Does A Burn-Out Bulb Use Electricity?

Lights are essential. There are multiple lights in our houses, and keeping track of all the lights is impossible. You cannot identify them when they burn out, and they stay like that. Do these lights use electricity? 

A burn-out bulb still uses electricity when turned on but will not produce light. Incandescent and halogen light bulbs do not use electricity after a burn-out as the path of electricity flow is broken after the filament burns out. But fluorescent and LED lights use electricity after burning out. 

When you cannot keep track of the burnt-out lights, it stays like that in the socket. This article discusses the possibility of electricity usage by a burnt-out light and what happens if you leave it like that in the socket.

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Understanding how light bulbs work and the role of filament 

There are multiple types of bulbs:

  • Incandescent bulbs
  • Halogen bulbs
  • LED bulbs
  • CFL bulbs

Different bulbs work in different ways. 

A light bulb emits light from a thin filament inside a glass or metallic lamp. 

Light emission combines some visible and invisible components that produce white light. 

Maximum bulbs have a metal filament that heats when the electric current passes through them. 

The heat makes the filament emit light as it cools down and releases energy in photons.

However, not all bulbs use filaments. 

Let’s talk about these bulbs and understand how they work differently. 

Incandescent lights 

Incandescent bulbs emit light through a thin metal filament when it receives electricity and heats it until it glows to produce light. 

The filament is present inside a glass or metallic lamp. 

The glass bulb or enclosure prevents the oxygen in the air from entering the hot filament. 

The vacuum won’t create without the glass, and the filament will overheat and oxidize within a few moments.

The filament is tungsten because it has a high melting point. 

The filament inside the bulb reaches temperatures up to 4,500°F. 

Once it makes electricity through the tungsten filament, the bulb will go down to another wire out of the bulb through the metal part at the socket’s side. 

It will then reach the lamp or the fixture and out of the neutral wire. 

The system is simple yet elegant and works great in giving light. 

The bulb is also compatible with alternating and direct currents. 

LED bulbs

LED bulbs are a new type of light in high demand. 

The diodes in LED bulbs are semiconductors that light up with the help of voltage. 

LED lights are durable, use 90% less energy than incandescent lights, and have 10 times longer lifespans than incandescent ones. 

LED lights are also energy-efficient and emit high-intensity light with less power.

Unlike incandescent lights, LED lights do not have any filament to burn out. 

Since they use less electricity, they do not get hot. 

They light up by the movement of the electrons in a semiconductor material that lasts longer than the standard transistor. 

Fluorescent lights (CFL)

Fluorescent lights are another new type of light that replaces Edison’s famous incandescent lights. 

These lights contain argon, mercury vapor, and a coating of phosphorus powder housed in a spiral-shaped tube. 

The tube ends have electrodes connected to the circuit conducting electricity. 

When you turn on the light, the current will flow through the electrodes, and the voltage will make the electrons move through the argon to the other side of the tube. 

The energy received from this process will turn the mercury into gas and further increase the energy level of the electrons. 

Once the gas excites, the energy is radiated as photons, producing ultraviolet light. 

This UV light again stimulates a fluorescent coating painted on the spiral tube inside.

When the phosphorus powder in the tube interacts with the invisible light spectrum, it produces white light. 

The lights also have a ballast that produces electricity to pass through the vaporous mixtures and excite the gas molecules. 

In the older fluorescent lights, the ballasts took time to produce enough electricity to excite the gas molecules. 

The new lights have efficient ballasts and need only a few seconds to warm up. 

The CFLs are descendants of the lightsaber-shaped fluorescent bulbs that flicker in the garages and workshops. 

Halogen lights

Halogen lights also use filaments like incandescent lights. 

But the filament here is enclosed inside a smaller quartz envelope.

Since the envelope is close to the filament, it can melt if the envelope is made of glass. 

The gas inside the envelope differs and has gas from the halogen group. These gasses combine with tungsten vapor.

When the temperature is high enough, the halogen gas will combine with the tungsten atoms when they evaporate and redeposit on the filament. 

This process allows the filament to last longer.

The hotter the filament gets, the more light you receive. 

What is the role of a filament?

Incandescent and halogen lights glow up by a product called the filament. 

The filament is a thin wire inside the bulb that produces light once it heats up. 

The filament is made of coils of thin wires called coiled coils.

Due to the filament’s high resistance and the electricity’s heating effect, the filament will glow up and give you light. 

However, some new types of light, like LEDs and CFLs, do not use filaments. 

The science behind burnt-out bulbs and how they affect electricity consumption 

When the bulb is burnt-out, the only science behind it is that the filament inside the bulb has broken. 

Over time, the filament can become weak and thin and evaporates due to the high temperatures it experiences to produce light and break off.

Usually, every bulb has a lifespan. 

After a certain period, the bulb will burn out due to the wear out of the filament. 

But is the science behind a bulb that burns out faster?

Here are some reasons behind a fast burnt-out bulb:

  • The bulbs will burn brighter when your house’s supply voltage is too high. So the bulbs will burn out faster. Test the voltage of the standard outlet with a multimeter or voltage tester. If the result is above 125V, your bulb will burn out faster. 
  • Vibration shakes the filament too much and burns the bulbs faster. Using rough-service bulbs would be ideal as they have heavy-duty filaments that can withstand the vibration better. 
  • When the socket tab remains too far downside, it fails to contact the bulb. The problem is that the bulb doesn’t burn, but the light does not light up. So, people misunderstand this as a burnt-out bulb. 
  • Short circuits in the wiring cause the fixture to go off. It further reduces the resistance, increases the current flow, and suddenly trips the breaker. It further turns off the current flow, and your light burns out suddenly.
  • Using the wrong bulb size can lead to bulb burn-out. If your lamp is rated for 60W, but you use a 120W light bulb, the fixture will make excessive heat, and the bulb light’s lifespan gets shortened. So, it burns out faster.

How do burnt-out bulbs affect energy consumption?

Not all bulbs consume energy after burning out.

Incandescent and halogen lights do not use any electricity after burning out. 

In these lights, the filament is the central part. 

Whenever the current passes through the filament, it heats to a specific temperature to provide light. 

So, if the filament is snapped, current flow will be absent. A burnt-out incandescent and halogen bulb won’t use any electricity. 

In fluorescent lights, you have mercury, argon, and a coating of phosphorus powder. 

When the current flows through the electrodes, the voltage moves through the gas on the other side. 

Energy from the transition turns the mercury into gas. 

The fluorescents also use transformers and ballasts to light up. 

When the light is burnt out, these components still draw current. 

So, these bulbs will still ingest energy despite being burnt out. 

The process is the same in the LED lights. 

The diodes and other parts help in emitting light by using the voltage. 

Despite burning out, the diodes in the LED light will still draw electric current through the circuit. 

Not only do burnt-out bulbs use electricity, but they also consume energy from good bulbs and reduce their lifespan.

So, these good lights will become less efficient and struggle to light up.

That is why you must replace these bulbs as soon as possible. 

Debunking common myths about burning out bulbs and their impact on energy bills 

There are several myths about the burnt-out bulbs around us. So, I am here to debunk these myths and help you with the facts:

Myth 1

The first myth is that the burnt-out bulb socket uses no energy.

It is valid for incandescent and halogen lights but not CFL and LED lights. 

They do not use filaments but other components like mercury and diodes to illuminate. 

So, despite burning out, these components will still use the energy, and current will flow through the socket. 

Myth 2

Many people have a misconception that frequently turning the lights on and off will use more energy.

That is not the truth. 

Keeping them on when necessary and turning them off when not needed helps reduce energy usage. 

When you turn on a light, a small amount of power is used for illumination. 

But the surge is nothing compared to the energy you save after turning off the light. 

Myth 3 

Burnt-out lights reduce circuit load. 

That is not true. 

The circuit load reduces only when you unscrew the light from the socket. 

At that moment, the current flow stops flowing to the socket. 

It is when the circuit load will reduce. 

Examining the difference in electricity consumption between burnt-out bulbs and functioning bulbs

If you don’t know whether a burnt-out bulb consumes energy, differentiate the energy consumption between a burnt-out bulb and a good bulb. 

Mike Bourgeous experimented with it and differentiated the electricity consumption between the functioning and burnt-out bulbs. 

I thought of experimenting too. 

So, I took 2 bulbs per Bourgeous’ experiment – a good one with 26W and a burnt-out one with 9W. 

The initial measurement of a good bulb was 23.5W, and after 10 minutes, it was 22.3W. 

Now, I measured the bad bulb. It had 9.8W in the beginning, which turned out to be 11W after 10 minutes.

So, it is clear that the burnt-out bulb will consume energy around 50% of the functioning bulb. 

Analyzing the cost implications of using burnt-out bulbs over time

Using burnt-out bulbs can significantly impact the cost of energy bills. 

LEDs and CFL bulbs will use energy because of the components they have in them. 

For example, you have a 15-watt typical fluorescent bulb and keep it on for 8 hours daily.

According to the US Department of Energy, a 15-watt fluorescent bulb will use 15 watts or 15/1000 = 0.015 kilowatts per hour.

So, in one year, the burnt-out bulb will use 0.015 kWh x 8 hours x 365 days = 43.5 kWh of energy. 

If the average electricity rate is $0.13 per kWh, the burnt-out bulb will cost around 43.8 kWh x $0.13 per kWh = $5.69. 

On March 7, 2023, the average kWh electricity cost was around 14.96 cents, or $0.1496. So, the cost of the burnt-out bulb will be around $6.5.

Though affordable, it won’t be if you have multiple burnt-out lights. So, always replace the burnt-out bulbs to save the cost. 

So, that is how burnt-out bulbs have an impact on the electricity cost. 

If you have multiple bulbs, the cost implication will be even higher.

Additionally, these burnt-out bulbs will negatively impact the good bulbs by consuming around 50% of the energy from the good bulbs. 

Discussing ways to reduce energy consumption when using light bulbs and replacing burnt-out bulbs

When winter arrives, the nights get longer. So, it is time to keep the lights on longer. 

Additionally, it would be best to think about reducing the energy consumption by the light. 

During the old times, incandescent lights used to consume too much energy. But the recent LEDs and CFLs use 50-70% less energy. 

So, here are some ways to reduce energy consumption:

Use energy-saving bulbs

Replacing the old halogen or incandescent bulbs with the new CFLs and LEDs will save around 60 to 80% of energy. 

These lights cost more but use only 10-20% of energy. So, the cost is worth it. 

LEDs also last longer than standard lights, from 4 to 30 years. 

Reduce the light wattage

Some rooms will have lights so glaring that it becomes an eyesore. 

If the location does not need that much light, it is better to use low-wattage lights. 

The higher the wattage, the more energy it uses. 

Using less-wattage bulbs will consume less amount of energy. 

Install timers and sensors

Motion-controlled lights can turn the light on and off whenever necessary. 

So, they will stop you from keeping the light on when it is unnecessary and save time and money. 

Use individual switches for each light

It is better to have a single switch for a single light.

Each light will have its switch, and you can turn it on and off whenever needed. 

The others you do not need will remain off. 

But if one switch controls multiple lights, the unnecessary lights will also turn on with the necessary ones. 

So this leads to unnecessary energy consumption. 

Keep the lights clean.

Keeping the bulbs clean and maintaining them increases their efficiency. 

Cleaning them makes the function properly and efficiently and increases their lifespan. 

Proper functioning lights will give you enough light with little energy consumption. 

Replace the burnt-out lights.

Unlike incandescent lights, burnt-out CFLs and LEDs consume energy even when burnt out. 

The bulbs can consume around 50% of the energy from the good bulbs. 

As a result, the functioning bulbs struggle to provide you with enough light. 

To replace a burnt-out bulb:

  1. First, turn off the power at the fixture by unplugging the fixture or turning off the power at the circuit breaker. 
  2. Let the bulb cool down. The modern bulbs will take a few seconds to cool down, but the traditional lights will take time. 
  3. Remove the old bulb from the socket and check it closely. If your bulb uses a filament, it will be broken. In that case, you have to replace it. 
  4. Please insert the new bulb into the socket and twist it clockwise. Connect it properly and secure it in place. 
  5. Now, turn on the fixture’s power or the circuit’s power. Turn on the light to see if it is working. 

Environmental impact of leaving burnt-out bulbs in light fixtures

Letting the burnt-out bulbs stay in the fixture does not affect you too much. But it is not considered safe. 

However, removing the burnt-out bulbs from the fixture reduces the circuit breaker’s load. 

Once you remove the burnt-out bulb, it will break a portion of the circuit. 

Usually, when you turn off the switch, you break the circuit and stop the current flow. 

Similarly, removing the burnt-out bulb from the socket stops the current flow and thus saves electricity. 

An empty socket does not produce any electricity. 

There are several environmental impacts of leaving the burnt-out bulb stay in the fixture:

  • Incandescent and halogen lights use a filament to light up. But the CFLs and LEDs use gasses like mercury, argon, phosphorus powder, diodes, etc. Even after burning off, these components will be active and spread in the surrounding environment when they break. 
  • Letting the burnt-out bulbs stay in the fixture means it will keep using the electricity and the energy of other bulbs. Keeping them like that for prolonged periods leads to gas emissions and climate change. 
  • When you keep the burnt-out bulbs in the fixture, you miss out on the prospect of using the new bulbs, which are more energy-efficient than these burnt-out bulbs. As a result, the electricity used by these burnt-out bulbs is more than those used by the new energy-efficient bulbs. 
  • These burnt-out bulbs also consume energy from the other bulbs and reduce their lifespan.
  • Burnt-out bulbs can be anywhere. For example, if they are near some landfills, these bulbs will release toxic mercury and other substances from the bulb, harming the environment and human health.
  • When these toxic substances are released into the environment, the burnt-out bulbs will contribute to light pollution, disrupt the ecosystem, and negatively affect the plants and wildlife.

Impact of burnt-out bulbs on the lifespan of other lights bulbs in the same fixture

Letting the burnt-out bulbs stay in the fixture can affect the other bulbs connected to the same fixture. How? Here’s what I have found out. 

Lights in series 

Letting the burnt-out bulbs stay in the same fixture as the other lights can affect the good ones if they are connected in series. 

We know that in series circuits, all the lights are wired and connected together to each other. 

So, when one light goes out, all the others will be out too.

But, in a parallel circuit, the lights in the same fixture are wired individually. 

So, one burnt-out bulb does not affect the other bulbs in the fixture. 

Therefore, when one light burns out in a series circuit, all the other lights in the series circuit will go off despite being in good condition.

That is why it is recommended to change the burnt-out bulbs immediately. 

Energy consumption

Another reason is energy consumption. 

According to Mark Bourgeous, keeping the burnt-out light in the same fixture with the other good bulbs consumes around 50% of the energy from the good bulbs.

As a result, the shelf life of the functioning bulbs decreases by around 50%. 

These lights also struggle to give you enough light because the burnt-out lights consume half of their energy.

It primarily happens with fluorescent and LED bulbs. 

Exploring the effectiveness of different types of light bulbs in reducing energy consumption

Four types of lights are used: incandescent, halogen, fluorescent, and LED. 

The incandescent lights and the halogen lights have a filament. 

The current needs to first pass through the filament and then produce light.

Additionally, these lights spread too much, requiring diffusers and reflectors. 

That is why they use energy. 

However, Halogen lights are known to use less energy than incandescent, but there is not much difference. 

So, only fluorescent and LED lights help in reducing energy consumption. How? Let’s read it.

Fluorescent lights 

CFL or Compact Fluorescent Lamps use around 70% more energy than incandescent lights because the current flows through a tube filled with mercury and argon. 

CFLs emit a few wavelengths of UV rays in the discharge tube and then convert them into light with phosphor powder.

CFLs use less energy because they need less heat to produce light compared to incandescent lights. 

With less heat, it can produce light better than the incandescents. 

LED lights 

The LED lights use diodes to emit light. 

They produce light in a specific direction, reducing the need for reflectors and diffusers. 

The diodes in LED lights are semiconductors. 

These act as a junction through which the current is filtered and releases light. 

It means the light is emitted directly from the source without any initial powering load, i.e., the filament. 

That is why LED lights produce less energy. 

The role of government policies in promoting energy-efficient lighting and reducing energy waste

The United States Lighting Energy Policy has moved towards increasing efficiency to lower greenhouse gas emissions and electricity bills of the house. 

The US Energy Policy Act 2005 addresses the energy production of the United States with energy efficiency and renewable waste. 

It has further encouraged people to introduce new types of light that do not waste less energy.

The Energy Independence and Security Act (EISA) of 2007 changed the lighting decree by phasing out incandescent lights to use more efficient lights, like fluorescent and LED lights. 

EISA 2007 is an act to increase light efficiency by 25-30%. 

The effort to increase efficiency has also been verified by the Energy Star program and increased efficiency goals in 2011 and 2013. 

Any appliance or light with an Energy Star label is meant to reduce the appliance’s energy efficiency. 

In 2011, incandescent bulbs were the most common and traditional bulbs used in 85% of US houses. 

The bulbs have an efficacy of 10-17 lumens per watt with a lifespan of 750-2,500 hours.

The fluorescent bulbs use 25% less energy and have 10,000 hours of lifetime. 

The government has also encouraged using energy-efficient lights in public buildings through programs. 

For example, the Better Buildings Challenge wants to improve the energy efficiency of the buildings portfolio by 20% over the next 10 years. 

So, all these policies the government has made have helped promote energy-efficient light and energy waste. 

Final thoughts 

Only incandescent and halogen lights do not use electricity after burning out because they use filament. If the filament is broken, the current won’t be utilized. But the technology to emit light is different in CFLs and LEDs. 

So, when they burn out, the inner components, like mercury, argon, and diodes, use electricity. Replace the burnt-out lights because if they are wired in series, all the lights go off. Also, the CFLs consume around 50% of energy from the functioning bulbs. 

For energy consumption reduction, CFLs and LEDs are the best. But replace them when they burn out. To understand the difference between a burnt-out light and a functioning light, try the experiment (by Mike Bourgeous) I have shared in the article. 

Does an empty socket use electricity?

Electricity will run only when it is complete. If a socket is empty and no light is running, the current cannot pass through, and the circuit is incomplete. So, an empty socket does not use any electricity.

Should I leave the socket empty?

If you have a burnt-out or blown bulb, let it stay and turn off the switch or replace it with a new one. Leaving a socket empty leads to electrocution risk because the circuit is open to debris and fire hazard.

Reference: Different types of light Wikipedia,  US Light energy policy Wikipedia

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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