Does It Hurt LED Bulbs To Turn Them On & Off ?

Mostly no.

The simple answer is "not at all".

Mostly this is probably not something you have to worry about. And I don't think any of the experts on this forum are even sure that constantly turning on and off an LED bulb does hurt it.
On what do you base your conclusion?

Unfortunately there are no hard statistics in this discussion.

Ikea rates some of their bulb life by number of on/off cycles, not operating hours (usually). Ikea is a reputable supplier of bulbs. They must have reasons.

(Maybe) not coincidentally, a number of Ikea low-cost bulbs use switching regulation
versus linear regulation common in other brands. I have confirmed two by opening up, including the 40W equiv. selling for under $1 each. I believe this is to allow a single design with only minor adaptation to operate at either 110v or 220vac. The two bulbs checked convert line voltage to around 80v dc. That's getting a bit off the topic though.

Thermal on/off cycling can and does reduce lifetime of components and electronic
assemblies, including solder joints. I have been directly involved in such testing, although not for LED bulbs, and for qualification, not lifetime testing (only correct functionality or early failures).

Say, in a very cold environment with a bulb which runs hot, allowing to run and heat
up, then switching off and cooling down, several times per day, may shorten the life compared to letting it run continuously for some period (say 8-10 hours). I think it will vary with the circumstances.

Switching regulators themselves may have failure modes due to frequent cycling,
possibly items such as input capacitors, but I do not know specifics.

Dave
 
On what do you base your conclusion?

Unfortunately there are no hard statistics in this discussion.
That is correct. Unfortunately it seems very difficult to find any hard data and testing on this.

Here is some things I was able to find:

On-off cycling can cause catastrophic failure in LED systems, which can be due to thermal expansion mismatch between the system's layers. This mismatch can cause stress on the interface material, leading to fatigue failure.

According to one study that looked at an LED-based incandescent lamp replacement, LED systems fail faster when power is cycled than when they are continuously powered on. The study found that when the delta temperature (the temperature change during the on-off cycle) increased, the system failed faster and showed faster lumen depreciation. The study showed the dominant failure mode to be solder joint failure.

A graph is shown comparing between two LED lamps, one that was left continuously on, and the other that was continually cycled on and off. They both are comparable up to 2500 hours, but then after that, the relative light output of the cycled lamp begins rapidly falling off, reaching 80% lumen output by 3000 hours, and around 60% by 3500 hours.

Some of the LED lamps failed after between 1500 to 3500 on and off cycles, which seemed to show a relationship with temperature (between 45°C to 70°C). A typical cycle consisted of 3 hours on, 1 hour off.


Thermal cycling, the process of a device moving through hot and cold states, is one of the biggest areas that causes failure in electronics. If thermal fatigue occurs, multiple systems within the devices can be affected, resulting in warpage, solder weakness, breaking or cracking - and eventually, if left unmitigated, overall product failure.
https://www.ansys.com/blog/thermal-cycling-failure-in-electronics

One study on LED bulbs found no catastrophic failures up to 2000 cycles, but they did "fail" in terms of lumen output dropping below the 70% threshold. The rate (number of required cycles to achieve this) was dependent on temperature.
https://www.lrc.rpi.edu/programs/solidstate/pdf/Narendran-LS14-2014.pdf

This comes from the GE website (one of the big three manufacturers that produce LED lamp products), under the section "LED Lighting Maintenance: How to Extend the Lifespan of Your Lighting Fixtures":
"Additionally, the rapid temperature changes that come with a lot of on/off changes can cause materials to expand and contract, which is another source of potential damage. By minimizing on/off cycling and reducing the frequency of turning on your lights, LED bulbs experience less stress and last longer."
https://www.gelighting.com/articles...ce-how-extend-lifespan-your-lighting-fixtures

However, the U.S. Department of Energy site says this:
"The operating life of a LED is unaffected by turning it on and off. While lifetime is reduced for fluorescent lamps the more often they are switched on and off, there is no negative effect on LED lifetime. This characteristic gives LEDs several distinct advantages when it comes to operations."

For CFL lamps, they give this advice to try to maximize lifespan:
"A general rule-of-thumb is this: If you will be out of a room for 15 minutes or less, leave it on. If you will be out of a room for more than 15 minutes, turn it off."
 
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However, the U.S. Department of Energy site says this:
"The operating life of a LED is unaffected by turning it on and off. While lifetime is reduced for fluorescent lamps the more often they are switched on and off, there is no negative effect on LED lifetime. This characteristic gives LEDs several distinct advantages when it comes to operations."
Interesting articles. Apparently the u.S. DOE thinks turning LEDs on and off has no impact, everyone else thinks it does.

Dave
 
Interesting articles. Apparently the u.S. DOE thinks turning LEDs on and off has no impact, everyone else thinks it does.

Dave
It's a pretty messy question actually. Are they considering the LEDs themselves or the entire lamp including it's driver? The driver is what typically takes the bulk of the inrush current in a properly designed bulb.

Thinking about the LEDs themselves, a PWM driver is essentially turning the LEDs on and off thousands or millions of times per second. Doers this age them faster than leaving them on? And how does the lower temperature but continuous stream of inrush spikes on PWM driven LEDs compare against the thermal degradation effects of leaving the LED on all the time?

I think the tendency to compare LED longevity to incandescent lifetime negates the fact that an incandescent bulb's resistance changes sharply between initial power-on and normal operation. That jolt from the initial power-on can physically twist the filament, causing microscopic fractures in the filament that eventually add up to significant weakening. Think about that "centennial bulb" in the fire station in California - it's been running continuously for 120 years, partly because it's (almost) never turned off. Sure the filament design has something to do with it also, but if they turned it on and off regularly, it would've been long gone by now.
 
I think the tendency to compare LED longevity to incandescent lifetime negates the fact that an incandescent bulb's resistance changes sharply between initial power-on and normal operation. That jolt from the initial power-on can physically twist the filament, causing microscopic fractures in the filament that eventually add up to significant weakening.
A tungsten incandescent filament has 14 times less resistance in its cold state than when it is on (heated to 2700-2900K, which is 2427-2626 °C). That results in very rapid heating when it is turned on. (It takes less than half a second to reach the maximum temperature)

One possible way to extend the lifetime of incandescent bulbs might be to put them on a special circuit to more gradually apply an increase in power to them. Even if this occurred within a timespan of 1 or 2 seconds.

Most commonly, when an incandescent filament finally blows out, it is when the lamp has been off and then it happens immediately right when the lamp is turned on.

Think about that "centennial bulb" in the fire station in California - it's been running continuously for 120 years,
Incandescent filaments that are operating below 2700K can last a very long time (regardless if they're being turned on and off or not). However, this simply is not practical (in most situations) because the resulting light is so orangish, and has far lower light output efficiency.

The special incandescent bulbs that used to be used in traffic lights were rated to be able to last up to 10 times longer than ordinary household incandescent bulbs. (The high maintenance cost and problematic nature of frequent replacement made the greater expense and significantly lower light output efficiency worth it)
 
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A tungsten incandescent filament has 14 times less resistance in its cold state than when it is on (heated to 2700-2900K, which is 2427-2626 °C). That results in very rapid heating when it is turned on. (It takes less than half a second to reach the maximum temperature)

One possible way to extend the lifetime of incandescent bulbs might be to put them on a special circuit to more gradually apply an increase in power to them. Even if this occurred within a timespan of 1 or 2 seconds.

Most commonly, when an incandescent filament finally blows out, it is when the lamp has been off and then it happens immediately right when the lamp is turned on.


Incandescent filaments that are operating below 2700K can last a very long time (regardless if they're being turned on and off or not). However, this simply is not practical (in most situations) because the resulting light is so orangish, and has far lower light output efficiency.

The special incandescent bulbs that used to be used in traffic lights were rated to be able to last up to 10 times longer than ordinary household incandescent bulbs. (The high maintenance cost and problematic nature of frequent replacement made the greater expense and significantly lower light output efficiency worth it)
In one of my previous jobs we had a large room with a very high ceiling that required a genie lift to reach the light bulbs, and they were constantly burning out. We finally decided to replace those 120v bulbs with 130v bulbs and they lasted forever. That was an excellent investment.
 
Incandescent operation can be interesting but now confined to a minority of use.

The 130v bulbs last longer but take a hit on efficacy, that's the tradeoff.

A side thought, I wonder how well LED bulbs designed for household 120v hold up in the higher i.e. 130v (usually rural) environment, particularly the linear type which uses LED stacking. The difference is dissipated by the regulator IC. Depends on the dominant failure mode for particular design, how much
lifetime is shortened (also depends on ambient temperature etc.)

LED bulbs driven by PWM at thousands, to perhaps hundred thousands per second are not going to suffer the same stress as turning on, heating up, turning off, cooling down at a slow rate i.e. minutes to hours. The "thermal inertia" is too large to allow substantial rapid temperature changes. It will settle on temperature of the average duty cycle.

Dave
 
At the current price point for household LED bulbs, buy a few packs to put on the shelf and use em however you want. You'll likely only have to replace them once or twice in your lifetime, if that.
 
You'll likely only have to replace them once or twice in your lifetime, if that.
Unfortunately my (and many other people in this forum) experiences contradict this. Sure, the manufacturers will claim LED bulbs will last practically forever. But in my experience, with a group of typical cheap LED bulbs which are left on 5 hours every day, 38% of them will stop properly functioning after only 7 months, and then maybe another 34% will stop working after 14 months. It will not be too likely any will make it to the two and a half year mark.

(When I'm talking about typical cheap LED bulb, Feit Electric would definitely be included in that, and GE LED)

The average cheap LED bulb seems to last only slightly longer than the old style incandescent bulbs. (And I am talking about before government regulations forced the "energy saver" incandescent bulbs that glowed at a whiter 2825 to 2890K. This was just before halogen capsule incandescent bulbs became the standard)
 
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The average cheap LED bulb seems to last only slightly longer than the old style incandescent bulbs.

This has not been my experience at all. It might not be the bulb's fault. Do you have a whole house surge protector? The supply to your house might be suspect.
 
I replaced all of the old style incandescent bulbs in our house with cheap LED bulbs when we moved here in 2019. I have only had to replace one of them in the last five years. I guess I just got a good bunch of LEDs.
 
My experience too. One(expensive) bulb out of many that i replaced after moving in,in coincidentally 2019.
I have security flood lights that are flat like an ipad with a bank of maybe 50 tiny LED's and i run those bedtime to wake time and after two years or more they are still going strong.
As far as flashlights i don't know how long these LED's are supposed to last. Time will tell.
 
My experience too. One(expensive) bulb out of many that i replaced after moving in,in coincidentally 2019.
I have security flood lights that are flat like an ipad with a bank of maybe 50 tiny LED's and i run those bedtime to wake time and after two years or more they are still going strong.
As far as flashlights i don't know how long these LED's are supposed to last. Time will tell.
I had a couple of premature failures that I suspect were due to heat buildup. These bulbs were operating upside down in semi-enclosed glass flower-shaped domes, where the heat would rise and get trapped around the neck of the bulb. I fixed that issue by looking for bulbs that were rated for fully enclosed fixtures.
 
I had a couple of premature failures that I suspect were due to heat buildup. These bulbs were operating upside down in semi-enclosed glass flower-shaped domes, where the heat would rise and get trapped around the neck of the bulb. I fixed that issue by looking for bulbs that were rated for fully enclosed fixtures.
Had the same issue. Only mine was right-side up. LED shaped like a traditional bulb inside a glass fixture. Blew within a couple of weeks. Fixture was a major headache to unscrew and re-attached. very poorly designed. Took a look at the new LED bulb I just installed. Said, "Screw it." Didn't bother with the fixture. I can live with it attached to the hallway ceiling. That was several months ago. Dawned on me later on what took place with that original LED bulb.
 
This has not been my experience at all. It might not be the bulb's fault. Do you have a whole house surge protector? The supply to your house might be suspect.
Are you sure we are talking about the same incandescent bulbs? I am talking about the ones from 1994-1996. Not the ones that became standard in 2004-2005.

It's also possible, depending on how your house is wired, that the voltage could be a little lower. Just a tiny decrease in voltage could make a very significant difference in incandescent light bulb lifespan. (a 2.5% decrease in voltage will result in a 46% increase in lifespan but a 6% decrease in light output, very roughly)

Like so many things in the world, it's just "a little more complicated than simple".
 
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Are you sure we are talking about the same incandescent bulbs? I am talking about the ones from 1994-1996. Not the ones that became standard in 2004-2005.

It's also possible, depending on how your house is wired, that the voltage could be a little lower. Just a tiny decrease in voltage could make a very significant difference in incandescent light bulb lifespan. (a 2.5% decrease in voltage will result in a 46% increase in lifespan but a 6% decrease in light output, very roughly)

Like so many things in the world, it's just "a little more complicated than simple".
I was talking about LED bulbs failing prematurely and the possibility of frequent power surges from your electric service being the cause of LED bulb failure.
 
Unfortunately my (and many other people in this forum) experiences contradict this. Sure, the manufacturers will claim LED bulbs will last practically forever. But in my experience, with a group of typical cheap LED bulbs which are left on 5 hours every day, 38% of them will stop properly functioning after only 7 months, and then maybe another 34% will stop working after 14 months. It will not be too likely any will make it to the two and a half year mark.

(When I'm talking about typical cheap LED bulb, Feit Electric would definitely be included in that, and GE LED)
Ironically, the biggest failures of bulbs I've had were with Philips & Cree bulbs, and that's back when they were going for nearly $10 a pop. Plenty of cheap ones have gone bad on me too, but so far the pricier ones have been the problem.
 
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