Editing Compact fluorescent lamp (section)

===Lifespan===
CFLs typically have a rated [[service life]] of 6000–15,000 hours, whereas standard [[Incandescent light bulb#Voltage, light output, and lifetime|incandescent lamps have a service life]] of 750 or 1000 hours.<ref>General Electric ''Incandescent lamps TP110'', technical pamphlet published in 1976, no ISBN or Library of Congress number, page 8</ref><ref>{{cite web |title=Osram Dulux EL Energy-Saving Lamps |publisher=Osram |access-date=2007-12-24 |url=http://www.osram.com/pdf/products/general/duluxsortiment.pdf |archive-date=2006-07-22|archive-url=https://web.archive.org/web/20060722104807/http://www.osram.com/pdf/products/general/duluxsortiment.pdf}}</ref><ref>{{cite web |title=IEC 60969: Self-ballasted lamps for general lighting services: Performance requirements |publisher=Collaborative Labelling and Appliance Standards Program |access-date=2007-12-24 |url=http://www.clasponline.org/teststandard.php?no=82|archive-url=https://web.archive.org/web/20080226083943/http://www.clasponline.org/teststandard.php?no=82|archive-date=February 26, 2008}}</ref> However, the actual lifetime of any lamp depends on many factors, including operating voltage, manufacturing defects, exposure to [[voltage spike]]s, [[Shock (mechanics)|mechanical shock]], frequency of cycling on and off, lamp orientation, and ambient [[operating temperature]], among other factors.<ref>{{cite web|last=Damir|first=B|title=Longevity of light bulbs and how to make them last longer|url=http://www.robaid.com/gadgets/longevity-of-light-bulbs-and-how-to-make-them-last-longer.htm|publisher=RobAid|access-date=4 January 2013|date=2012|url-status=dead|archive-url=https://web.archive.org/web/20150819081553/http://www.robaid.com/gadgets/longevity-of-light-bulbs-and-how-to-make-them-last-longer.htm|archive-date=19 August 2015}}</ref>

The life of a CFL is significantly shorter if it is turned on and off frequently or is used in a totally enclosed fixture. This happens because the electrodes in a CFL undergo sputtering every time it is turned on; this also happens in fluorescent tubes. Material from the electrodes is ejected every time sputtering occurs and it is deposited on the fluorescent tube's walls, showing as lamp end darkening. In the case of a 5-minute on/off cycle the lifespan of some CFLs may be reduced to that of incandescent light bulbs. The US [[Energy Star]] program suggests that fluorescent lamps be left on when leaving a room for less than 15 minutes to mitigate this problem.<ref name="energysavers-turn-off">{{cite web |title=When to turn off your lights |url=https://energy.gov/energysaver/when-turn-your-lights |work=Energy Saver |publisher=[[United States Department of Energy]] |access-date=2017-07-22}}</ref> CFLs emit less light later in their lives than when they are new. The light output decay is [[exponential decay|exponential]], with the fastest losses being soon after the lamp is first used. By the end of their lives, CFLs can be expected to emit 70–80% of their original light output.<ref>{{cite conference |last1=Guan |first1=Fumin |last2=Reynolds |first2=Dale |date=May 2005 |title=Topic and Discussions on the Performance Standard and Inspection Methods of CFL |url=http://www.rightlight6.org/english/proceedings/Session_8/Performance_Standard_and_Inspection_Methods_of_CFL/f013guan.doc |archive-url=https://web.archive.org/web/20070923124410/http://www.rightlight6.org/english/proceedings/Session_8/Performance_Standard_and_Inspection_Methods_of_CFL/f013guan.doc |archive-date=September 23, 2007 |conference=Right Light 6: 6th International Conference on Energy-Efficient Lighting |conference-url=https://web.archive.org/web/20070708071826/http://www.rightlight6.org/english}}</ref> The response of the human eye to light is [[Logarithmic scale|logarithmic]]. That is, while the human eye is highly sensitive to changes in the intensity of faint light sources, it is less sensitive to changes in the intensity of brighter light sources since the pupils compensate by dilating or constricting.<ref>{{cite news |last=Halsted |first=Charles P. |date=March 1993 |url=http://www.crompton.com/wa3dsp/light/lumin.html |title=Brightness, Luminance, and Confusion |access-date=2007-10-07 |work=Information Display |publisher=Naval Air Warfare Center Warminster, PA |quote=If the luminance of a viewed light source is increased 10 times, viewers do not judge that the brightness has increased 10 times. The relationship is, in fact, logarithmic: the sensitivity of the eye decreases rapidly as the luminance of the source increases. It is this characteristic that allows the human eye to operate over such an extremely wide range of light levels. |url-status=dead |archive-url=https://web.archive.org/web/20070922063502/http://www.crompton.com/wa3dsp/light/lumin.html |archive-date=September 22, 2007}}</ref> So, presuming the illumination provided by the lamp was ample at the beginning of its life, and the light output of a bulb gradually decreases by 25%, viewers will perceive a much smaller change in light intensity.<ref>{{cite thesis |type=PhD |last=Matković |first=Krešimir |date=December 1997 |url=http://www.cg.tuwien.ac.at/research/theses/matkovic/node15.html |title=Colour Science Basics: Human Vision |access-date=2007-10-07 |work=Tone Mapping Techniques and Color Image Difference in Global Illumination |publisher=Institut für Computergraphik eingereicht an der Technische Universität Wien ([[TU Wien]]) |quote=It is interesting, that despite that incoming light can have a dynamic range of nearly 14 log units, the neural units can transfer the signal having the dynamic range of only about 1.5 log units. It is obvious that there is some adaptation mechanism involved in our vision. It means that we adapt to some luminance value, and then we can perceive data in a certain dynamic range near the adaptation level. One of the most important characteristics that changes with different adaptation levels is the just noticeable difference. |archive-date=2021-06-09 |archive-url=https://web.archive.org/web/20210609115652/https://www.cg.tuwien.ac.at/research/theses/matkovic/node15.html |url-status=dead }}</ref>

Fluorescent lamps get dimmer over their lifetime,<ref>{{cite web|url=http://www.rightlight6.org/english/proceedings/Session_8/Performance_Standard_and_Inspection_Methods_of_CFL/s08-2p013guan.pdf |title=Topic and Discussions on the Performance Standard and Inspection Methods of CFL |access-date=2007-04-13 |url-status=dead |archive-url=https://web.archive.org/web/20070927202538/http://www.rightlight6.org/english/proceedings/Session_8/Performance_Standard_and_Inspection_Methods_of_CFL/s08-2p013guan.pdf |archive-date=September 27, 2007}}</ref> 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.<ref>{{cite journal |last1=O'Rourke |first1=Conan |last2=Zhou |first2=Yutao |year=2006 |url=http://www.osti.gov/bridge/servlets/purl/881039-K5YRuT/881039.PDF |title=Energy Star Lighting Verification Program (Program for the Evaluation and Analysis of Residential Lighting) Semi-annual report For the period of October 2003 to April 2004 |access-date=2007-04-13 |doi=10.2172/881039}}</ref><ref>{{cite web|url=http://mail.mtprog.com/CD_Layout/Day_2_22.06.06/1400-1545/ID133_Banwell_final.pdf |title=Quality Assurance in Energy Star Residential Lighting Programmes |access-date=2007-04-13 |url-status=dead |archive-url=https://web.archive.org/web/20061209005450/http://mail.mtprog.com/CD_Layout/Day_2_22.06.06/1400-1545/ID133_Banwell_final.pdf |archive-date=December 9, 2006}}</ref>