/ Home & Energy

Are your LED light bulbs failing too soon?

LED light bulb

We’ve previously reported that LED light bulbs are falling well short of their bold lifespan claims. Our latest tests suggest they’re getting better, but can you really expect them to last 25,000 or even 50,000 hours?

You’ll see a lot of LED bulbs claiming to last for 25,000 hours or more. And compared to compact fluorescent bulbs, there’s no doubt that they’re more durable. But too many LED bulbs don’t last for even half as long as they should.

Last month we shared our test of 410 LED light bulb samples. We revealed that 75 of those (18%) failed within 10,000 hours, even though they all claim to last much longer.

We also tested 185 of those 410 bulbs for a longer period – all of them claimed to last at least 15,000 hours, but 69 (37%) had failed by that point.

Your LED bulb experiences

The data wasn’t a surprise to many of you. BJ is disappointed with his LED bulbs:

‘I purchased six LED bulbs for my kitchen. After four days one had stopped working and another had two LEDs in a second had failed. Also in the same purchase I bought an ES LED bulb for the hall. Half the bulbs (banks of LEDs) went out after 45mins. Not impressed.’

John was similarly frustrated:

‘I have purchased 30 LED bulbs over the past year as I have been replacing conventional bulbs with LEDs as and when they fail. Out of the 30, five have failed and one has developed a horrible green hue. That’s a 20% failure rate in bulbs that vary between a few months and a year old. Retailers have generally been very good about replacements, but it’s hassle and surely the point of LEDs is to save energy AND to save time/money in replacing bulbs.’

Which? Convo regular John Ward isn’t keen on spending over the odds for LEDs:

‘If LED’s were just a bit dearer than CFL’s I would take a chance and install them everywhere, but at £7 – £20 each for the popular types, their endurance very unpredictable, and possibly going to pop far too soon, I shall stick with what I have.’

Signs of improvement

Our results show that LED bulbs are getting better, however. Looking just at older bulbs, 28% failed by the 10,000 hour mark. For the latest batch, made up of bulbs produced since new tougher EU regulations were brought in, that was down to 6%.

We’ll have to wait to see whether there are similar improvements for the newest bulbs reaching 15,000 hours – they haven’t reached that point in the test yet. We’ll continue to measure how long LED light bulbs are lasting, and we’ll update you on what we find out.

Tell us about your experiences with LED bulbs. Have you noticed a difference between older LED bulbs and those you’ve bought in the last year?


I have had repeated failure of Modo GU10 units, fitted by an electrical during a complete rewire of my house. Surprisingly, the replacements I got from Poundland are doing great……

A quick look at the reviews on the Amazon site would have put me off Megaman Modo lamps.

Which? did not test this type but another Megaman lamp performed well last year.

The February 2018 magazine has a review of LED bulbs and on page 67 there is advice on some common problems including premature failure, flickering and DAB radio interference.

One point is that LEDs in enclosed fixtures can overheat, particularly if next to old-style bulbs. I have bought numerous LED bulbs and not one has had this advice on the packaging.

A friend has been keen to replace a set of halogen lamps in the kitchen and I suggested that they bought one to see if there was a problem with radio interference. He did buy one but bought one online rather than from a shop.

It did not take long to fail, though three of the LEDs remained working. Looking at the lamp it’s a thin disk with a dozen LED chips on one side and five components on the back – a bridge rectifier to make it work on AC or DC and four SMD resistors – for anyone who is interested. The resistors are under-rated and blackened and charred and there are no fuse or other safety device.

The lamp was purchased via the website of a rather well known company they trust and was supplied by one of the many smaller companies that supplies the goods. If you would not buy electrical goods from a street market then is it a good idea to buy online from an unheard of company?

eddie lovett says:
19 June 2018

Is the problem not really caused by the electricity power supply ? We have many spikes constantly occurring and with over and under voltages all the time.

Hi Eddie – I suspect that high voltage spikes are one cause of premature failure of LED and CFL lamps and have commented about this in other Conversations. If more than one lamp fails at the same time this is very likely to be caused by a voltage spike.

One of the problems is that it’s difficult to accommodate spike suppression in the small space of a lamp cap. There is no excuse for not using spike suppression in lamps with a separate driver, such as 12V LED lamps or sensibly designed fixtures where the LEDs and driver are separate and the risk of overheating of both is reduced.

I don’t know what voltage limits a mains LED lamp can handle. I’ve used 12V LEDs from a specialist supplier and they work fine between 10 and 30V.

There’s an interesting article in the mag this month about “smart light bulbs”. There big advantage is you can turn them on and off from places where you lie down. Their average price is £44 – some 10x a standard LED that you’ll have to turn off at a light switch. You’ll need a £600 smart phone as well as possibly a hub, costing up to £80.

I wonder whether it’s the LEDs that are smart, or the market managers persuading Which? and some consumers that they are the bee’s knees.

Quite so. Another case of a solution looking for a problem.

After around a hundred years of electric lighting starting to come into ordinary homes most people are smart enough to have cracked the problem of how to turn the light off after they’ve gone to bed. Of course, it was so easy to blow out the candle and today’s people need a similarly simple solution. The only drawback I can see to this device is the need to find your smartphone in the dark when you want to switch the light on again. There is also a slight risk that turning off one light could accidentally turn off the one in the bathroom where someone else is still up – or does each one have a unique signal that has to be programmed into the smartphone? Another thing to contend with.

We’ve just bought a nice pair of bedside lights – and you can switch them on and off without leaving the comfort of the bed or trying to find the phone!! Alternatively, people could go to bed with Alexa: “Switch off the light please and play some soft music. Night, night.”

Sweet dreams.

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And what happens when hubby goes to the pub with his smart phone and app, and the lady of the house needs to turn on the lights? Perhaps a phone call to the saloon bar will elicit the necessary instruction?

Thanks Duncan. It seemed odd to include a DC to DC converter but I can see the point and they are very efficient. I expect that colour changing LED lamps will prove increasingly popular and that ones that can be controlled from a phone will provide a relatively inexpensive way of adapting a home to meet the needs of old and disabled people.

I wonder how much thought has been given to the security of these devices.

duncan, I’ve never considered an LED bulb (nor a CFL) as a repairable item. You’d have to ensure they were not put in lights where they might get too hot.

No, but it can be interesting to dismantle failed bulbs to find out which component failed.

I’m not sure about “inexpensive”. You’ll probably need at least 6 bulbs to cover the house, plus a hub, and (assuming you’ve already got a smartphone) that could cost around £300.

We have remote controlled plugs in the living room, and they could be in other rooms, where conventional lamps of any kind are switched on and off. They are relatively inexpensive.

I have, in our hallway, a couple of rechargeable LED torches that sit in holders plugged in to sockets. They automatically switch on if the supply fails (as it did in the wind the other night). Very handy to find your way to the fuse box and phone.

I said “relatively inexpensive”, Malcolm. If fitting some remote-controlled lighting and other appropriate modifications to your home it might save you having to go into a care home, which might cost £1k per week.

You can buy light switches operated with a remote control as well.

Both wall switches and ones for table lamps etc. When I was a young man I built a sound activated switch using germanium transistors from old computer circuit boards, which were cheaper than new transistors.

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I think for standard light bulbs ES E27 screw caps were a better bet than B22D bayonet caps. They were secure (could be used with a vibration proof lampholder where The larger (E40) versions were widely used in industry, street lighting and the like. Although, for some strange reason, the Europeans were slightly bigger than the American’s who used E26 and E39 (unusual for the Americans to have something smaller than the rest of us 🙂 ).

However, BC capped lamps were useful in many situations. For example they could position a lamp accurately where that was needed – car lights for example – and the lampholders could be designed to only accept specific bulbs.

I hate lamps with screw caps because they can become loose (which is why the motor industry stopped using them) or jam – common with oven lamps.

Duncan – it was probably the heat from old fashioned bulbs that damaged your bakelite lamp holders.

The vast majority of street lights were (many still are) equipped with screw lamp holders for E27 and E40 Edison screw lamp caps. They are subjected to continual vibration – low and high frequency – and did not come loose. Nor did they become stuck.

I’m not sure what relevance street lights have to household lamps. This information is from Wikipedia and refers to the vibration and jamming problems I mentioned:

Screw bases have a number of disadvantages compared to the bayonet fit type:

– The metal screw itself forms one of the contacts for the circuit. If the lighting system is not correctly wired, or a lamp is plugged into a non-polarized outlet, the metal screw can become live, presenting an electric shock hazard to anyone attempting to change the lamp.
– It is possible to over-tighten the screw, risking breaking the bulb or separation of the glass envelope from the metal base and leaving the base in the socket, especially when subsequently attempting to unscrew it.
– If the lamp becomes loose in the socket due to vibration or under-tightening, it can lose contact with the center contact and stop working until it is tightened. The bayonet type is resistant to vibration and much less likely to become loose.
As the metal thread carries current, any arcing can jam the thread.
– Corrosion is more likely to jam a screw thread than a bayonet fixing.
– Screwing in and unscrewing the bulb places more force on the glass envelope.[citation needed]
– When fixing anything with a cable attached, the cable will twist as the screw is turned.

Screw bases have a number of advantages compared to the bayonet fit type:

– Screw bases are more suitable for small size bulbs
– A bulb fully screwed home is more secure than a bayonet fit bulb
– Moisture and debris are less likely to contaminate the contacts of a screw base bulb
– Spring contacts are not necessary on screw base bulbs (the spring tension must not only ensure a good contact but it must also hold the bulb securely in the bayonet so there is a compromise)

Oops. What I have copied and pasted from Wikipedia has activated the Which? profanity filter. S******g is the opposite of unscrewing. It’s a crude alternative to bayonet cap lamps.

As I explained above the point about street lights is that they are under far more arduous conditions of vibration and potential corrosion than domestics lights. Experience there is very relevant. They generally have far bigger contact areas than B22d. Find me a modern HID lamp that has a BC cap. They are subject to high current ( up to 19A for a 2kW) for example, and high starting voltage pulses – several kV. Screw caps are suitable for these extreme applications (compared to the domestic environment) so I’d suggest they’ll be OK at home, as most of the rest of the world finds.

Street lights are a different product and use heavier glass and probably different metals/plating. Screw threads jamming is well understood from an engineering perspective. I recommend a trace of high temperature silicone grease to prevent oven lamps jamming.

Wonder how many words would get through were we to do a post on fitting E27 light sockets into a Hen house /storage shed where some excavation of the underlying medium-grade metamorphic rock was needed while warning of the dangers of sharp pointed vegetation?


The lamps are constructed in the same way – I have been associated with a lamp manufacturer and a maintenance company so simply pass on direct experience for the benefit of anyone watching. Make of it what you will. 🙂

Just look at the lamps in your home and you will see that some are plated and some are not. That can make a big difference. I think we had better agree to differ.


At first I disliked the continental screw caps on lamps as they were bulky and made the lamp-holder/shade ring combination complicated. It was my biggest gripe about IKEA when they first opened here. that all their lighting required screw cap lamps.

I had noticed that the light-bulbs in my school and various workplaces had screw caps and presumed that was to prevent pilferage; however, those in the old railway carriages had bayonet caps – but they ran on a different voltage and were fairly dim so not very appealing to pinch.

In the 1980’s, I think, table lamps and standard lamps started to appear with screw cap lamps so it was necessary to have a stock of both types of bulb. The Small Bayonet Cap [SBC] and the Small Edison Screw [SES] cap came along for smaller fittings, wall lights, multi-branch ceiling lights and other lower wattage applications. It was a good way of ensuring that bulbs would not be too hot for the smaller shades. I found that the SES types made a more positive connexion in the small lamp-holders.

Eventually, moving home a few times and replacing light fittings meant that there was little choice as most of the types we liked had the smaller bulbs and required screw caps.

Compared with the bayonet fittings I found the screw caps more secure in the lamp-holder, the lamp-holder was not prone to distortion or damage to the L-shaped openings that held the bayonet pins in place, there was no need to apply pressure against springs in order to fit and remove a bulb, and they do not have projecting pins that can get bent of broken off. I have had more trouble with bayonet caps getting stuck in a lamp-holder or the glass envelope breaking away than with screw cap lamps [necessitating shutting off the power and trying to extricate the parts with long-nosed pliers].

We still have some large ceiling lights that require bayonet cap bulbs but since they now have LED’s bulbs in them the need to change the lamps will be much reduced. I still have a large stock of incandescent bayonet cap lamps, including up to 150W, but I can’t see any further need for them now. I don’t suppose charity shops are allowed to sell them – perhaps the next time a friend of mine does a car boot sale I can hand them over and see if there are any takers.

I have a few 150s too – and a rig to put them in parallel – for rejuvenating capacitors – use the rig as a safe PTC thermistor – start off with a single 25W, then a 40, then 2 x 25, then a 60 – then a 100 – then a 150, then 2, then 3…..

One reason for the use of bayonet-fitting light bulbs is their resistance to vibration – screw cap lamps can loosen on, for example, vehicles, machinery and so in. Another is they allow lamps to be positioned correctly when their orientation in a fitting is important. The railways often used 3-pin bayonet fixings to make pilfering unprofitable – not usable at home. BC lamps make an automatically reliable electrical contact, whereas for screw caps you have to ensure they are fully screwed home.But for most domestic applications I’d suggest screw caps are marginally better.

Regarding contact reliability, surely a sprung holder centre terminal on ES fittings would overcome a lot of such issues with mechanical stop being the ceramic part against the holder. Also, is the ES thread start position not sensibly defined to ensure consistent orientation for bulbs that are not fully rotationally symmetrical (qv Practika/Pentax K lenses)?

Reliable contact does require the cap to be screwed home. The lampholder contact is slightly sprung, but it is possible to insert a lamp without proper contact. I was drawing the distinction between a design assuring full contact assuming a properly-functioning lampholder) and one that does not.

Where lamps require accurate positioning, as for example twin filaments in vehicles, the bayonet design assures this. So do other designs – like a flange support. A screw cap can allow electrical contact without guaranteeing position.

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Andy says:
3 November 2019

I am not convinced that Energizer bayonet fitting (standard ceiling lamp fitting) bulbs last the claimed 15,000 hours. It feels like I am having to replace them rather more frequently than that. 15,000 hours is 625 days at 24 hours per day which is most certainly well above the usage that they get in my house. I have now taken to writing the date that I install them on the neck of the bulb.

After a few years of replacing various sorts of “new” style bulbs quite often, recently they have stopped dying and they also seem to give a better quality of light than they did. I don’t remember buying a new bulb for at least a year. They have become an expensive purchase compared with the old tungsten bulbs that one bought in packs of six for a couple of pounds.

The Chinese import LED bulbs almost always expire when sub-standard electrolytics dry up. More reputable manufacturers use long life/high temperature ones (Matsushita used to be the main manufacturer).

Andy says:
7 December 2019

I had another Energizer bulb fail today. Shop where I bought it from was not in the slightest bit interested and, of course, I do not have the receipt. I have left customer comments with Energizer asking how they will refund me. There appears to be a date stamp on the stem of the bulb suggested it was manufactured in Sept 2018. If this is the case, even if I had used it for 24 hours a day since manufacture, it would not be anywhere near 15,000 hours old.
So, Dear Which: please do an investigation into Energizer bulbs and expose them for the fraud that they are. I certainly will not be buying any more of their bulbs.

Hi Andy – I have a 1521 lumen Energizer bulb that I bought a little over a year ago. There is a number 201809 that could be a manufacturing date of September 2018.

As the equivalent of an old 100W incandescent light bulb it is high power for a LED bulb and the base does get uncomfortably hot, but it has survived so far, possibly because the bulb is well ventilated. I have kept the receipt and packaging just in case. I don’t know how many hours but being in the hall it’s on for hours most days at this time of year.

Though it’s always useful to let manufacturers know about problems with products, and they are sometimes helpful in my experience, your legal rights are against the retailer, not the manufacturer. In the absence of a receipt, some other evidence of purchase such as a credit card statement would suffice. The date stamp might establish the manufacturing date but will not provide evidence of where it was bought from, so you might have to hope that the manufacturer offers goodwill.

I’ve decided to go for Philips GU10 to replace my cheap (Meridian) lamps which nearly all 10 have failed within 7 Months. In addition the cheap lamps use Capacitive droppers instead of proper voltage regulators (Like Philips). This could mean higher energy bills if your smart meter measures Kva instead of Kwh.

Thanks Ian. As far as I know, domestic users pay for kW rather than kVA, unlike commercial users, but that might change. An easy way to check the power factor of lamps is to use a table lamp connected to an inexpensive plug-in energy monitor that displays the power factor (or both kVA and kW). GU10s (as used in downlighter) are harder to check because these cannot be tested using a table lamp.

Power factor should be as close to one as possible (as it is for old fashioned bulbs) and can sometimes be found from the specification. I don’t believe I have any lamps with a capacitive dropper but I guess the PF would be well below 0.5. Capacitive droppers can be reliable but only if you use decent capacitors. It is cheaper to cut corners. 🙁

Ian – I don’t know whether your Meridian lamps are produced by the same company as this one, which looks respectable and produces commercial lighting products: http://www.sld-london.co.uk/files/sld-catalogue.pdf

As the owner of both a GU10 table lamp and a power meter, I can report that a randomly selected LED lamp uses 2W but 10VA. The CFL lamp normally used there used 8W at 16VA.

Thank for the figures. I tested a 5.5W Philips GU10 (bought in 2016 rather than current) and measured 6W and 8VA, so a power factor of about 0.75 compared with 0.2 in your case. (I doubt my meter is accurate at low loads.) The figures for your CFL, giving a PF of about 0.5, seem about right from what I can remember.