Light Bulbs: Compact Fluorescent Lamp (CFL)



Compact Fluorescent Lamp (CFL)

Primelite continues our look at the different types of light bulbs. From Incandescent to LED, lighting has changed immensely over the past 200+ years. In the past we’ve taken a look at Incandescent Bulbs, Reflector Lamps (Incandescent)Tungsten-Halogen Lamps and Fluorescent Lamps. This week we’ll explore Compact Fluorescent Lamps (CFL).

What is a Compact Fluorescent Lamp.

A compact fluorescent lamp, or CFL, is a fluorescent lamp that was designed to be used as a replacement for incandescent bulbs. Many CFL lamps were designed to fit into light fixtures originally used with incandescent bulbs. These lamps are usually curved or folded ensuring the CFL can fit into existing incandescent fixtures. CFL’s acceptance as an incandescent replacement has been largely due to its lower use of energy and electrical cost savings. CFL’s use up to 70% less power compared to incandescent lamps and over the course of the lamps life are cheaper to light.

CFL styles

Compact Florescent Lamps (CFL) are available in assorted shapes and designs assuring their use in existing incandescent lamp  fixtures.

Similar in construction to fluorescent lamps, the compact florescent lamp is a low pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light.

Mercury-vapor gas discharge lamps are an artificial light source that generates light by sending an electrical discharge through an ionized gas. An electric current in the gas excites the mercury vapor which then produces short-wave ultraviolet light that causes a phosphor coating on the inside of the bulb to glow. The fluorescent lamp converts electrical energy into useful light several times the efficacy of an incandescent bulb with comparable light output.


Like Fluorescent lamps, CFLs use an auxiliary device, a ballast, to regulate the current flow through the lamp. In most cases the CFL ballast is integrated into the lamps base.

While Fluorescent lamps were first developed in the mid to late 1800’s during the experiments leading to the development of the incandescent lamp, the spiral CFL was invented in 1976 by Edward E. Hammer, an engineer for General Electric. Its design was in response to the 1973 oil crisis but was deemed too costly and was shelved. The design was eventually copied and in the mid 1990’s CFLs started to be commercially produced in China. The first successful screw-in CFL was introduced in 1980 by Phillips and is now the standard, and successful, incandescent lamp replacement.

Because of the mercury contained within, CFLs need to be properly disposed or recycled. In the US many home-supply chain stores, as well as many cities and states offer free CFL recycling.

While the compact fluorescent lamp (CFL) has become important  as the replacement for the incandescent bulb, future lighting trends point to its eventual replacement with LED lamps.


Update 04/15/16 – GE to Phase Out CFL Bulbs – General Electric has announce that they are phasing out CFLs and increasing LED production. Source:



Series: Primelite looks at the light bulb:


Wikipedia – Compact Fluorescent Lamp (CFL)

Energy Star – Learn About CFLs

Pictures Sources:

Energy Star – Parts of a CFL