Electricity a Light Bulb Use

How Much Electricity Does a Light Bulb Use?

Ian Mutuli
Updated on
Ian Mutuli

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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Electric bulbs have been a fundamental part of our lives for over a century, illuminating our homes, workplaces, and public spaces. With the global shift towards sustainability and electric vehicles rising and renewable energy sources, it's crucial to understand how much electricity these bulbs consume. Bringing us to the question, "how much electricity does a light bulb use?" Our article explores how much electricity a light bulb uses and the factors influencing its efficiency.

What Are the Different Types of Light Bulbs and Their Energy Consumption Rates?

Several light bulbs are available today, each with unique characteristics and applications. The electricity consumption of each bulb type can vary based on its wattage measured in kilowatt hour, which indicates the amount of electrical power the bulb consumes. Here's a general overview of how much energy different types of bulbs use:

1. Incandescent Bulbs

These are the traditional and oldest type of light bulbs.

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They pass an electric current through a filament, which glows and produces light. Incandescent lights are inexpensive but highly inefficient, generating more heat than light.

Electricity consumption:

The wattage of an incandescent light bulb ranges from 40W to 150W or more, depending on the desired brightness level.

2. Compact Fluorescent Lamps (CFLs)

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Compact Fluorescent Lamps are energy-saving bulbs that use fluorescent technology. They consist of a twisted or folded glass tube that contains mercury vapour and a phosphor coating. When electricity flows through the fluorescent tube, it excites the mercury vapour, producing ultraviolet (UV) light. The UV light then interacts with the phosphor coating, creating visible light. CFLs are more energy-efficient than incandescent bulbs and have a longer lifespan. They are mostly used in bathrooms as they are the best light bulbs for bathroom illumination.

Electricity Consumption

The wattage of CFL light bulbs ranges from approximately 5W to 30W, depending on the desired light output. To replace the light output of a traditional 60W incandescent bulb, a CFL bulb usually consumes around 13W to 15W.

3. Light-Emitting Diodes (LEDs)

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Light-Emitting Diodes have gained significant popularity due to their remarkable energy efficiency and longevity. These bulbs pass an electrical current through a semiconductor material emitting light. LEDs are highly efficient, generate little heat, and last much longer than other bulb types. They are available in various shapes, sizes, and colours. You can install the best LED grow lights for your indoor gardening.

Electricity Consumption

The wattage of LED bulbs ranges from approximately 3W to 20W or more. An LED bulb generally consumes around 5W to 10W to replace the light output of a traditional 40W incandescent bulb.

4. Halogen Bulbs

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These bulbs resemble incandescent bulbs but contain a halogen gas (such as iodine or bromine) that allows the filament to operate at higher temperatures. This increases the bulb's efficiency and lifespan compared to traditional incandescent bulbs. Halogens are commonly used in applications requiring precise lighting, such as task lighting and automotive headlights.

Electricity Consumption

The wattage of halogen bulbs ranges from 25 watts (W) for small bulbs to 500 watts (W) or more for larger and more powerful bulbs. For example, a standard halogen bulb that emits light equivalent to that of a traditional 60W incandescent bulb consumes around 43 watts (W) to 72 watts (W) of electricity.

5. High-Intensity Discharge (HID) Bulbs

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HID bulbs produce light by passing an electrical current through a gas or vapour. They are commonly used in outdoor and industrial settings, such as street lighting and sports arenas. HID bulbs include metal halide, high-pressure sodium, and mercury vapour bulbs.

Electricity Consumption

  1. Metal Halide (MH) bulbs range in wattage from 70 watts (W) to several hundred watts, such as 400W or 1000W. The electricity consumption of metal halide bulbs can be relatively high compared to other lighting options.
  2. High-Pressure Sodium (HPS) bulbs: They typically range from 35 watts (W) to 1000 watts (W), with higher wattages used for larger areas. HPS bulbs have better energy efficiency compared to metal halide bulbs.
  3. Mercury Vapor Bulbs usually range from 50 watts (W) to 1000 watts (W).

6. Fluorescent Tubes

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Fluorescent tubes are long, tubular bulbs that use the same technology as CFLs but in a different form factor. They are commonly used in commercial spaces, offices, and larger indoor areas that require general illumination.

Electricity Consumption

Common wattages and lengths of fluorescent tubes include:

  1. 18-inch (0.45 meters) tubes: These are often used in small fixtures like under-cabinet lighting and some desk lamps. They consume around 5 watts (W) to 15 watts (W) of electricity.
  2. 24-inch (0.6 meters) tubes: Commonly used in residential and commercial settings, they consume about 10 watts (W) to 20 watts (W).
  3. 36-inch (0.9 meters) tubes: These are frequently found in offices, schools, and other indoor spaces. They consume around 15 watts (W) to 40 watts (W).
  4. 48-inch (1.2 meters) tubes: One of the most common sizes used in various applications, they consume about 28 watts (W) to 55 watts (W).
  5. 60-inch (1.5 meters) tubes: Often used in industrial or large commercial settings, they consume around 32 watts (W) to 86 watts (W).

7. Xenon Bulbs

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Xenon bulbs are a type of HID bulb that uses xenon gas to produce light. They are often used in high-intensity automotive headlights, providing a bright and crisp white light.

Electricity Consumption

Xenon HID bulbs come in various wattages, such as 25 watts (W), 35 watts (W), or 55 watts (W) per bulb. For example, a standard automotive xenon HID bulb consumes around 35 watts (W) per bulb. If you have a pair of headlights (two bulbs), the total electricity consumption would be 70 watts (W) when you use both headlights.

8. Smart Bulbs

Smart bulbs are LED bulbs that can be controlled remotely through a smartphone app or integrated with voice-controlled smart home systems. They offer features like dimming, color-changing capabilities, and scheduling options.

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Electricity Consumption

The wattage of smart LED bulbs ranges from around 5 watts (W) to 15 watts (W) for standard household lighting while still producing the same amount of light as higher-wattage incandescent bulbs.

Which Type of Light Bulb Is Most Energy Efficient?

The most energy-efficient light bulb currently available is the Light-Emitting Diode (LED) bulb. LED bulbs use less energy than traditional incandescent bulbs and other energy-saving bulbs, such as compact fluorescent lamps (CFLs). LED bulbs are highly efficient in converting electrical energy into light, resulting in less wasted energy in the form of heat. They are also among the best bedroom mood lighting bulbs available.

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LED bulbs can save up to 80% or more energy than incandescent bulbs. They also have a much longer lifespan, typically 25,000 to 50,000 hours or even more, while incandescent light bulbs typically last around 1,000 hours. Although LED bulbs are more expensive up front, their energy savings and long lifespan make them more cost-effective in the long run.

LED light bulbs are available in various color temperatures and brightness levels, making them suitable for various applications, from available homes to commercial and outdoor lighting. They also contain no mercury, a notable advantage over CFL bulbs.

Factors Affecting Energy Consumption of Light Bulbs

While wattage is a crucial indicator of energy consumption, it's essential to consider other factors that influence the overall efficiency of an electric bulb:

1. Lumens

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Lumens measure the brightness of a bulb, indicating how much light it emits. Two bulbs with the same wattage can have different lumen outputs, affecting energy efficiency. You can maximize energy savings without compromising brightness by choosing a bulb with higher lumens per watt (lm/W) ratio.

2. Usage

The duration and frequency of bulb usage significantly impact energy consumption. Turning off unnecessary lights is a simple yet effective way to conserve energy. Consider utilizing motion sensors or timers to automate the process and reduce unnecessary energy usage.

3. Bulb Lifespan

The longer a bulb lasts, the less frequently it needs to be replaced. LED bulbs, known for their longevity, can provide reliable illumination for 20,000 to 50,000 hours, surpassing traditional incandescent or CFL bulbs. Investing in bulbs with extended lifespans can lead to substantial energy and cost savings over time.

4. Dimmers and Controls

Dimming systems and smart controls allow users to adjust the brightness of their bulbs. By lowering the light output, energy consumption can be further reduced. However, choosing dimmers and controls specifically designed for LED bulbs is crucial to avoid compatibility issues.

How to Reduce the Cost of Running Light Bulbs

  1. Switch to LED bulbs: LED bulbs use less electricity to produce the same amount of light and have a longer lifespan. Although LED bulbs may have a higher upfront cost, they save money in the long run due to their energy efficiency.
  2. Choose the right bulb wattage: Selecting the appropriate wattage for your light bulbs can help save energy and reduce costs. Use lower-wattage bulbs where adequate lighting is sufficient.
  3. Utilize natural light: Make the most of natural daylight by opening curtains or blinds during the day. This reduces the need for artificial lighting and significantly lowers energy consumption.
  4. Use dimmer switches: You can adjust the brightness of your lights with dimmer switches. By dimming the lights when full brightness is not required, you can reduce energy usage and extend the lifespan of your bulbs.
  5. Implement motion sensors or timers: They can automatically turn off lights when they are not in use or when there is no movement in the area. This prevents lights from being left on accidentally and helps save energy.
  6. Turn off lights when leaving a room: Encourage everyone in your household or workspace to turn off lights when leaving a room. This simple habit can lead to significant energy savings over time.
  7. Use energy-efficient fixtures: Besides energy-efficient bulbs, consider using fixtures designed to maximize light output while minimizing energy consumption. Look for fixtures with high energy efficiency ratings.
  8. Maintain cleanliness: Dust and dirt on light fixtures can reduce the amount of light they emit. Regularly clean your light bulbs and fixtures to ensure optimal performance.
  9. Consider lighting automation systems: Advanced lighting automation systems can provide additional energy-saving features, such as scheduling lights to turn on and off at specific times or adjusting brightness levels based on occupancy.
  10. Monitor energy usage: Keep track of your energy usage and monitor any changes in consumption. This can help identify areas where you can optimize lighting efficiency and reduce electricity usage.


Electric bulbs have evolved significantly in energy efficiency thanks to technological advancements. The shift from incandescent bulbs to CFLs and LEDs has significantly reduced electricity consumption while providing high-quality lighting. CFLs and LEDs offer substantial energy savings, lasting longer and consuming far less power than their predecessors. By understanding the wattage, lumens, usage patterns, and lifespan of electric bulbs, individuals and businesses can make informed decisions to minimize their energy consumption and contribute to a greener future.

Ian Mutuli

About the author

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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