CFLs (Compact Fluorescent Lamps) are energy-saving bulbs consisting of a fluorescent tube which has been made into a shape the same size as a traditional incandescent light bulb.
CFL Bulbs contain gases which are given an electric current, generating UV light which then excites the gasses. A phosphorous layer is then produced on the inside which glows, giving off light. There is very little heating involved.
Compact fluorescent light bulbs come in various shapes, such as:
CFL light bulbs come in many variations of white. They are most commonly classed as "Cool White" or "Warm White", which describes the colour temperature of the light that the bulb emits. Colour temperature is a measurement of the light output, given in Kelvin (K). The higher the value, the cooler the white. For example, 5000K would be cool white lighting.
The base of the bulb depicts what fitting it pairs with. CFL lamps usually have a push and twist bayonet or Edison screw base, both of which are available in various sizes.
Fluorescent bulbs are designed to be more energy efficient than incandescent or halogen bulbs. They have a very low energy consumption which also saves money on electricity bills, over time. CFL bulbs have a much longer lifetime too, of up to approximately 10 years. The lifetime of the light bulb will be stated in hours.
Although CFLs do not use the same technology as incandescent bulbs, they are often given a comparable wattage value, providing an easy comparison to the equivalent wattage.