The compact fluorescent lamp is a miniaturized fluorescent tube packaged with a built-in ballast in a standard screw base that can be installed in a conventional socket.
They have a much longer life than incandescent bulbs - usually 7500-10,000 hours, but often as much as to 20,000 hours compared to 750 to 1000 hours for a standard incandescent.
When Choosing a Compact Fluorescent Lamp, these are some considerations:
Size: Some lamps have a size or shape that is not compatible with existing light fixtures.
Warm Up Time: Many lamps do not produce full output until they warm up for a minute or two. This can be a factor on dark stairways when the light switch is turned on immediately before using the stairs. There may not be enough light for safety.
Color: The color of the light from compact fluorescent lamps is not the same as incandescent bulbs. This can cause colors to show up slightly differently.
Dimmers: Compact Fluorescent bulbs are not compatible with the dimmer switches used for incandescents. Special Dimming lamps must be used.
Temperature: Like other fluorescents, operation at cold temperatures (under around 50 degrees F) may cause reduced light output or erratic operation. Some models work fairly well down to about 35 degrees F, others may get noticeably dim below 60 degrees F. The optimum temperature range of a particular lamp may vary with burning position, generally preferring cooler temperatures if operated base-down. Compact fluorescents may also not like excessive heat. Some ballasts are unreliable in ambient temperatures much over 120 degrees F. This is sometimes a problem in enclosed or recessed ceiling fixtures if heat in the fixture builds up.
Compact Fluorescent lamps and an important part of a homes, and a nations energy system. Many state agencies and utilities are so convinced of this that significant rebates are often available.