Do Incandescent Bulbs Flicker? (Why + How To Stop It!)

Whenever you notice rapid or quick changes in the brightness level of the light then it’s the sign that is telling you that the light source is flickering. And who would like to work or stay in a place where the lighting level keeps on changing quickly, right? If you have an incandescent light bulb then you might be wondering, do incandescent light bulbs flicker?

Incandescent light bulbs do flicker because of faulty wiring connections, bad filament, etc. However, the light filament in incandescent light bulbs does not get cooled quickly enough during the ‘off’ time when the voltage changes in the AC power line and so they generally do not cause flicker problems.

Let’s dive in deeper and talk more about if it’s normal for new incandescent light bulbs to flicker, why do incandescent bulbs flicker, how fast do they flicker, and also how to stop this flickering issue. Without any further ado let’s get started!

Do Incandescent Bulbs Flicker (Why + How To Stop It!)

Is It Normal For New Incandescent Light Bulbs To Flicker?

Incandescent light bulbs do flicker but if you are finding flickering issues in a new incandescent light bulb then it is not normal.

There can be some issues that are causing the flickering problem in the incandescent light bulb. Let’s have a look at why incandescent light bulbs flicker.

Why Do Incandescent Light Bulbs Flicker?

Flickering in a light bulb can be defined as the changes in the intensity level of the illumination. Now the main reason the flickering happen is because of the Voltage drops in the distribution lines.

One thing to note is that flickering will be present in all light sources that run on AC (Alternating Current).

Whether it is an incandescent bulb, a fluorescent bulb, or an LED, you will notice some amount of flicker in all. The reason behind this is our power grid runs on the AC which cycles at 50 Hz or 60 Hz depending on the country we live in.

In case you don’t know, Hz (Hertz) is nothing but the number of cycles that happen per second.

The fast voltage change feed into the light bulbs and as a result causes the flickering problem. Here are some other possible reasons why incandescent bulbs flicker:

#1. Bulb Is Faulty

If your incandescent light bulb is faulty or burned out then it can also cause flickering issues. Some of the reasons that can cause flickering issues in the light bulbs are:

  • Worn-out Receptacles
  • Bad Filament
  • Improper Wiring Connections

Generally, these kinds of problems occur as your light bulb ages. 

#2. Loose Connection

If you haven’t placed the light bulb properly in its socket then it can also cause the flickering issue. And if the incandescent light bulb is loosely connected to the power socket, then it will keep on disconnecting from its power supply periodically.

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If you notice that even slight touch to the lamp is causing the light bulb to flicker then it is likely that the bulb is loosely connected and hence you need to fix it.

#3. A Problem in the Light Bulb Fixture

Sometimes your fixture can also be the problem why your incandescent light bulb flicker. So to check whether it is really an issue or not you can remove the light bulb and try it in a different fixture.

If in the new fixture the bulb is working properly without any flickering issue then it may indicate that the first fixture is causing the problem. 

Actually, with time the sockets can also get worn out and the metal parts are no longer able to make proper secure connections.

In such a case, you will have to either repair the fixture or even replace it.

#4. Wiring Issue

If a fixture is not causing the flickering issue in your light bulb, then the faulty wiring of your home can also be the reason for flickering.

In case you notice that many of your home’s lightings are flickering specifically when you run any other electrical appliance, then it may be because of an overloaded circuit.

If the wiring of your home is quite old, then it may not be able to keep up with the increased power demand. And in such a case, you might have to contact an electrician to replace the service panel.

Flickering is usually a problem with the lightings in which ballast are used such as fluorescent lights.

By the way, have you ever wondered whether or not fluorescent light bulbs get hot? If interested, I highly recommend you to check out my complete article on do fluorescent bulbs get hot where I explain it in detail.

In the case of the incandescent light bulbs, the heating and cooling cycle of its filament is slow as compared to the electrical cycle and thus adding a buffer to the flicker.

And because of that, the bulb doesn’t modulate intensity to the uncomfortable levels of the flicker.

How Fast Do Incandescent Lights Flicker?

When an AC power runs through an incandescent light bulb, its filament quickly gets heated up and also gets cooled down from the AC frequency cycle. As a result, you will notice a flicker rate of 2 times the AC frequency.

So in general, an incandescent light bulb will flicker at 100/120 Hz

How To Stop My Incandescent Light Bulbs From Flickering?

First, you need to identify what is causing the incandescent bulb to flicker. I already shared with you some of the possible reasons why light bulbs flicker.

So you can reference that and see what is causing the light bulb to flicker in your particular case.

Bulb Worn Out or FaultyIt’s Time to Fix or Replace it
Loose ConnectionTighten It
Problematic FixtureFix it or Replace it
Wiring FaultFix the Wiring

If you think that your bulb is old and has worn out then it’s time to replace it. If it is new but faulty and if you know how to fix the problem then also you can do it.

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Now if you identified the problem as a loose connection then you just need to fix it and your problem will be solved in most cases. 

So to fix the loose connection, just tighten it. In order to tighten the bulb, first, make sure that the bulb is cool enough to touch and turn the socket clockwise.

Remember, don’t try to force the tightening. Once you properly tighten the bulb to the socket, the receiver of the bulb will be properly connected with the lamp’s power supply.

If you find that the fixture is the main cause of the flickering issue then you can either replace it or fix it if possible.

Lastly, if you find that the wiring of your home is causing the flickering problem in the incandescent bulb then you need to fix it first. You may also need to get in touch with a professional electrician to solve this issue.


So in short, although not so usual, but incandescent light bulbs do flicker. I have already shared with you all the reasons why it occurs and also how to stop the flickering problem. Hope this post has helped to get your problem solved. Thanks!

Now, before you go I want to ask you, do you use light socket adapters? Are you sure that they are totally safe? If interested, I highly encourage you to check out my detailed article about are light socket adapters safe here.

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