Do LED bulbs dim over time

John_Gray

It seems very likely that LEDs will suffer from entropy, like almost everything else!

Stompa

Yes. I seem to recall that the quoted lifespan of an LED bulb is the time it will take for the brightness to diminish to 70% of its original level.

Sandtree

Grey_Critic said:

***I think they were cheap bulbs the Mrs bought in one of the cheaper home bargain type of shops  ***

Please don't be fooled by the label - M&S clothes are made in the same sweat shops in Bangladesh as cheaper brands. Many *own brand* foods are made on the same production lines of leading brands - just different labels.

Location of production does not indicate the quality, technically nor does the working conditions of the employees. Dont be fooled into thinking that just because two products are made in the same country that the budget item is of the same quality as the luxury item. 

Even in the UK a factory can be making a "wool suit" that is low quality light weight wool fabric with a fused lining and all machined. The same factory can make a "wool suit" from a high quality heavy wool fabric using a floating canvas lining and hand padding plus sew the button holes by hand. Both will carry the same 100% wool made in UK label but are not comparable products in quality nor price.

I agree you cannot automatically assume that brands go for better quality but neither can you assume just because its made in such a country or that two brands use the same factory that the quality will be comparable. 

longwalks1

Thanks again all, I've checked and on one of the bulbs, the lense had fallen off!  cheap rubbish. I've ordered 6 Phillips ones online so will replace the cheapies and go from there

JustAnotherSaver

Hmm.

Well based off some replies here, I guess my eyes must be broken and rather than some of my LED bulbs dimming, there must be some activity beyond this world going on.

Whatever the weather, in simple terms the LED bulbs were dimmer in appearance. Whatever the scientific goings on behind that outer casing, the effect is what someone would refer to as dimming.

Therefore the bulbs dimmed.

Had this on both LED bulbs in the car on occasion and also LED bulbs in the house.

jamesd

Eyesight also dims as we get older. Part of the natural aging process is gradual loss of sensitivity in the retina and gradual darkening of the lens. Cataracts of several types are also routinely encountered in people by the age of 60 and those can introduce more nuanced dimming, blurring or other effects.

But LED dimming is also normal and probably faster.

Chickereeeee

Out of 12 led g10 halogen replacement lamps installed 4.5 years ago, two have failed (one dim/flickered, one dead) in the past 6 weeks. And they are Phillips lamps too, not cheap ones. I am beginning to think 30000 hrs is 'optimistic'....

Sandtree

Chickereeeee said:

Out of 12 led g10 halogen replacement lamps installed 4.5 years ago, two have failed (one dim/flickered, one dead) in the past 6 weeks. And they are Phillips lamps too, not cheap ones. I am beginning to think 30000 hrs is 'optimistic'....

The problem is that 30,000 is an average... what you really also need to know is the standard deviation to know how much variance from that you can expect. By default you know 50% of bulbs wont last 30,000 hours 

[Deleted User]

JustAnotherSaver said:

Hmm.

Well based off some replies here, I guess my eyes must be broken and rather than some of my LED bulbs dimming, there must be some activity beyond this world going on.

Whatever the weather, in simple terms the LED bulbs were dimmer in appearance. Whatever the scientific goings on behind that outer casing, the effect is what someone would refer to as dimming.

Therefore the bulbs dimmed.

Had this on both LED bulbs in the car on occasion and also LED bulbs in the house.

Your eyes aren't broken - some statistics on the light output of LED's will help. There are two types, one is short term, eg minutes after being switched on as the heat rises and the LED becomes less efficient and a longer term permanent dimming that occurs over hundreds of hours:

Short term dimming due to heat:



https://www.cnet.com/home/energy-and-utilities/daylight-toned-led-light-bulbs-which-one-should-you-buy/


Long term dimming due to age



https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/led/lumenMaintenance.asp

JustAnotherSaver

[Deleted User] said:

JustAnotherSaver said:

Hmm.

Well based off some replies here, I guess my eyes must be broken and rather than some of my LED bulbs dimming, there must be some activity beyond this world going on.

Whatever the weather, in simple terms the LED bulbs were dimmer in appearance. Whatever the scientific goings on behind that outer casing, the effect is what someone would refer to as dimming.

Therefore the bulbs dimmed.

Had this on both LED bulbs in the car on occasion and also LED bulbs in the house.

Your eyes aren't broken -

I know.

I can't comment on what people here are seeing (or not) but my own experience says that they dim, end of.

When we moved in i changed all the bulbs to LEDs on the basis of they'll pay themselves off. They use no power basically, right? And they last forever, right?

I've bought various brands over the years and have spent enough money and gone through enough bulbs to be able to say

1) LEDs can dim.

2) They can go kaput just like that

3) Well known brand does not = better quality or that they last longer.

Most of my bulbs are E14 with some B22s. I've also used LEDs and SMDs in cars for years. Some fade, some seem to last forever.