Compact fluorescent lamp

Compact fluorescent lamp

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A compact fluorescent lamp (CFL), also called compact fluorescent light, energy-saving light, and compact fluorescent tube, is a fluorescent lamp
Fluorescent lamp
A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...

 designed to replace an incandescent lamp
Incandescent light bulb
The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process...

; some types fit into light fixture
Light fixture
A light fixture, light fitting, or luminaire is an electrical device used to create artificial light and/or illumination, by use of an electric lamp...

s formerly used for incandescent lamps. The lamps use a tube which is curved or folded to fit into the space of an incandescent bulb, and a compact electronic ballast in the base of the lamp.

Compared to general-service incandescent lamps giving the same amount of visible light
Luminous flux
In photometry, luminous flux or luminous power is the measure of the perceived power of light. It differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of...

, CFLs use less power (typically one fifth) and have a longer rated life (six to ten times average). In most countries, a CFL has a higher purchase price than an incandescent lamp, but can save over five times its purchase price in electricity costs over the lamp's lifetime. Like all fluorescent lamps, CFLs contain mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

, which complicates their disposal. In many countries, governments have established recycling schemes for CFLs and glass generally.

CFLs radiate a light spectrum that is different from that of incandescent lamps. Improved phosphor
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...

 formulations have improved the perceived colour of the light emitted by CFLs, such that some sources rate the best "soft white" CFLs as subjectively similar in colour to standard incandescent lamps.

History



The parent to the modern fluorescent lamp was invented in the late 1890s by Peter Cooper Hewitt
Peter Cooper Hewitt
Peter Cooper Hewitt was an American electrical engineer and inventor, who invented the first mercury-vapor lamp in 1901. Hewitt was issued U.S. patent #682692 on September 17, 1901. In 1903, Hewitt created an improved version that possessed higher colour qualities which eventually found widespread...

. The Cooper Hewitt lamps were used for photographic studios and industries.

Edmund Germer
Edmund Germer
Edmund Germer was a German inventor recognized as the father of the fluorescent lamp. He applied for a patent with Friedrich Meyer and Hans J. Spanner on December 10, 1926, which led to...

, Friedrich Meyer, and Hans Spanner patented a high-pressure vapor lamp in 1927. George Inman later teamed with General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 to create a practical fluorescent lamp, sold in 1938 and patented in 1941. Circular and U-shaped lamps were devised to reduce the length of fluorescent light fixtures. The first fluorescent bulb and fixture were displayed to the general public at the 1939 New York World's Fair
1939 New York World's Fair
The 1939–40 New York World's Fair, which covered the of Flushing Meadows-Corona Park , was the second largest American world's fair of all time, exceeded only by St. Louis's Louisiana Purchase Exposition of 1904. Many countries around the world participated in it, and over 44 million people...

.

The helical (three-dimensional spiral) CFL was invented in 1976 by Edward Hammer, an engineer with General Electric, in response to the 1973 oil crisis
1973 oil crisis
The 1973 oil crisis started in October 1973, when the members of Organization of Arab Petroleum Exporting Countries or the OAPEC proclaimed an oil embargo. This was "in response to the U.S. decision to re-supply the Israeli military" during the Yom Kippur war. It lasted until March 1974. With the...

. Although the design met its goals, and it would have cost GE about US$25-million to build new factories to produce the lamps, the invention was shelved. The design eventually was copied by others. In 1995, helical lamps, manufactured in China, became commercially available; their sales have steadily increased.

In 1980, Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

 introduced its model SL, which was a screw-in lamp with integral ballast. The lamp used a folded T4 tube, stable tri-color phosphors, and a mercury amalgam
Amalgam (chemistry)
An amalgam is a substance formed by the reaction of mercury with another metal. Almost all metals can form amalgams with mercury, notable exceptions being iron and platinum. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore.The...

. This was the first successful screw-in replacement for an incandescent lamp. In 1985 Osram
Osram
Osram, founded 1919, is part of the industry sector of Siemens AG and one of the two leading lighting manufacturers in the world. The name is derived from osmium and Wolfram , as both these elements were commonly used for lighting filaments at the time the company was founded...

 started selling its model EL lamp, which was the first CFL to include an electronic ballast.

Development of fluorescent lamps that could fit in the same volume as comparable incandescent lamps required the development of new, high-efficacy phosphors that could withstand more power per unit area than the phosphors used in older, larger fluorescent tubes.

Construction



The most important technical advance has been the replacement of electromagnetic ballast
Electrical ballast
An electrical ballast is a device intended to limit the amount of current in an electric circuit. A familiar and widely used example is the inductive ballast used in fluorescent lamps, to limit the current through the tube, which would otherwise rise to destructive levels due to the tube's...

s with electronic ballasts; this has removed most of the flickering and slow starting traditionally associated with fluorescent lighting.

There are two types of CFLs: integrated and non-integrated lamps. Integrated lamps combine a tube, an electronic ballast and either an Edison screw
Edison screw
The Edison screw fitting is a system of connectors used for light bulbs, developed by Thomas Edison and licensed starting in 1909 under the Mazda trademark. Most have a right-hand threading, so that it goes in when turned clockwise and comes out when turned counterclockwise, like a hardware screw...

 or a bayonet fitting
Bayonet mount
A bayonet mount or bayonet connector is a fastening mechanism consisting of a male side with one or more pins, and a female receptor with matching L slots and spring to keep the two parts locked together....

 in a single unit. These lamps allow consumers to replace incandescent lamps easily with CFLs. Integrated CFLs work well in many standard incandescent light fixtures, reducing the cost of converting to fluorescent. Special 3-way models and dimmable models with standard bases are available.

Non-integrated CFLs have the ballast permanently installed in the luminaire, and only the lamp bulb is usually changed at its end of life. Since the ballasts are placed in the light fixture they are larger and last longer compared to the integrated ones, and they don't need to be replaced when the bulb reaches its end-of-life. Non-integrated CFL housings can be both more expensive and sophisticated. They have two types of tubes: a bi-pin tube designed for a conventional ballast, and a quad-pin tube designed for an electronic ballast or a conventional ballast with an external starter. A bi-pin tube contains an integrated starter which obviates the need for external heating pins but causes incompatibility with electronic ballasts.

Components


CFLs have two main components: a gas-filled tube (also called bulb or burner) and a magnetic or electronic ballast. For their principles of operation, see Fluorescent lamp
Fluorescent lamp
A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...

.

Standard shapes of CFL tube are single-turn double helix, double-turn, triple-turn, quad-turn, circular, and butterfly.

Electronic ballasts contain a small circuit board with rectifier
Rectifier
A rectifier is an electrical device that converts alternating current , which periodically reverses direction, to direct current , which flows in only one direction. The process is known as rectification...

s, a filter capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...

 and usually two switching transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

s. The incoming 50-60 Hz AC current is first rectified to DC, then converted to high frequency AC by the transistors, connected as a resonant series DC to AC inverter
Inverter (electrical)
An inverter is an electrical device that converts direct current to alternating current ; the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits....

. The resulting high frequency, around 40 kHz or higher, is applied to the lamp tube. Since the resonant converter tends to stabilize lamp current (and light produced) over a range of input voltages, standard CFLs do not respond well in dimming applications and special lamps are required for dimming service. CFLs that flicker when they start have magnetic ballasts; CFLs with electronic ballasts are now much more common.

CFL power sources


CFLs are produced for both alternating current
Alternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

 (AC) and direct current
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

 (DC) input. DC CFLs are popular for use in recreational vehicle
Recreational vehicle
Recreational vehicle or RV is, in North America, the usual term for a Motor vehicle or trailer equipped with living space and amenities found in a home.-Features:...

s and off-the-grid
Off-the-grid
The term off-the-grid or off-grid refers to living in a self-sufficient manner without reliance on one or more public utilities....

 housing. There are various aid agency-led initiatives in developing countries to replace kerosene lanterns
Kerosene lamp
The kerosene lamp is a type of lighting device that uses kerosene as a fuel. This article refers to kerosene lamps that have a wick and a tall glass chimney. Kerosene lanterns that have a wick and a glass globe are related to kerosene lamps and are included here as well...

 (with their associated health hazards) with DC CFLs (with car batteries
Car battery
An automotive battery is a type of rechargeable battery that supplies electric energy to an automobile. Usually this refers to an SLI battery to power the starter motor, the lights, and the ignition system of a vehicle’s engine...

 and small solar panel
Photovoltaic module
A solar panel is a packaged, connected assembly of solar cells, also known as photovoltaic cells...

s or wind generators).
CFLs can also be operated with solar power
Solar power
Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...

ed street light
Street light
A street light, lamppost, street lamp, light standard, or lamp standard is a raised source of light on the edge of a road or walkway, which is turned on or lit at a certain time every night. Modern lamps may also have light-sensitive photocells to turn them on at dusk, off at dawn, or activate...

s, using solar panels located on the top or sides of a pole and light fixtures that are specially wired to use the lamps.

Spectrum of light


CFLs emit light from a mix of phosphor
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...

s inside the bulb, each emitting one band of color. Modern phosphor designs balance the emitted light color, energy efficiency, and cost. Every extra phosphor added to the coating mix decreases efficiency and increases cost. Good quality consumer CFLs use three or four phosphors to achieve a "white" light with a color rendering index (CRI) of about 80, where the maximum 100 represents the appearance of colors under daylight or a black-body (depending on the correlated color temperature).


Color temperature
Color temperature
Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of...

 can be indicated in kelvin
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

s or mireds (1 million divided by the color temperature in kelvins). The color temperature of a light source is the temperature of a black body
Black body
A black body is an idealized physical body that absorbs all incident electromagnetic radiation. Because of this perfect absorptivity at all wavelengths, a black body is also the best possible emitter of thermal radiation, which it radiates incandescently in a characteristic, continuous spectrum...

 that has the same chromaticity
Chromaticity
Chromaticity is an objective specification of the quality of a color regardless of its luminance, that is, as determined by its hue and colorfulness ....

 (i.e. color) of the light source. A notional temperature, the correlated color temperature, the temperature of a black body which emits light of a hue which to human color perception most closely matches the light from the lamp, is assigned.

As color temperature increases, the color changes from red to yellow to white to blue. Color names associated with a particular color temperature are not standardized for modern CFLs and other tri-phosphor lamps like they were for the older-style halophosphate fluorescent lamps. There are variations and inconsistencies between manufacturers. For example, Sylvania's Daylight CFLs have a color temperature of 3,500 K, while most other lamps called daylight have color temperatures of at least 5,000 K.
Name Color temperature
Color temperature
Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of...

(K) (Mired)
Warm/soft white ≤ 3,000 ≥ 333
(Bright) white 3,500 286
Cool white 4,000 250
Daylight ≥ 5,000 ≤ 200


Colored CFLs are also produced, less commonly:
  • Red, green, orange, blue, and pink, primarily for novelty purposes
  • Blue for phototherapy
    Light therapy
    Light therapy or phototherapy consists of exposure to daylight or to specific wavelengths of light using lasers, light-emitting diodes, fluorescent lamps, dichroic lamps or very bright, full-spectrum light, usually controlled with various devices...

  • Yellow, for outdoor lighting, because it does not attract insects
  • Black light
    Black light
    A black light, also referred to as a UV light, ultraviolet light, or Wood's lamp, is a lamp that emits ultraviolet radiation in the long-wave range, and little visible light...

     (UV
    Ultraviolet
    Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

     light) for special effect
    Special effect
    The illusions used in the film, television, theatre, or entertainment industries to simulate the imagined events in a story are traditionally called special effects ....

    s

Black light CFLs, with UVA generating phosphor, are much more efficient than incandescent black light lamps.

Lifespan


The rated life of a CFL ranges from 8 to 15 times that of incandescents. CFLs typically have a rated lifespan
Service life
A product's service life is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be 'serviceable' or supported by its manufacturer....

 of 6,000 to 15,000 hours, whereas incandescent lamps are usually manufactured to have a lifespan of 750 hours or 1,000 hours.

The lifetime of any lamp depends on many factors, including operating voltage, manufacturing defects, exposure to voltage spike
Voltage spike
In electrical engineering, spikes are fast, short duration electrical transients in voltage , current , or transferred energy in an electrical circuit....

s, mechanical shock
Shock (mechanics)
A mechanical or physical shock is a sudden acceleration or deceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation....

, frequency of cycling on and off, lamp orientation, and ambient operating temperature, among other factors. The life of a CFL is significantly shorter if it is turned on and off frequently. In the case of a 5-minute on/off cycle the lifespan of a CFL can be reduced to "close to that of incandescent light bulbs". The U.S. Energy Star program suggests that fluorescent lamps be left on when leaving a room for less than 15 minutes to mitigate this problem.

CFLs produce less light later in their lives than when they are new. The light output decay is exponential, with the fastest losses being soon after the lamp is first used. By the end of their lives, CFLs can be expected to produce 70–80% of their original light output.

The response of the human eye to light is logarithmic
Logarithmic scale
A logarithmic scale is a scale of measurement using the logarithm of a physical quantity instead of the quantity itself.A simple example is a chart whose vertical axis increments are labeled 1, 10, 100, 1000, instead of 1, 2, 3, 4...

 (a photographic "f-stop"
F-number
In optics, the f-number of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter...

 reduction represents a halving in actual light, but is subjectively quite a small change). A 20–30% reduction over many thousands of hours represents a change of about half an f-stop. So, presuming the illumination provided by the lamp was ample at the beginning of its life, such a difference will be compensated for by the eyes, for most purposes.

Energy efficiency



CFLs uses 3–4 times less power than incandescent lamps of equivalent brightness.
50%–70% of the world's total lighting market sales are incandescent.
Replacing all inefficient lighting with CFLs would save 409 terawatt hours (TWh) per year, 2.3% of the world's electricity consumption. In the US, it is estimated that replacing all the incandescents would save 80 TWh yearly.
Electrical power equivalents for differing lamps
Electrical power consumption
Watts (W)
Minimum light output
lumens (lm)
Compact fluorescent Incandescent
9–13 40 450
13–15 60 800
18–25 75 1,100
23–30 100 1,600
30–52 150 2,600

Heating and cooling


If a building's indoor incandescent lamps are replaced by CFLs, the heat produced due to lighting is significantly reduced. In warm climates or in office or industrial buildings where air conditioning is often required, CFLs reduce the load on the cooling system
Air conditioning
An air conditioner is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. The cooling is done using a simple refrigeration cycle...

 when compared to the use of incandescent lamps, resulting in savings in electricity in addition to the energy efficiency savings of using CFLs instead of incandescent lamps. However in cooler climates in which buildings require heating, the heating system
Central heating
A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC system.Central heating differs from local heating in that the heat generation...

 need to replace the reduced heat from lighting fixtures. While the CFLs are still saving electricity, total greenhouse gas emissions may increase in certain scenarios, such as the operation of a natural gas furnace to replace the unintended heating from CFLs running on low-GHG electricity. In Winnipeg
Winnipeg
Winnipeg is the capital and largest city of Manitoba, Canada, and is the primary municipality of the Winnipeg Capital Region, with more than half of Manitoba's population. It is located near the longitudinal centre of North America, at the confluence of the Red and Assiniboine Rivers .The name...

, Canada, it is estimated that CFLs will only generate 17% savings in energy compared to incandescent bulbs, as opposed to the 75% savings that can be expected without heating or cooling considerations.

Luminous efficacy


Because the eye's sensitivity changes with the wavelength, the output of lamps is commonly measured in lumens
Lumen (unit)
The lumen is the SI derived unit of luminous flux, a measure of the total "amount" of visible light emitted by a source. Luminous flux differs from power in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light, while radiant flux...

, a measure of the power of light perceived by the human eye. The luminous efficacy
Luminous efficacy
Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power. Depending on context, the power can be either the radiant flux of the source's output, or it can be the total electric power consumed by the source.Which sense of the term is...

 of lamps is the number of lumens produced for each watt of electrical power used. A theoretical, 100%-efficient, electric light source producing light only at the wavelength to which the human eye is most sensitive would produce 680 lumens per watt.

The luminous efficacy
Luminous efficacy
Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power. Depending on context, the power can be either the radiant flux of the source's output, or it can be the total electric power consumed by the source.Which sense of the term is...

 of a typical CFL is 50–70 lumens per watt (lm/W) and that of a typical incandescent lamp is . Compared to a theoretical 100%-efficient lamp (680 lm/W), these lamps have lighting efficiency ranges of 9–11% for CFLs and 1.9–2.6%, for incandescents.

Cost


While the purchase price of a CFL is typically 3–10 times greater than that of an equivalent incandescent lamp, a CFL lasts 6–15 times longer and uses 3–4 times less energy. A U.S. article stated "A household that invested $90 in changing 30 fixtures to CFLs would save $440 to $1,500 over the five-year life of the bulbs, depending on your cost of electricity. Look at your utility bill and imagine a 12% discount to estimate the savings."

CFLs are extremely cost-effective in commercial buildings when used to replace incandescent lamps. Using average U.S. commercial electricity and gas rates for 2006, a 2008 article found that replacing each 75 W incandescent lamp with a CFL resulted in yearly savings of $22 in energy usage, reduced HVAC
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...

 cost, and reduced labour to change lamps. The incremental capital investment of $2 per fixture is typically paid back in about one month. Savings are greater and payback periods shorter in regions with higher electric rates and, to a lesser extent, also in regions with higher than U.S. average cooling requirements.

The current price of CFLs reflects the manufacturing of nearly all CFLs in China, where labour costs less. In September 2010, the Winchester, Virginia
Winchester, Virginia
Winchester is an independent city located in the northwestern portion of the Commonwealth of Virginia in the USA. The city's population was 26,203 according to the 2010 Census...

 General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 plant closed, leaving Osram Sylvania
Osram Sylvania
Osram Sylvania Inc. is the North American operation of lighting manufacturer Osram GmbH, which is owned by Siemens AG. It was established in January 1993, with the acquisition of GTE’s Sylvania lighting division by Osram GmbH....

 and the tiny American Light Bulb Manufacturing Inc. the last companies to make standard incandescent bulbs in the United States. At that time, Ellis Yan, whose Chinese company made the majority of CFLs sold in the United States, said he was interested in building a United States factory to make CFL bulbs, but wanted $12.5 million from the U.S. government to do so. General Electric had considered changing one of its bulb plants to make CFLs, but said that even after a $40 million investment in converting a plant, wage differences would mean costs would be 50% higher.

Comparison with alternative technologies


Solid-state lighting
Solid-state lighting
Solid-state lighting refers to a type of lighting that uses semiconductor light-emitting diodes , organic light-emitting diodes , or polymer light-emitting diodes as sources of illumination rather than electrical filaments, plasma , or gas.The term "solid state" refers commonly to light emitted...

 using light-emitting diode
Light-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...

s (LEDs) now fills many specialist niches such as traffic lights. Recent consumer availability of household LED lights now compete with CFLs for high-efficiency house lighting as well. LEDs providing over 200 lm/W
Luminous efficacy
Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power. Depending on context, the power can be either the radiant flux of the source's output, or it can be the total electric power consumed by the source.Which sense of the term is...

 have been demonstrated in laboratory tests and expected lifetimes of around 50,000 hours are typical. The luminous efficacy of available LED lamp
LED lamp
An LED lamp is a solid-state lamp that uses light-emitting diodes as the source of light. The LEDs involved may be conventional semiconductor light-emitting diodes, organic LEDs , or polymer light-emitting diodes devices, although PLED technologies are not currently commercially available.Since...

s does not typically exceed that of CFLs, though there have been LED lamps with 75 lm/W overall luminous efficacy at least since autumn 2009. U.S. Department of Energy (DOE) tests of commercial LED lamps designed to replace incandescent or CFLs showed that average efficacy was still about 30 lm/W in 2008 (tested performance ranged from 4 lm/W to 62 lm/W). Solid-state lighting continues to improve; in June 2011 the 8 products in the A-line bulb configuration that DOE tested ranged from 50 to 97 lumens per watt, with an average of 62 lumens/watt.

General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 discontinued a 2007 development project intended to develop a high-efficiency incandescent bulb with the same lumens per watt as fluorescent lamps. Meanwhile other companies have developed and are selling halogen incandescents that use 70% of the energy of standard incandescents.

Other CFL technologies


Another type of fluorescent lamp is the electrodeless lamp
Electrodeless lamp
An electrodeless lamp is a light source in which the power required to generate light is transferred from outside the lamp envelope to inside via electromagnetic fields, in contrast with a typical electrical lamp that uses electrical connections through the lamp envelope to transfer power...

, known as magnetic induction lamp, radiofluorescent lamp or fluorescent induction lamp. These lamps have no wire conductors penetrating their envelopes, and instead excite mercury vapour using a radio-frequency oscillator. this type of light source was struggling with high cost of production, stability of the products produced by domestic manufacturers in China, establishing an internationally recognized standard and problems with EMC
Electromagnetic compatibility
Electromagnetic compatibility is the branch of electrical sciences which studies the unintentional generation, propagation and reception of electromagnetic energy with reference to the unwanted effects that such energy may induce...

 and RFI
Electromagnetic interference
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...

. Furthermore, induction lighting is excluded from Energy Star standard for 2007 by the EPA.

The cold-cathode fluorescent lamp
Cold cathode
A cold cathode is a cathode used within nixie tubes, gas discharge lamps, discharge tubes, and some types of vacuum tube which is not electrically heated by the circuit to which it is connected...

 (CCFL) is a newer form of CFL. CCFLs use electrodes without a filament. The voltage of CCFLs is about 5 times higher than CFLs, and the current is about 10 times lower. CCFLs have a diameter of about 3 millimeters. CCFLs were initially used for document scanners and also for back-lighting LCD displays, and later manufactured for use as lamps. The efficiency (lumens per watt) is about half that of CFLs. Their advantages are that they are instant-on, like incandescents, they are compatible with timers, photocells, and dimmers, and they have a long life of approximately 50,000 hours. CCFLs are an effective and efficient replacement for lighting that is turned on and off frequently with little extended use (for example, in a bathroom or closet).

A few manufacturers make CFL bulbs with mogul Edison screw bases intended to replace 250- and 400-watt metal halide lamp
Metal halide lamp
Metal-halide lamps, a member of the high-intensity discharge family of lamps, produce high light output for their size, making them a compact, powerful, and efficient light source. By adding rare earth metal salts to the mercury vapor lamp, improved luminous efficacy and light color is obtained...

s, claiming a 50% energy reduction; these lamps require rewiring of the lamp fixtures to bypass the lamp ballast.

Starting time


Incandescents reach full brightness a fraction of a second after being switched on, although some models take several seconds to reach their rated luminance. , CFLs turn on within a second, but many still take time to warm up to full brightness. The light color may be slightly different immediately after being turned on. Some CFLs are marketed as "instant on" and have no noticeable warm-up period, but others can take up to a minute to reach full brightness, or longer in very cold temperatures. Some that use a mercury amalgam
Amalgam (chemistry)
An amalgam is a substance formed by the reaction of mercury with another metal. Almost all metals can form amalgams with mercury, notable exceptions being iron and platinum. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore.The...

 can take up to three minutes to reach full output. This and the shorter life of CFLs when turned on and off for short periods may make CFLs less suitable for applications such as motion-activated lighting.

Hybrid CFL


In November 2010 hybrid CFLs, with instant full brightness with no warm-up delay, became available.
These lamps combine a halogen lamp with a CFL. The halogen lamp lights immediately, and is switched off once the CFL has reached full brightness.

Human health



The cost effectiveness of battery-powered CFLs allows aid agencies to support initiatives to replace kerosene lamp
Kerosene lamp
The kerosene lamp is a type of lighting device that uses kerosene as a fuel. This article refers to kerosene lamps that have a wick and a tall glass chimney. Kerosene lanterns that have a wick and a glass globe are related to kerosene lamps and are included here as well...

s, whose fumes cause chronic lung disorders in typical homes and workplaces in developing nations.

According to the European Commission Scientific Committee on Emerging and Newly Identified Health Risks
Scientific Committee on Emerging and Newly Identified Health Risks
The Scientific Committee on Emerging and Newly Identified Health Risks is one of the independent scientific committees managed by the Directorate-General for Health and Consumer Protection of the European Commission, which provide scientific advice to the Commission on issues related to consumer...

 (SCENIHR) in 2008, the only property of compact fluorescent lamps that could pose an added health risk is the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 and blue light emitted. The worst that can happen is that this radiation could aggravate symptoms in people who already suffer rare skin conditions that make them exceptionally sensitive to light. They also stated that more research is needed to establish whether compact fluorescent lamps constitute any higher risk than incandescent lamps.

If individuals are exposed to the light produced by some single-envelope compact fluorescent lamps for long periods of time at distances of less than 20 cm, it could lead to ultraviolet exposures approaching the current workplace limit set to protect workers from skin and retinal damage.

The UV radiation received from CFLs is too small to contribute to skin cancer and the use of double-envelope CFLs "largely or entirely" mitigates any other risks.

Mercury content


CFLs, like all fluorescent lamps, contain mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

 as vapor inside the glass tubing. Most CFLs contain 3–5 mg per bulb, with the bulbs labeled "eco-friendly" containing as little as 1 mg. Because mercury is poisonous
Mercury poisoning
Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...

, even these small amounts are a concern for landfill
Landfill
A landfill site , is a site for the disposal of waste materials by burial and is the oldest form of waste treatment...

s and waste incinerators where the mercury from lamps may be released and contribute to air and water pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...

. In the U.S., lighting manufacturer members of the National Electrical Manufacturers Association
National Electrical Manufacturers Association
is the association of electrical and medical imaging equipment manufacturers. Founded in 1926 and headquartered near Washington, D.C., its approximately manufacture products used in the generation, transmission, distribution, control, and end use of electricity. These products are used in utility,...

 (NEMA) have voluntarily capped the amount of mercury used in CFLs. In the EU the same cap is required by the RoHS law.

In areas with coal-fired power stations, the use of CFLs saves on mercury emissions when compared to the use of incandescent bulbs. This is due to the reduced electrical power demand, reducing in turn the amount of mercury released by coal as it is burned. In July 2008 the U.S. EPA published a data sheet stating that the net system emission of mercury for CFL lighting was lower than for incandescent lighting of comparable lumen output. This was based on the average rate of mercury emission for U.S. electricity production and average estimated escape of mercury from a CFL put into a landfill. Coal-fired plants also emit other heavy metals, sulphur, and carbon dioxide.
In the United States, the U.S. Environmental Protection Agency estimated that if all 270 million compact fluorescent lamps sold in 2007 were sent to landfill sites, that this would represent around 0.13 metric tons, or 0.1% of all U.S. emissions of mercury (around 104 metric tons that year).

The EPA updated their mercury comparison graph in November 2010. The graph assumes that CFLs last an average of 8000 hours regardless of manufacturer and premature breakage. In areas where coal is not used to produce energy, the content emissions would be less than the power plant emissions for both types of bulb.

Broken and discarded lamps



Health and environmental concerns about mercury have prompted many jurisdictions to require spent lamps to be properly disposed or recycled rather than being included in the general waste stream sent to landfills. It is unlawful to dispose of fluorescent bulbs as universal waste in the states of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

, Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...

, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

, Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...

, Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

, and Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...

. In the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

, CFLs are one of many products subject to the WEEE
Waste Electrical and Electronic Equipment Directive
The Waste Electrical and Electronic Equipment Directive is the European Community directive 2002/96/EC on waste electrical and electronic equipment which, together with the RoHS Directive 2002/95/EC, became European Law in February 2003, setting collection, recycling and recovery targets for all...

 recycling scheme. The retail price
Price
-Definition:In ordinary usage, price is the quantity of payment or compensation given by one party to another in return for goods or services.In modern economies, prices are generally expressed in units of some form of currency...

 includes an amount to pay for recycling, and manufacturers and importers have an obligation to collect and recycle CFLs. Safe disposal requires storing the bulbs unbroken until they can be processed. In the U.S., The Home Depot
The Home Depot
The Home Depot is an American retailer of home improvement and construction products and services.The Home Depot operates 2,248 big-box format stores across the United States , Canada , Mexico and China, with a 12-store chain...

 is the first retailer to make CFL recycling options widely available.

Special handling instructions for breakage are currently not printed on the packaging of household CFL bulbs in many countries. The amount of mercury released by one bulb can temporarily exceed U.S. federal guidelines for chronic exposure. Chronic however, implies that the exposure continues constantly over a long period of time and the Maine DEP study noted that it remains unclear what the health risks are from short-term exposure to low levels of elemental mercury. The Maine DEP study also confirmed that, despite following EPA best-practice cleanup guidelines on broken CFLs, researchers were unable to remove mercury from carpet, and agitation of the carpet — such as by young children playing — created localized concentrations as high as 0.025 mg/m3 in air close to the carpet, even weeks after the initial breakage.

The U.S. Environmental Protection Agency (EPA) has published best practices for cleanup of broken CFLs, as well as ways to avoid breakage, on its web site. It recommends airing out the room and carefully disposing of broken pieces in a jar. A Maine Department of Environmental Protection (DEP) study of 2008 comparing clean-up methods warns that using plastic bags to store broken CFL bulbs is dangerous because vapors well above safe levels continue to leach from the bags. The EPA and the Maine DEP now recommend a sealed glass jar as the best repository for a broken bulb.

According to the Northwest Compact Fluorescent Lamp Recycling Project, because household users in the U.S. Northwest have the option of disposing of these products in the same way they dispose of other solid waste, in Oregon "a large majority of household CFLs are going to municipal solid waste". They also note the EPA's estimates for the percentage of fluorescent lamps' total mercury released when they are disposed of in the following ways: municipal waste landfill 3.2%, recycling 3%, municipal waste incineration 17.55% and hazardous waste disposal 0.2%.

Mercury poisoning of Chinese factory workers


In the past decade, hundreds of Chinese factory workers who manufacture CFLs for export to first world countries were being poisoned and hospitalized because of mercury exposure. Examples include workers at the Nanhai Feiyang lighting factory in Foshan
Foshan
Foshan is a city in central Guangdong province in southern China. The prefectural area under the city's jurisdiction over an area of about 3,840 km² and a population of 5.4 million of which 1.1 million reside in the city proper ....

, where 68 out of 72 were so badly poisoned that they required hospitalization. At another CFL factory in Jinzhou
Jinzhou
Jinzhou , is a prefecture-level city of Liaoning province, China. It is a geographically strategic city located in the "Liaoxi Corridor" , which connects land transportation between North China and Northeast China. Jinzhou is China's northernmost seaport and the coastal economic center of West...

, 121 out of 123 employees were found to have excessive mercury levels, with one employee's mercury level 150 times the accepted standard.

Recycling


The first step of processing CFLs involves crushing the bulbs in a machine that uses negative pressure ventilation and a mercury-absorbing filter or cold trap
Cold trap
In vacuum applications, a cold trap is a device that condenses all vapors except the permanent gases into a liquid or solid. The most common objective is to prevent vapors from a vacuum pump from contaminating the experiment or sample of interest. Cold traps also refer to the application of cooled...

 to contain mercury vapor. Many municipalities are purchasing such machines. The crushed glass and metal is stored in drums, ready for shipping to recycling factories.

Greenhouse gases


In some places, such as Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

 and British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, central heating
Central heating
A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC system.Central heating differs from local heating in that the heat generation...

 for homes is provided by the burning of natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

, whereas electricity is primarily provided by hydroelectric or nuclear power
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

. In such areas, heat generated by conventional electric light bulbs significantly reduces the release of greenhouse gases from the natural gas. Ivanco, Karney, and Waher estimate that "If all homes in Quebec were required to switch from (incandescent) bulbs to CFLs, there would be an increase of almost 220,000 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...

s in CO2 emissions in the province, equivalent to the annual emissions from more than 40,000 automobiles."

Design and application issues


The primary objectives of CFL design are high electrical efficiency
Luminous efficacy
Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power. Depending on context, the power can be either the radiant flux of the source's output, or it can be the total electric power consumed by the source.Which sense of the term is...

 and durability. However, there are some other areas of CFL design and operation that are problematic:

Size


CFL light output is roughly proportional to phosphor surface area, and high output CFLs are often larger than their incandescent equivalents. This means that the CFL may not fit well in existing light fixtures.

End of life


In addition to the wear-out failure modes common to all fluorescent lamps, the electronic ballast may fail, since it has a number of component parts. Ballast failures may be accompanied by discolouration or distortion of the ballast enclosure, odors, or smoke. The lamps are internally protected and are meant to fail safely at the end of their lives. Industry associations are working toward advising consumers of the different failure modes of CFLs compared to incandescent lamps, and to develop lamps with inoffensive failure modes. New North American technical standards aim to eliminate smoke or excess heat at the end of lamp life.

Incandescent replacement wattage inflation


An August 2009 newspaper report described that some manufacturers claim the CFL replaces a higher wattage incandescent lamp than justified by the light produced by the CFL. Equivalent wattage claims can be replaced by comparison of the lumens produced by the lamp.

Dimming



Only some CF lamps are labeled for dimming
Dimmer
Dimmers are devices used to vary the brightness of a light. By decreasing or increasing the RMS voltage and, hence, the mean power to the lamp, it is possible to vary the intensity of the light output...

 control. Using regular CFLs with a dimmer is ineffective at dimming, can shorten bulb life and will void the warranty of certain manufacturers. Dimmable CFLs are available. There is a need for the dimmer switch used in conjunction with a dimmable CFL to be matched to its power consumption range; many dimmers installed for use with incandescent bulbs do not yield acceptable results below 40W, whereas CFL applications commonly draw power in the range 7-20W. The marketing and availability of dimmable CFLs has preceded that of suitable dimmers. The dimming range of CFLs is usually between 20% and 90%. However, in many modern CFLs the dimmable range has been improved to be from 2% to 100%, more akin to regular lights. There are two types of dimmable CFL marketed: Regular dimmable CFLs, and "switch-dimmable" CFLs. The latter use a regular light switch, while the on-board electronics has a setting where the number of times the switch is turned on & off in quick succession sets a reduced light output mode. Dimmable CFLs are not a 100% replacement for incandescent fixtures that are dimmed for "mood scenes" such as wall sconce
Sconce (light fixture)
A sconce is a type of light fixture affixed to a wall in such a way that it uses only the wall for support, and the light is usually directed upwards. It does not have a base on the ground...

s in a dining area. Below the 20% limit, the lamp remain at the approximate 20% level, in other cases it may flicker or the starter circuitry may stop and restart. Above the 80% dim limit, the bulb will generally glow at 100% brightness. However, these issues have been addressed with the latest units and some CFLs may perform more like regular incandescent lamps. Dimmable CFLs have a higher purchase cost than standard CFLs due to the additional circuitry required for dimming. A further limitation is that multiple dimmable CFLs on the same dimmer switch may not appear to be at the same brightness level. Cold-cathode CFLs can be dimmed to low levels, making them popular replacements for incandescent bulbs on dimmer circuits.

Perceived coldness of low intensity CFL


When a CFL is dimmed, its colour temperature (warmth) stays the same. This is counter to most other light sources (such as the sun or incandescents) where colour gets redder as the light source gets dimmer. Emotional response testing suggests that people find dim, bluish light sources to be cold or even sinister. This may explain the persistent lack of popularity for CFLs in bedrooms and other settings where a subdued light source is preferred.

Heat


Some CFLs are labelled not to be run base up, since heat will shorten the ballast's life. Such CFLs are unsuitable for use in pendant
Pendant
A pendant is a loose-hanging piece of jewellery, generally attached by a small loop to a necklace, when the ensemble may be known as a "pendant necklace". A pendant earring is an earring with a piece hanging down. In modern French "pendant" is the gerund form of “hanging”...

 lamps and especially unsuitable for recessed light
Recessed light
A recessed light or downlight is a light fixture that is installed into a hollow opening in a ceiling...

 fixtures. CFLs for use in such fixtures are available. Current recommendations for fully enclosed, unventilated light fixtures (such as those recessed into insulated ceilings), are either to use "reflector CFLs" (R-CFL), cold-cathode CFLs or to replace such fixtures with those designed for CFLs. A CFL will thrive in areas that have good airflow, such as in a table lamp.

Power quality


The introduction of CFLs may affect power quality
Power quality
Power quality is the set of limits of electrical properties that allows electrical systems to function in their intended manner without significant loss of performance or life. The term is used to describe electric power that drives an electrical load and the load's ability to function properly...

 appreciably, particularly in large-scale installations. The input stage of a CFL is a rectifier, which presents a non-linear load to the power supply and introduces harmonic distortion on the current drawn from the supply. In such cases, CFLs with low (below 30 percent) total harmonic distortion
Harmonics (electrical power)
Harmonics are electric voltages and currents that appear on the electric power system as a result of certain kinds of electric loads. Harmonic frequencies in the power grid are a frequent cause of power quality problems.-Causes:...

 (THD) and power factor
Power factor
The power factor of an AC electric power system is defined as the ratio of the real power flowing to the load over the apparent power in the circuit, and is a dimensionless number between 0 and 1 . Real power is the capacity of the circuit for performing work in a particular time...

s greater than 0.9 should be used.

Infrared signals


Electronic devices operated by infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 remote control
Remote control
A remote control is a component of an electronics device, most commonly a television set, used for operating the television device wirelessly from a short line-of-sight distance.The remote control is usually contracted to remote...

 can interpret the infrared light emitted by CFLs as a signal, this limits the use of CFLs near televisions, radios, remote controls, or mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...

s.

Iridescence


Fluorescent lamps can cause window film
Window film
There are many types of window tint available in the market for a wide variety of uses from solar heat reduction to UV protection, privacy to safety and security, decorative applications to heat retention.- Primary properties :...

 to exhibit iridescence
Iridescence
Iridescence is generally known as the property of certain surfaces which appear to change color as the angle of view or the angle of illumination changes...

. This phenomenon usually occurs at night. The amount of iridescence may vary from almost imperceptible, to very visible and most frequently occurs when the film is constructed using one or more layers of sputtered metal. It can however occur in non-reflective films as well. When iridescence does occur in window film, the only way to stop it is to prevent the fluorescent light from illuminating the film.

Use with timers, motion sensors, light sensors, and other electronic controls


Some electronic (but not mechanical) timers can interfere with the electronic ballast in CFLs and can shorten their lifespan. Some timers rely on a connection to neutral through the bulb and so pass a tiny current through the bulb, charging the capacitors in the electronic ballast. They may not work with a CFL connected, unless an incandescent bulb is also connected. They may also cause the CFL to flash when off. This can also be true for illuminated wall switches and motion sensors. Also, most CFLs will not work with light sensor devices, as in a "dusk to dawn" device. Cold-cathode CFLs avoid many of these problems. Timer manufacturers may make products compatible with CFLs.

Fire hazard


When the base of the bulb is not made to be flame-retardant, as required in the voluntary standard for CFLs, then the electrical components in the bulb can overheat which poses a fire hazard.

Outdoor use


CFLs are generally not designed for outdoor use and some will not start in cold weather. CFLs are available with cold-weather ballasts, which may be rated to as low as −23 °C (−10 °F). Light output drops at low temperatures. Cold-cathode CFLs will start and perform in a wide range of temperatures due to their different design.

Differences among manufacturers


There are large differences among quality of light, cost, and turn-on time among different manufacturers, even for lamps that appear identical and have the same colour temperature.

Lifetime brightness


Fluorescent lamps get dimmer over their lifetime, so what starts out as an adequate luminosity may become inadequate. In one test by the U.S. Department of Energy of "Energy Star" products in 2003–04, one quarter of tested CFLs no longer met their rated output after 40% of their rated service life.

Ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 (UV) emissions



Fluorescent bulbs can damage painting
Painting
Painting is the practice of applying paint, pigment, color or other medium to a surface . The application of the medium is commonly applied to the base with a brush but other objects can be used. In art, the term painting describes both the act and the result of the action. However, painting is...

s and textile
Textile preservation
Textile preservation refers to the processes by which textiles are cared for and maintained to be preserved from future damage. The field falls under the category of art conservation as well as library preservation, depending on the type of collection...

s which have light-sensitive dye
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....

s and pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

s. Strong colours will tend to fade on exposure to UV light. Ultraviolet light can also cause polymer degradation
Polymer degradation
Polymer degradation is a change in the properties—tensile strength, colour, shape, etc.—of a polymer or polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalis and some salts...

 with a loss in mechanical strength and yellowing of colourless products.

Efforts to encourage adoption


Due to the potential to reduce electric consumption and pollution, various organizations have encouraged the adoption of CFLs and other efficient lighting. Efforts range from publicity to encourage awareness, to direct handouts of CFLs to the public. Some electric utilities and local governments have subsidized CFLs or provided them free to customers as a means of reducing electric demand (and so delaying additional investments in generation).

More controversially, some governments are considering stronger measures to entirely displace incandescents. These measures include taxation, or bans on production of incandescent light bulbs that do not meet energy efficiency requirements.

In 2008, the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 approved regulations progressively phasing out incandescent bulbs starting in 2009 and finishing at the end of 2012. By switching to energy saving bulbs, EU citizens will save almost 40 TW·h (almost the electricity consumption of 11 million European households), leading to a reduction of about 15 million metric tons of CO2 emissions per year.

Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 have also announced plans for nationwide efficiency standards that would constitute an effective ban on most current incandescent bulbs.

Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

 and Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

 have launched massive incandescent light bulbs replacement programs in order to save energy. In the case of Venezuela, the government was able to save 2000 MW of electricity in the first six months of the 2006 program called Mission Energy Revolution, which by 2007 replaced 20 million incandescent light bulbs with CFL from a total of an estimated 55 million light bulbs in the country. Cuba replaced all the 11 million light bulbs used on the island. Also, Venezuela signed an agreement with Vietnam, one of the largest producers of CFLs in the world, to establish a factory to supply the future demand and hand-outs of government light bulbs.

The United States Department of Energy reports that sales of CFLs have dropped between 2007 and 2008, and estimated only 11% of suitable domestic light sockets use CFLs.

In the United States, the Program for the Evaluation and Analysis of Residential Lighting (PEARL) was created to be a watchdog program. PEARL has evaluated the performance and ENERGY STAR compliance of more than 150 models of CFL bulbs.

Labeling programs


In the United States and Canada, the Energy Star
Energy Star
Energy Star is an international standard for energy efficient consumer products originated in the United States of America. It was first created as a United States government program during the early 1990s, but Australia, Canada, Japan, New Zealand, Taiwan and the European Union have also adopted...

 program labels compact fluorescent lamps that meet a set of standards for starting time, life expectancy, color, and consistency of performance. The intent of the program is to reduce consumer concerns due to variable quality of products. Those CFLs with a recent Energy Star certification start in less than one second and do not flicker. There is ongoing work in improving the "quality" (color rendering index) of the light.

In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 a similar program is run by the Energy Saving Trust
Energy Saving Trust
Energy Saving Trust is a non-profit organisation jointly funded by the British Government and the private sector in order to help fight climate change by promoting the sustainable use of energy, energy conservation and to cut carbon dioxide emissions in the United Kingdom.-Background:The Energy...

to identify lighting products that meet energy conservation and performance guidelines.

External links