How CFL Works

Fluorescent light tubes are similar to neon tubes in that their light is a product of gas subject to electricity. A fluorescent tube is filled with argon gas and a trace amount of liquid mercury. When electricity flows through the argon gas, it excites the mercury atoms to produce light. This light would emit dangerous ultra-violet (UV) radiation, but the glass tube is coated with phosphorous to absorb much of the radiation. The phosphorous is the white substance that “clouds” the glass tube.

The primary advantage of fluorescent lights is that they are more energy efficient than incandescent bulbs (up to 75 percent more efficient). Much of the energy used in an incandescent bulb produces heat rather than light. Fluorescent lights also lack the heated filament used to produce light in an incandescent bulb. It is the super-heating of this filament that shortens the life of an incandescent, which means the fluorescent light lasts longer.


Fluorescent lights have three disadvantages: cost, UV radiation and ballasts. Fluorescent lights are more expensive than the traditional incandescent bulbs. They also emit UV radiation, while not harmful to humans in most situations, exposure will fade certain types of art, textiles, furniture finishes and damage other objects. Fluorescent lights also require ballasts to control the surge and amount of electricity in the glass tube. When ballasts go bad, they cause annoying flickering and dimming of lights.

A major obstacle with the use of fluorescent lights in the home is that light fixtures have to accommodate the ballast and tube. This meant that older versions of fluorescent lights could not be used in standard lamps, wall sconces and other fixtures designed for incandescent bulbs. This has partially been solved by the production of compact fluorescent lights (CFLs). The tube in a CFL is spiraled to produce a light that can be used in fixtures designed for incandescent bulbs.

Liquid mercury is a very hazardous material and, because of the trace amount of mercury in fluorescent lights, care is needed in the disposal of the tubes. The Environmental Protection Agency (EPA) recommends that used fluorescent lights be disposed at a proper recycling center. Household hazardous waste sites will typically collect fluorescent lights. If a light tube breaks, place the debris in a sealed, plastic bag and thoroughly vacuum all pieces and empty into the sealed plastic bag.

Source: Ehow