Types of Lighting: Incandescent Bulbs (2024)

There are five basic types of lighting:

  • Incandescent
  • Fluorescent
  • High-intensity discharge
  • LED

Incandescent Bulbs

Thomas Alva Edison invented the incandescent light bulb with reasonable life. Lewis Latimer has perfected it with the use of carbon filament.

The incandescent bulb consists of a sealed glass bulb with a filament inside. When electricity is passed through the filament, the filament gets hot. Depending on the temperature of the filament, radiation is emitted from the filament.

The filament's temperature is very high, generally over 2,000º C, or 3,600º F. In a "standard" 60-, 75-, or 100-Watt bulb, the filament temperature is roughly 2,550º C, or roughly 4,600º F. At high temperatures like this, the thermal radiation from the filament includes a significant amount of visible light.

This principle of obtaining light from heat is called ‘incandescence.” At this high temperature of 2,000º C, about 5 percent of the electrical energy converts into visible light and the rest of it is emitted as heat or infrared radiation.

Instructions : Press play to see how an incandescent light bulb works. (Note: The animation has no audio.)

How an Incandescent Light Bulb Works
Click here to open a text description.

How an Incandescent Light Bulb Works

In an incandescent light bulb, electricity travels up and through the filament, causing it to heat up and glow brightly. To prevent the filament from combusting, all of the oxygen is removed from the bulb.

Let’s now look at several different types of incandescent bulbs.

Standard incandescent bulbs

Standard incandescent bulbs are most common and yet are the most inefficient. Larger wattage bulbs have a higher efficacy (more lumens per Watt) than smaller wattage bulbs.

Instructions: Click the “graph” button below to create a graph comparing Watts and efficiency, and then answer the question below.

Click here to open a text description of the light bulb efficiency activity. This will expand to provide more information.

Comparison of Watts and Efficiency for an Incandescent Bulb

The table below compares the number of Watts of a light bulb to its efficiency (lumens per Watt).

Comparison of Watts and Efficiency for an Incandescent Bulb
Watts (power)25406075100150
Efficiency (lumens per Watt)81214151719

Based on this data, it is clear that as the number of Watts increase, so does the efficiency.

Tungsten halogen bulbs

Tungsten halogen is an incandescent lamp with gases from the halogen family sealed inside the bulb and an inner coating that reflects heat back to the filament. It has similar light output to a regular incandescent bulb, but with less power. Halogens in the gas filling reduce the material losses of the filament caused by evaporation and increase the performance of the lamp.

Types of Lighting: Incandescent Bulbs (1)

A tungsten halogen lamp

Tubular tungsten-halogen bulbs

Tubular tungsten-halogen bulbs are commonly used in “torchiere” floor lamps, which reflect light off of the ceiling, providing more diffused and suitable general lighting.

Although these provide better energy efficiency than the standard A-type bulb, these lamps consume significant amounts of energy (typically drawing 300 to 600 W) and become very hot (a 300-W tubular tungsten-halogen bulb reaches a temperature of about 2600° C compared to about 600° C for a compact fluorescent bulb). Because Tungsten-halogen lamps operate at very high temperatures (high enough to literally fry eggs), they should not be used in fixtures that have paper- or cellulose-lined sockets.

Types of Lighting: Incandescent Bulbs (2)

Tubular tungsten-halogen lamp.

Halogen bulbs

A halogen bulb is often 10 to 20 percent more efficient than an ordinary incandescent bulb of similar voltage, wattage, and life expectancy. Halogen bulbs may also have two to three times as long a lifetime as ordinary bulbs. How much the lifetime and efficiency are improved depends largely on whether a premium fill gas (usually krypton, sometimes xenon) or argon is used. The image below shows a picture taken with an Infrared camera comparing the heat produced by a halogen and a compact fluorescent light bulb. The red and white color zones are extremely hot, and the blue zones are cooler.

Types of Lighting: Incandescent Bulbs (3)

A comparison of heat generated by a Halogen and CFL light bulbs.

Credit: Lawrence Berkeley Laboratory

Reflector Lamps

Reflector Lamps - Light waves from a bulb spread in all directions. The light that goes toward the back is not useful when the light is most needed in the front. Reflector lamps (Type R) are designed to spread light over specific areas.

Reflector lamps have silver coating on the sides, like any mirror, and therefore all the light waves passing through the sides or the back are reflected to the front. Therefore, they are called reflector lamps and are also called floodlighting, spotlighting, and down lighting bulbs.

Instructions: Click the buttons below to see the difference between a regular and reflective lamp light bulb:
(Note: The animations have no audio.)

Normal Bulb

Reflective Bulb

Parabolic aluminized reflector (PAR) lamps

Parabolic aluminized reflector (PAR) lamps (shown in the image below) are also available with halogen technology to operate at 120 volts. A standard 150-W incandescent spotlight can be replaced with a lower wattage halogen lamp, reducing electricity consumption by up to 40 percent.

Types of Lighting: Incandescent Bulbs (4)

A Reflector Lamp (Type R) light bulb.

Types of Lighting:  Incandescent Bulbs (2024)


Types of Lighting: Incandescent Bulbs? ›

There are four popular types of light bulbs: incandescent, compact fluorescent (CFL), halogen, and light-emitting diode (LED).

What are the 4 main types of light bulbs? ›

There are four popular types of light bulbs: incandescent, compact fluorescent (CFL), halogen, and light-emitting diode (LED).

What are 2 examples of incandescent light? ›

Incandescent body: The body which emits light when heated to a very high temperature. Incandescence is the emission of electromagnetic radiation (which includes visible light also) from a hot body as a result of its high temperature or glowing due to heat. Incandescent bodies include light bulb, electric stoves.

What light bulbs are most like incandescent? ›

Energy-efficient LED light bulbs are the new standard for basic light bulbs, and the best ones look and feel just like longer-lasting incandescents.

How do you know if a light bulb is incandescent or not? ›

Additionally, observe the bulb's appearance while off. LEDs typically have a cluster of small diodes, whereas incandescents have a visible filament. When lit, LEDs emit an instant, bright light, while incandescents often have a warm-up time and a softer glow.

Are incandescent bulbs illegal? ›

In April 2022, the U.S. Department of Energy, under the Biden administration, announced the phaseout of energy-wasting lightbulbs, banning the manufacture and sales of common incandescent lightbulbs starting on Aug. 1, 2023.

What are the old fashioned light bulbs called? ›

In homes, bars, and restaurants, you see the old-fashioned light bulbs adorning cozy, inviting spaces and adding a neat vintage vibe to décor. Some call them “Edison” bulbs, since they are designed to show the filament like the original light bulb invented by Thomas Edison.

Why are incandescent light bulbs banned? ›

According to the new guidelines, “general service lamps”—a.k.a. household light bulbs—must now emit a minimum of 45 lumens per watt. Since incandescent bulbs provide only about a third of that, they're effectively banned in the US.

How many types of incandescent lights are there? ›

These are the two main types of incandescent light bulbs: conventional and halogen. The difference between these two types lies in the gas that fills them. Halogen light bulbs contain a special gas that helps keep the bulb clean, slightly improving its efficiency.

Are incandescent bulbs still used today? ›

Is there an incandescent bulb ban? The short answer: yes. Most incandescent and halogen products were phased out in 2023.

What is replacing incandescent light bulbs? ›

LEDs (light-emitting diode)

These diodes are tiny and use up to 80 % less energy than an incandescent bulb, while they have a lifespan of tens of thousands of hours. What is more, LEDs light up instantly and are resistant to shocks and vibrations. Another advantage is that they are available in a wide range of colours.

What light bulb is closest to natural light? ›

Halogen bulbs are a type of incandescent that gives a close approximation of natural daylight, known as "white light." Colors appear sharper under halogen light and the bulbs can be dimmed.

Which bulb burns the brightest? ›

resistance is proportional to the inverse of the power of the bulb in series connection and so the bulb with the lowest wattage(power) will have maximum resistance and it will glow the brightest.

Why do incandescent bulbs look better? ›

A full and balanced spectrum of visible light

Starting with the visible, incandescent light gives off a naturally full and very pure spectrum. As we know, a full spectrum light usually means a high - or in the case of incandescence, nearly perfect - color rendering index, or CRI, score.

Do all incandescent bulbs get hot? ›

The incandescent bulb consists of a sealed glass bulb with a filament inside. When electricity is passed through the filament, the filament gets hot. Depending on the temperature of the filament, radiation is emitted from the filament. The filament's temperature is very high, generally over 2,000º C, or 3,600º F.

Do LED lights get as hot as incandescent? ›

High powered lighting LEDs generate light at a much lower running temperatures than the hot filament used in previous generation bulbs. The hottest outside surface of an LED light bulb is often half the temperature of an equivalent brightness Incandescent or Halogen bulb, and around 20% cooler than CFL bulbs.

What is the most commonly used light bulb? ›

The most common types of light bulb used in homes are 25, 40, 60, 75 and 100 watts. For most rooms, a 60 watt bulb is the standard. A 25 watt bulb gives off low levels of light, where as a 100 watt bulb is very bright.

What are the common types of light bulbs? ›

There are four prominent light bulb types: light-emitting diode (LED), compact fluorescent (CFL), incandescent, and halogen. For a helpful quick-select tool, check out our light bulb size chart!


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