

14. Over a 20 year period of 6 hour use, you'll save hundreds of dollars over other lamp types.

I had students do a similar comparison when I bought that first Feit bulb at Lowes in 2010.

Link to a cost comparison chart:

http://en.wikipedia.org/wiki/LED_lamp#Comparison_to_other_lighting_technologies

Impressive.

[steve2470]

15. yes those are great savings, well worth the $20 upfront investment ! nt

[ohnoyoudidnt]

12. You guessed right.

I'll try a couple LED lights. If they work as good as claimed, it sounds worth making a full switch.

[NYC_SKP]

2. "and it lasts up to 25 years." Emphasis on "up to". I toured an LED light manufacturer, Bridgelux.

I'm a huge fan, full disclosure.

I saw a rack where they were testing them. Life span is always an estimate, and a conservative one at that.

A 50,000 test, non stop, would take more than five years, by which time new technology has been developed, so the numbers are just a safe guess.

Also, most bulbs aren't on all day or all night. Many household applications are just a few hours daily, this bulb life in years is based on a 3 hour/day daily use.

So, no, I wouldn't call it bullshit. I'll bet that the industry has agreed upon a 3 hour/day standard for purposes of comparison.

[steve2470]

3. ok, let's talk theoretical here

As I said in my op, I envision only having the light on, maybe, 5 minutes a day. 10 at the very most. The light bulb is outdoors, as I said. Any guesses on how long it will last ?

[NYC_SKP]

9. I have maybe forty, or more, and only one I bought in 2006 failed.

And that one failed probably because it was emerging technology.

They didn't come to stores until 2010, but I already had a lot of the chips, and I used them to light salt water aquariums. I did ruin a few of them because of the salty water environment and no lens, but the light was great!

Lowe's got them in 2010, Home Depot a couple years later, I now have almost 100% LEDs and none have failed but for the one 2006 model.

I have them all over the place, the shop, kitchen, bathrooms, outside.

My guess is that your LED lamp (the technically correct term) will last as long as you own it.

[steve2470]

11. it would be awesome if I never have to replace it lol

Of course in Florida, we do get hurricanes

[Major Nikon]

4. Is the bulb fully enclosed?

Most LED bulbs like this aren't designed for fully enclosed fixtures due to heat issues.

The bulb is warranted for 5 years, so save your receipt.

[steve2470]

5. It's fully enclosed but it seems the hot air could escape ?

You would have to see the fixture.

[NYC_SKP]

10. Thermal management is built into the base.

Thus the heaviness of it and the fins usually present, the base is like a heat sink and thermal diffuser.

I think it will be just fine in that fixture if that fixture is vented (as it would be for an incandescent lamp).

[steve2470]

13. it's too bad I don't have good pictures of the fixture

My layman's impression of the fixture is that hot air can easily escape. I could easily be wrong.

[Major Nikon]

16. Maybe, but I wouldn't count on it

By enclosed, I'm not sure if they mean 'sealed' enclosed, or just covered on all sides.

At any rate, 3M makes a commercial version of this bulb which is rated for use in enclosed fixtures, but this reduces the lifespan of the bulb (by how much they don't say). It appears you have the retail version which is not rated for enclosed fixtures. The commercial version is considerably more expensive.

These bulbs are also rated for enclosed fixtures. As you can see they are also quite pricey, but they have a lifetime warranty. Shipping costs also add to the price unless your order exceeds $150.
http://earthled.com/collections/switch-led-lighting-store-buy-switch-led-light-bulbs

[steve2470]

6. the fixture looks like this, but fastens horizontally to an outside wall

[TreasonousBastard]

17. 27,500 hours is theoretically possible, but...

that tends to be a median mark the way lighting manufacturers figure it-- with testing showing about half won't make it that far. In the old days of incandescent lighting, 10-15,000 hour, and even higher, bulbs for such things as EXIT signs and traffic lights were common, although they achieved that by putting out less light per watt. I forget exactly how long our fluorescent tubes where rated for when I worked for DuroTest, but 10,000 hours rings a bell, and some lasted even longer.

You might notice that the lumens per watt for both the LED and the CFL are almost identical, so your electrical costs won't be that much different. The CFL probably won't last long outdoors, but it's usually a lot cheaper, so it's only a question of do you want to spend the extra money to replace a bulb every 25 years instead of 5. That's assuming you get the 25 years.

Most people will sell the house, change the fixture, or just forget when they put the bulbs in long before that.

There's also nothing saying that the LED will last that long at all outside, though. Most are designed for indoor use and might not be able to take the thermal shock of being turned on in winter. A lot of CFLs can't take that shock either and blow out prematurely outdoors, and the only way to know is to put them in and see what happens. FWIW, I suspect those CFLs in the dollar store will have the shortest lives.

LED chips are also monodirectional, so you want to be sure that the matrix inside is designed for omnidirectional light. Some pretend to be omnidirectional, but only throw light out through the top half of the sphere. This would make them pretty much useless in the kind of fixture you are using. They would be fine, however, in a fixture that held the bulb upside down.

LEDS are pretty good and will eventually take over, but they are not magic.