Based on the rate of failure of LEDs I have encountered, I decided to produce a list of the current common lightsources, sorted from the longest life lamp and the shorted life lamp.
The lamps that have the longest and the shortest life afe (According to my thinking):
1. Mercury vapour (Longest life)
2. Halophosphors T12 and T8 fluorescent on magnetic rapidstart (T12 or american T8) or preheat (T12 and european T8)
3. Induction (Philips QL, Osram Endura/US Sylvania Icetron)
4. HPS
5. LPS
6. Metal halide
7. 2-pin PL magnetic
8. SBMV
9. "Lumilux" T8 (Triphosphors low mercury lamps) magnetic
10. T5 HE/HO
11. Incandescent
12. Halogen
13. CFL
14. LED (The shortest life).

With CFLs, I think it really depends on the type of lamp and the application.  We have a few 13W GE Helicals that are going on 1-2 years of service.

It also depends on how you take lumen depreciation into consideration.  Which is a longer lasting lamp, an HPS that produces 75% or its initial output at 24,000 and zero at 30,000 or an MV that produces only 60% of its initial output at 24,000 but still produces over 50% at 30,000?

Under good conditions and best quality lamps i would rate the lamp life as this :

Longer life first :

1. LED
2. Mercury vapor
3. Fluorescent on Perfect Start, Rapid Start or Programmed Start


4. Fluorescent on Switch Start (include TC-S/D/DD with internal starter)

5. Cold cathode discharge lamps
6. HPS


7. MH




8. Self ballasted CFL


9. Halogen
10. Incandescent



With low qulity lamps everything will be low....

We have appliances with blue LEDs since 2000 if not earlier. in many of them the blue LED is an indicator that lights brightly in blue for all those 12 years. hort calculation : It did over 100K hours and still goes strong. And i did not yet see a failed indicator LED where the LED would burn out. Similarly, we have appliances with other color LEDs since the 80s if not earlier. A red indicator in an electric panel from the late 80s did 200K hours by now. It can be dim but thats how LEDs were back then. And LEDs got better since then

So LEDs can do many hours - when treated nicely. When powered at reasonably low curernt and not allowed to heat up in an enclosure. Problem is with the LED lamps (and floodlights and streetlights) where a total of several watts (or more !) of LEDs are crammed in tiny space and have to run hot, at high currents etc. No wonder they fail.....

So when using LEDs use them in the way which is best for them - LED strips. In those strips are long conductors and there is distance between the LEDs, which makes them run cold and have their right lifetime. If you want a point source there are better lamp types for that

Ash: I rated the LED lifespan such a low level, because of these failed LED lighting encounters in the last Thursday:
1. Failed LED tube in Cinemall mall ( Approximated installation time ).
2. Failed LED recessed downlighter ( Approximated installation time ).
Also, the storage of Carmel hospital have two new AEG phones, that within less than a year, their red LEDs that backlights their buttons dimmed out and are barely visible .
Also: CCFL lamps, have longer life than regular fluorescent lamps, because as they aren't relys on a thermionic emission and they don't requires an emitter. Turning on, don't shorts their life, and they haven't a filament to burn out.

Do nightlight incandescents (the kind with the candelabra base) count?

mrboojay: Nightlight incandescents should have similar life to regular incandescents, also their tungsten filament is inside a vaccum instead of a nithrogen/argon/krypton atmosphere.

mrboojay: Nightlight incandescents should have similar life to regular incandescents, also their tungsten filament is inside a vaccum instead of a nithrogen/argon/krypton atmosphere.

Yes and no.
Yes, the lifetime match the ordinary vacuum incandescent dependency on the temperature. Well, due to the fragility of the thin filament the mortality curve is flatter and shifted towards shorter life.

But these low wattage lamps are mostly designed with rather cold running filament (~2500K iso 2700K; in many fixtures even below 2500K because of the series connected resistor), what compensate the effects, so make the lamps actually last longer, if they are not exposed to any vibration (they are placed so, nobody could touch the fixture) and the inrush current is limited (within many nigh lights is a resistor intended to protect the switching triac from lamp flashover at EOL, what does the double duty in limiting the inrush current as well).
\So in many such fixtures the lamps run longer, of course all that is on the expense of efficacy: 7W lamp does not give more than 20..30lm...

Ash: I rated the LED lifespan such a low level, because of these failed LED lighting encounters in the last Thursday:
1. Failed LED tube in Cinemall mall ( Approximated installation time ).
2. Failed LED recessed downlighter ( Approximated installation time ).
Also, the storage of Carmel hospital have two new AEG phones, that within less than a year, their red LEDs that backlights their buttons dimmed out and are barely visible .
Also: CCFL lamps, have longer life than regular fluorescent lamps, because as they aren't relys on a thermionic emission and they don't requires an emitter. Turning on, don't shorts their life, and they haven't a filament to burn out.

They are examples of how LEDs should NOT be used

In the fluorescent tube ou pictured, it is the ballast that failed. Maybe it is one dead tube in the entire parking lot - can happen with any lamp type. Maybe there are several failed - then it means that they are made with bad quality ballasts and the problem is not the LEDs. It makes no sense to compare life of bad quality devices - for example we all like magnetic ballasts since they last "forever" but i seen magnetic ballasts to fail one after qanother after few months in normal use (no stuck starters) - obvious why when you see how nasty they are made

In the recessed can it is probably the ballast as well, however the can is also an example of BAD application for LEDs - they are crammed in 1 tiny space



It comes down to this :

Typical LED thinking : We want LED to retrofit this MH downlighter, so we put the equivalent power of LEDs in the same space

How it should be : We want a downlighter so lets use the most appropriate lamp for it, which is MH or TC-D. Or if we want LEDs then we should not use a downlighter at all but long LED strip that will have the same power over large surface area



I have a USB LED light (wuith 1 5mm LED) that was bright and nice and it EOL'd in about 20 hours. I then checked the value of resistor that was there : the LED was running at 50mA ! - no wonder it died so fast.... Put in new identical LED with a resistor that gives it 13mA, bright enough for me and it is still going strong for a lot of time now

Maybe in that phone they abused cheap "indicator" LEDs (the tiniest SMD possible which is not meant for lighting) instead of high brightness LEDs, and just drived it at high current, then no wonder it failed....

And another issue : The PCB in the phone is getting bent a bit when dialing on the keypad. With some bad soledering job (as can be expected in a cheap phone), combined with lead free soldering (which needs better precision in manufacture process, and dont expect that to be done properly in a cheap product), LEDs can be simply be broken out of the circuit



CCFL lamps vary but sharing some of my experiences :

CCFL lamp in the backlight of a good quality computer monitor lasts about 10 years of intermittent use (T0.8 lamp, 7mA, HF ballast). T8 on Switch Start can last longer than that. HPS lamp lasts longer than that in years but it is also doing less hours every day than the monitor

Glow discharge indicators (in panels etc) vary by color - the red Ne ones usually last for decades, green ones very often blacken on the inside so they are still lighting but the light is not coming out

Ash: In the case of the LED tubes: These are designed to operates directly from the mains without an external gear, as they incorporates a simple capacitive nightlight driver in them. The magnetic ballast simply needs to be bypassed. So the LED tubes that stopped working, needs to be replaced.
There were tens of these no working in the Cinemall.
There was also one that directed a T12 fluorescent lamp without a starter on a choke ballast (Glowed very dimly with brightness vibrating and striations).
Other tubes had part of their LEDs dimmed slightly.
In the case of the LED recessed cans: They were built from scratch, and replaced PL and MH cans.

Some of them work straight on the magnetic ballast and use a "stuck starter" that comes with them - so that you dont have to modify the fixture, just insert the tube and thats it (the tube takes power from 2 pins on 1 side, the other side is just shorted). They dont rely on the magnetic (they have HF inside them), they just take way lower current than the fluorescent tube so the extra choke in series does not have much effect (other than PFC'ing the HF ballasts input current)

I dont know if the tubes there are the type that can work with magnetic ballast or that requirer it to be removed. I also dont know if the ballast in them is capacitive or HF

If you sey it is capacitive then no much wonder why they burn out, it is about the worst option of ballast possible. Besides, if they by any chance connected a capacitive ballasted tube to a magnetic ballast, the balast cancels out some of the capacitor's impedance and so will overdrive the LEDs or even cause immediate failure

If a LED tube is designed well (thermal design) and made with proper HF ballast with high quality components (no overdriven LEDs, marginal quality electrolytics etc), i'd expect many years out of it



Part of LEDs dimmed - may be result of LED overdriving - maybe due to low quality of the tube and maybe due to running a capacitive-ballasted tube on magnetic ballast (if it did not burn out right away)



The LED cans still contain lot of LED power crammed into a small can. Uness they use enormous cooling on the other side (which more often they don't), the LEDs will overheat in there simply because of fixture size / power dissipation is too high for LEDs

Want recessed cans ? use TC-D or MH which have no problem to work in high temperature

Want LED recessed cans ? If there is no huge finned heatsink above it then it's going to burn out quite fast

Currently, no MH or PL cans, remained in the Cinemall (Except spotlights for installation either independently or on busbars). All of the lighting of the ways in the Cinemall are lighted by LED cans only.

@Medved:  We have a bulb that looks like a nightlight bulb (it is behind a deffused glass) in our microwave that is going on about 20 years of use.  It is the original bulb.

@Medved:  We have a bulb that looks like a nightlight bulb (it is behind a deffused glass) in our microwave that is going on about 20 years of use.  It is the original bulb.

Well, how long is the microwave running per day, so how many hours the bulb made? The magnetrons (the microwave generator, so the heart of the oven) is usually designed for lifetime of 10khours, making a lightbulb with such life span is not a big deal...
And with similar appliance bulbs, the efficacy is by far from being the most important design factor, so I won't be surprised it is designed to operate at low temperatures, in order last longer...

I don't know.  Do on and off cycles count toward it's life like standard incandescents?  It has had a lot of those.