The light from Fluorescent tubes and bulbs are caused by an electric current conducted through inert gases.
Though fluorescent use only around 30% of the same energy that incandescent bulbs use, they provide the same amount of light (about 30 – 110 lumens per watt).
They also last about 10 times longer (7,000-24,000 hours)
Fluorescent lights require a ballast to regulate operating current and provide a high start-up voltage. Electronic ballasts outperform standard and improved electromagnetic ballasts by operating at a very high frequency that eliminates flicker and noise. Electronic ballasts also are more energy-efficient.
There are 2 general types of fluorescent light bulbs:
Compact Fluorescent Fixtures
CFLs combine the energy efficiency of fluorescent lighting with the convenience and popularity of incandescent fixtures. CFLs fit most fixtures designed for incandescent bulbs and use about 75% less energy.
Although CFLs cost a bit more than comparable incandescent bulbs, they last 6–15 times as long (6,000–15,000 hours).
CFLs are most efficient and cost effective where lights are on for long periods of time. They aren’t recommended for areas such as pantries and closets where lights are turned on for short periods of times, because the payback is slower. They are also ideal for hard-to-reach areas since they do not need to be changed often.
CFLs are available in a variety of styles or shapes, and each is designed for a specific purpose. The size or total surface area of the tube(s) determines how much light it produces. Many models are dimmable, as indicated on the package, and are and compatible with other lighting controls.
Common types of CFLs include:
FLUORESCENT TUBE AND CIRCLINE LIGHTING
Fluorescent tubes -- the second most popular type of fluorescent lighting -- are more energy efficient than standard incandescent lightbulbs.
The traditional tube-type fluorescent lights are usually identified as T12 or T8 (12/8 or 8/8 of an inch tube diameter, respectively). They are installed in dedicated fixtures with built-in ballasts. The two most common types are 40-watt, 4-foot (1.2-meter) lamps, and 75-watt, 8-foot (2.4-meter) lamps.
Tubular fluorescent fixtures and bulbs are often used for ambient lighting in large indoor areas. In these areas, their low brightness creates less direct glare than incandescent bulbs.
Circular, tube-type fluorescent lightbulbs are called circline bulbs. They are commonly used for portable task lighting.
CLEANUP AND DISPOSAL
CFL bulbs contain a small amount of mercury, which is essential in conducting electricity in this type of bulb. Mercury can be hazardous to the environment, so it is important to recycle your used CFL bulbs rather than throw them away. Many hardware and retail stores will recycle used CFL bulbs -- contact a local retailer to find out.
If a CFL bulb breaks, it can release some of its mercury as vapor. Therefore, you must follow specific cleanup steps to avoid coming in contact with the mercury. See the EPA recommendations for cleanup steps.