Difference between Incandescent and Fluorescent Light Bulbs

Both incandescent and fluorescent light bulbs are time proven elements of lighting fixtures. The two types of bulbs are different in many respects and we will take a closer look at these differences.


Incandescent light bulb
Incandescent light bulb

Incandescent light bulbs produce electric light with a thin filament made of tungsten metal. This type of metal is perfectly suitable for the purpose due to its conducting qualities, and incandescent light bulbs are sometimes referred to as tungsten light bulbs. When tungsten is heated to 2,300 degrees Celsius, it emits white light whose glow creates the illumination.

English engineer Joseph Swan patented the first incandescent light bulb back in 1878, and since then it has become the most popular means of lighting in households all over the world. Incandescent lamps are of two kinds: halogen and conventional. The two types differ in terms of gas filling the lamp and pressure inside the bulb and, as a result, differ slightly in color, efficiency and life of the lamp.

fluorescent lamp bulb
A compact fluorescent lamp bulb

Fluorescent light bulbs are quite common nowadays. They come in a variety of shapes and sizes. The physical process inside a fluorescent bulb starts with the electrodes that send electrical current through the gas in a lamp. This gas is argon with a little bit of mercury added. When the current is switched on, the electrodes heat up, and via the process called thermo-ionic emission, they push gas through one end of the lamp to the other creating an argon arc. Through the subsequent series of processes the white visible light is produced.

The basic principle of operation in a fluorescent bulb
The basic principle of operation in a fluorescent bulb. A: Fluorescent tube, B: Power (+220 volts), C: Starter, D: Switch E: Capacitor, F: Filaments, G: Ballast

Fluorescent light bulbs have become very popular recently in the form of compact fluorescent light (CFL). More households in the United States and all over the world prefer using CFL instead of incandescent light bulbs.

Comparison chart

Incandescent light bulbs Fluorescent light bulbs
Luminous efficiency is low Luminous efficiency is high
Have a shorter life Have a longer life
Limited number of colors More colors are available
Energy consuming Energy saving
Are totally safe Are thought to cause health issues
Cheap More expensive
Incandescent vs Fluorescent Light Bulbs
Incandescent (right) and fluorescent light bulbs side to side

Incandescent light bulbs vs Fluorescent light bulbs

What is the difference between incandescent and fluorescent light bulbs?

  • A luminous efficacy, to put it simply, is the amount of Lumens per watt in the lighting unit. The luminous efficacy of incandescent light bulbs is relatively low. The heating process involved in the incandescent bulb transforms only up to ten percent of utilized electricity into actual light, while the rest is transformed into heat. On the other hand, fluorescent light bulbs provide much more Lumens per watt, making this type of lamp much more efficient than incandescent bulbs, while providing a comparable light output.
  • An incandescent light bulb’s longevity is 2,000 hours on average. A fluorescent light bulb’s longevity is significantly higher – from 6000 to 15000 hours. Due to a physical process that is utilized in incandescent bulbs, they are sensitive to voltage changes. If voltage supply is set up properly, an incandescent light bulb may function twice as long. The life of a fluorescent light bulb, on the other hand, may be shorter if the bulb is switched on and off frequently.
  • There was a time when fluorescent bulbs were only available in  a rough, greenish color which was somewhat unpleasant to the eye. They were extensively used in hospitals, warehouses and other facilities where the light has to be switched on constantly. Nowadays they come in much greater variety of colors than incandescent light bulbs. While incandescent bulbs can only be of a warm reddish tone, fluorescent bulbs can be of almost any color of the specter.
  • Incandescent light bulbs are significantly more energy-consuming than fluorescent light bulbs. A fluorescent bulb utilizes around 75 percent less energy than an incandescent one.
  • Incandescent light bulbs are not harmful for health. Fluorescent light bulbs, on the other hand, are subject to some controversy regarding their safety. Studies have shown that CFLs of the recent generation, if broken indoors, release into the air 20 times the maximum concentration of mercury recommended for safety. There is a special protocol one needs to check should a fluorescent bulb get broken.
  • Incandescent light bulbs are cheap and can be bought in the United States for as low as 5 dollars for a 4-pack. On the other hand, fluorescent light bulbs cost around $10 to $15 for a 4-pack. The reason for the difference in price is that fluorescent fixtures require the current regulation via ballast. Buying fluorescent light fixtures is a long-term investment, and in the long run they can save money due to the greater longevity of the bulbs.


In this video you can see an analysis that explains the differences between incandescent light bulbs and fluorescent light bulbs: