Why Are My LED Lights Not Bright?

The time for thinking about it is over. And the time to act is here.

Therefore, you have taken the plunge into replacing your traditional bulbs with energy-saving and long-lasting LEDs.

However, just like any other electrical device, you are running into some issues with the technology that is supposed to last a long time. So what’s going wrong?

Understand that, more often than not, an LED gives issues due to improper use. LEDs are sensitive to several things that you need to be careful about.

LED bulbs can lose their brightness due to premature aging, bad internal components like a capacitor or LED arrays, or the common cause of loose wiring. Heavy load appliances on the circuit can also cause that LED lights are dim.

Why Are LED Bulbs Very Dim?

Firstly, you need to validate your crazy hypothesis of whether your bulb is actually dimmer than you remember, or are you just seeing things?

A light meter will help you by accurately measuring the lumens or foot candles to know exactly how dim your bulb has become, but it is unnecessary.

A natural cause for LED losing brightness is simply life span: the bulb has reached the End of Life.

This somber sounding event is when the LED has reached its life rating down to L-70 or L-50 luminosity, emitting only 70 or 50% of its original light output.

However, this might not be the case necessarily. Here is a recent example from one of my LED fixtures.

dim LED light bulb in the fixture

As you can see in the picture, there are two originally, identically bright LED bulbs. However, one works at its full brightness, and the second LED has a much lower lumen output.

I have decided to take it off and open the bulb to investigate why this particular LED light has become very dim.

Here is what I have seen when I have opened the bulb.

opened LED bulb with faulty diodes

Clearly, you can see that one out of eight LED chips has gone bust. I also suspect the LED chip next to the damaged one is faulty.

I have decided to investigate it further and see if any of the mother-plate components are damaged, but as you can see below, they all seem to be fine.

internal components of LED light bulb

I must admit I haven’t gone into testing each of them and just did a brief visual check and concluded that the faulty LED diode in the array was the cause of the light problem.

In this little example, I have only shared one reason why LED lights are not bright, but there are many other issues to keep in mind, so keep reading.

LED Light Dims Then Suddenly Brightens

Talking about a more specific problem, you may have run into an issue whereby the LED bulbs in your home may dim for a moment and then return to full brightness.

One scenario is when LED lights dim in a single room or phase. This is where surge wattage comes into play.

Usually, when you have high-load appliances like washers, dryers, or microwaves in the same circuit as your bulb, and the appliances are switched on, you will experience surge wattage.

Appliances draw a high surge power to turn on than to continue running. So the sudden change in voltage affects your bulb’s overall brightness, which then corrects itself within a few seconds.

Another scenario might be that LED lights are dimming throughout your house or office? A less frequent but more serious cause for across-the-house dimming could be a loose or corroded neutral wire in the electrical panel.

It’s essential to get loose wiring fixed immediately to prevent arching and a short circuit, leading to fatal house fires.

In the rarest setting, if house lights are dimming and returning to brightness after a big storm, then check with your neighbors. Suppose they are also experiencing the same thing. In that case, the service cable running from your electrical panel to the meter and further on to the transformer is at fault.

These are called brownouts, as opposed to complete power failure called a blackout. Call your city or power company and they will remedy the loose or disconnected wiring.

New LED Bulb Is Not Bright Enough

new bulb

First of all, you need to know that for LED light bulbs, you need to look for Lumen output per Watt as opposed to Wattage rating (as is the norm for traditional light bulbs). This will go far in helping you buy an adequately bright LED in the first place.

The higher the lumen rating, the brighter the LED bulb will be.

Secondly, if you’ve bought LED lights and used them in your existing fixture, connecting them to your old dimmer switch, incompatibility might be at play.

Your LEDs need to be dimmable, and the dimmer needs to be compatible with a dimmable LED; otherwise, you will run into LED dimming issues.

If your new bulb is stuck at low brightness with dimmer, a component within the dimmer has likely died due to the nature of LED dimming, i.e., high frequency on/off cycles.

This might have led to your LED light being stuck at a low brightness setting, as the dimmer switch is now only outputting lower voltage.

So your bulb might be okay but needs a new compatible dimmer switch.

Finally, older houses may have wires that are no longer able to handle the load of today’s high powered and numerous electronics around the house.

A couple of new LED lights might have been the last straw leading to the visible symptoms of underlying poor wiring.

Too much current running through old wiring to power a home or office can lead to low overall voltage, and your brand new bulbs might end up being dim.

Why Do LEDs Dim Over Time?

You bought an LED bulb that was working alright but has visibly dimmed over a short time.

If you are into tinkering with your electronics safely, of course, then opening the LED bulb up might educate you on at least one likely reason, just like I have shown you earlier.

You have to look out for at least one swollen or bulged capacitor on the circuit board or the damaged LED chip.

If the LED light has other capacitors, they will be intact. Thus current will be running through only the remaining working capacitors. Reducing the voltage being supplied to the emitters and dimming the light visibly.

Another simple reason could be a tight and non-ventilated fixture that traps heat, and prematurely and rapidly reduces the LEDs lifespan.

LEDs typically operate efficiently in junction temperature range between 40°C and 60°C (104°F – 140°F), and otherwise love cool environments.

Moving to the final cause of dimming bulbs, leads us to the external and internal drivers that power the LED bulbs.

Some LED applications, such as flood lights, allow you to connect an external power supply to the LED. In this case, you have to be knowledgeable about current, voltage, and power ratings.

Using a driver or power supply whose power rating does not match that of the LED will result in dim light output. You should look at the power factor to see the driver’s efficiency.

What Can you do to Fix the Dim Bulb?

A simple fix to a common problem of dim LED lights included in ceiling fan fixtures is as follows:

Using the remote switch, simply press and hold the light button down on your remote. The light will start to get brighter! Definitely try it.

Sometimes, a single bad LED emitter like in my example can result in the overall luminosity dropping or flickering to occur.

If you’re experienced with handling electrical DIY, a simple fix for this is to short the bad LED out or remove it from the circuit board. The following even flow of current in all working LEDs will fix any dimming issues.

You also need to understand that by shorting the faulty diode within the bulb, it will get naturally dimmer because that one diode was contributing to the total brightness.

So the light output will still be lower than initially.

Here is a video on how to do it.

Note that, although this quick fix will work, the voltage within the bulb changes and now needs to be distributed between fewer diodes.

LEDs within the bulb will have to deal with higher voltage per diode. Long term exposure will damage them, so eventually, they will all become faulty.

To fix dimming from circuit overload, split your heavy load appliances and move them to a different circuit from the bulbs. Most heavy load appliances should anyway be on their own dedicated circuits.

Finally, try to buy an all-in-one power supply with the LEDs, so you don’t run into mismatched power ratings between the two.

Final Words

At this point, you must have a fair idea of what might have caused your LED to dim randomly, or flicker, or both.

I would like to know about your experience after installing new LEDs.

  • Are your new LED light bulbs dimmer than they should be?
  • Did your existing LED lights reduce in brightness earlier than expected?
  • Did you try the method above to brighten your ceiling fan lights?

18 thoughts on “Why Are My LED Lights Not Bright?”

  1. Converted ceiling led fixture into a plug in lamp. Led doesn’t get bright. I’ve done this before with regular bulb fixture with no issue.

    Reply
    • Hi Phyliss,

      Strange. The only issue that comes onto my mind is that the wattage of the LED fixtures is lower. The fixture is not able to provide the adequate power to the LED bulb. Potentially the converter you have used in a fixture can be reducing that.

      Eugen

      Reply
  2. I installed a new dimmable led light fixture as well as a new dimmer switch – the light is extremely dim and will not get brighter. Any suggestions?

    Thanks!

    Reply
    • Hi Brent,

      The first thing that comes onto my mind is the incompatibility between the bulb and the dimmer. What can also be an issue is the base light output of the bulb. Say if you used to have bulb that was emitting 800 lm and your new bulb emits only 500 lm, it will seem dimmer.

      Eugen

      Reply
  3. I replaced incandescent bulbs (2 of them) in my garage with LEDs. Now, when I turn on the switch, they light up normal, but after a minute or so, they dim to like half power. Also, when they are switched off, they stay off for about a minute, then power back up half-way. If I move my switch half-way between on/off, then the lights stay off

    Reply
    • Hi Clarence,

      Thanks for reaching out, it seems like the switch is the culprit. It almost looks like the flipping mechanism is damaged.

      Sorry cant be much more of the help, but as you can imagine its hard to help through the internet without seeing the issue.

      Eugen

      Reply
  4. I have two LED shop light on same circuit. They’re hooked up to 3way switches. They are about two weeks old when ( while on) they popped off. Now when turn on they are very dim. Verily can see them lit. They are in a pole building and this time of year in cold conditions.
    Can you give me an idea what’s wrong . They worked fine up until this point.

    Reply
    • Hi John,

      Most likely the capacitor inside the LED light has popped. So you should replace the light and if you can claim warranty.

      Eugen

      Reply
  5. I have a 5 bulb chandelier with a non-dimmable switch. Following some halogen bulb failures, I decided to replace all 5 with LEDS – which happened to be dimmable, but I didn’t change the switch. When I replaced 4 bulbs all five were bright (as expected) but on replacing the 5th halogen bulb with an LED bulb, all 5 went dim! putting back one halogen bulb restored them all to full brightness. Can’t get my head round why this should happen. Any ideas?

    Reply
    • Hi Margo,

      Quite often when you replace CFLs with LEDs and leave the ballast in the fixture it can mess up with the LEDs that don’t require it. I would need a bit more info to advise.

      Eugen

      Reply
  6. We have outdoor path lights that must be on all night for safety reasons. We replaced the fittings on the bollards and put LEDS in, got about 3 years out of them and them one by one they started failing, ie no light at all. Fair enough. We replaced all 13 at the same time with exactly the same Philips bulb. Now after 6-8 months 11 out of 13 have dimmed. I’ve tested and it’s definitely the bulb but what could be the cause?

    Regards
    Terry

    Reply
    • It is hard to tell like that, is it possible that something has changed in the circuit that it has become unstable or overloaded? This can damage bulbs.

      What about the fixtures themselves, are they enclosed?

      Eugen

      Reply
    • Hi Ben,

      Often manufacturers are saving the cost on the production by putting cheap components inside. This is quite often with many of them. Say TV manufacturers will put cheap half-charged batteries into the remote because it is not what they sell. The same applies here, the manufacturer doesn’t sell the light, but it sells the mirror meaning that to reduce production cost they will save on bulbs. So what I would do is to take the bulb out and try it in a different fixture, if the issue is the same, then bulbs are damaged.

      Eugen

      Reply
  7. I’ve got 2 LED recessed lights in my kitchen that worked great for months and then both went very dim at the same time. I turned them off for a while and tried again – both still running very dim. I removed the bulbs and replaced them a few days later, and now they’re not coming on at all. Any theories?

    Reply
    • Hi Mark,

      Seems like you just had bad luck with the light. Seems like there is a manufacturer fault, but you wouldn’t know unless you open the bulbs themselves to investigate and look for any bulged capacitors or burned diodes as I did with my bulb in the example.

      Eugen

      Reply

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