Difference between Incandescent and Fluorescent

Key difference: Incandescent light bulbs produce light by an electrical current heating up a tungsten wire filament inside a glass bulb. Fluorescent light bulbs heat up mercury vapor to produce light.

Incandescent and fluorescent are both types of light bulbs, which are commonly used today in various lighting applications. Incandescent bulbs are the older and more commonly used ones, but fluorescent bulbs, which are relatively new, are fast replacing the incandescent.

Incandescent light bulbs are the common bulbs that everyone uses in their homes. The bulbs have a very thin filament inside the glass sphere. They produce light by passing an electrical current through the filament. The filament is a very long and very thin metal wire which is made out of tungsten. It is surrounded by an inert gas, to prevent any ignitions of oxygen or other gases due to large temperatures.

Because the filament is so thin, it offers good resistance when the electricity is passed through it. The resistance turns electrical energy into heat. The temperature of a filament can reach up to 3500 K without melting. The heat, in turn, makes the filament white hot. The glow of the filament is the emitted light. Ninety percent of the energy produced by incandescent lighting is heat, while only ten percent of the energy is actually light.

A fluorescent bulb, on the other hand, uses a completely different method to produce light. The bulb is a glass tube coated with phosphor and contains mercury vapor. When electricity is supplied to the bulb, the mercury vapor gets energized. The mercury then starts sending out ultraviolet energy. The phosphor coating absorbs the ultraviolet energy and begins to glow or fluoresce. This is the light that it emits. The fluorescent bulb is commonly in the shape of a long tube, known as a fluorescent lamp. It is now also commonly available in a compact shape, known as the compact fluorescent lamp or CFL.

Incandescent bulbs are famous for their warm yellow light, whereas fluorescent bulbs are criticized for their hard clinical white light. However, as compared to incandescent bulbs, fluorescent bulbs are more expensive, this is mainly because they use only one-quarter to one-third of the energy that incandescent bulbs use.

Also, fluorescent bulbs last longer than incandescent light bulbs. Regular incandescent bulbs last an average of 750 to 1,000 hours before burning out, and long life bulbs may last up to 2,500 hours. However, fluorescent bulbs last 10 to 15 times longer than that, up to 10,000 hours or more. This is turn leads to energy savings, so fluorescent bulbs are more environment-friendly. Still, fluorescent bulbs contain mercury vapor which is classified as a hazardous material, so they should be properly disposed.

Furthermore, fluorescent bulbs are at least four to six times more efficient than incandescent bulbs. For example, a 15-watt fluorescent bulb produces the same amount of light as a 60-watt incandescent bulb.

A detailed comparison between incandescent and fluorescent bulbs:





Light is emitted by heating the filament present in the bulb.

Generate light by sending an electrical discharge through an ionized gas.


Argon, tungsten, filaments

Argon, mercury vapor, tungsten, barium, strontium and calcium oxides.

Operational Life

Up to 2,500 hours. On average 750 to 1,000 hours.

10 to 20 times more than the incandescent bulb. Up to 10,000 hours.


Clear, frosted, decorative

Tanning bulbs, growth bulbs, bilirubin bulbs, germicidal bulbs

Light Production

Produces 15 lumens per watt of input power.

Produces between 50 and 100 lumens per watt.


25 watt, 40 watt, 60 watt, 75 watt, 100 watt, 150 watt

4 watt, 9 watt, 15 watt, 20 watt, 25 watt, 30 watt, 42 watt, 55 watt, 65 watt, 80 watt, 85 watt, 100 watt, 105 watt, 150 watt, 200 watt


Cheaper than fluorescent.

More expensive than incandescent.

Image Courtesy: kozaimodern.com, green-the-world.net

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really, this explains the best i have heard.

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