Editing Compact fluorescent lamp (section)

===Energy efficiency===
[[File:Electricity use by lightbulb type.svg|thumb|Energy use for different types of light bulbs operating at different light outputs. Points lower on the graph correspond to lower energy use.]]
{{Further|Luminous efficacy}}
Because the eye's sensitivity changes with the wavelength, the output of lamps is commonly measured in [[Lumen (unit)|lumens]], a measure of the power of light as perceived by the human eye. The [[luminous efficacy]] of lamps is the number of lumens emitted for each watt of electric power used. The [[luminous efficacy]] of a typical CFL is 50–70 lumens per watt (lm/W) and that of a typical incandescent lamp is {{nowrap|10–17 lm/W}}.<ref name=doelighting /> Compared to a theoretical 100%-efficient lamp ({{nowrap|680 lm/W}}), CFL lamps have lighting efficiency ranges of 7–10%,<ref>50/680 = 7%; 70/680 = 10%</ref> versus 1.5–2.5%<ref>10/680 = 1.5%; 17/680 = 2.5%</ref> for incandescents.<ref name="Keefe2007">{{cite web|last=Keefe |first=T. J. |title=The Nature of Light |url=http://www.ccri.edu/physics/keefe/light.htm |publisher=Community College of Rhode Island |access-date=18 September 2010 |date=2007 |url-status=dead |archive-url=https://web.archive.org/web/20100612002847/http://www.ccri.edu/physics/keefe/light.htm |archive-date=June 12, 2010}}</ref>

Because of their higher efficacy, CFLs use between one-seventh and one-third of the power of equivalent incandescent lamps.<ref name=doelighting>{{cite web |author=<!-- Unstated --> |title=Lighting |work=Energy Efficiency & Renewable Energy |publisher=[[United States Department of Energy]] |url=http://www.eere.energy.gov/basics/buildings/lighting.html |access-date=2 October 2011 |url-status=dead |archive-url=https://web.archive.org/web/20111015092547/http://www.eere.energy.gov/basics/buildings/lighting.html |archive-date=October 15, 2011}}</ref> Of 2010 world total lighting sales, 50 to 70 percent were incandescent.<ref>{{cite press release |author=<!-- Unstated --> |date=1 Dec 2010 |title=Multibillion dollar benefits of global switch to energy-efficient lighting |url=http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=651&ArticleID=6847&l=en&t=long |publisher=[[United Nations Environment Programme]] |access-date=2 October 2011 |archive-date=14 August 2016 |archive-url=https://web.archive.org/web/20160814025919/http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=651&ArticleID=6847&l=en&t=long |url-status=dead }}</ref> Replacing all inefficient lighting with CFLs would save {{convert|409|TWh|EJ|abbr=off|lk=on}} per year, 2.5% of world electricity use. In the US, it is estimated that replacing all incandescents would save 80 TWh yearly.<ref>{{cite web |title=United States of America |url=http://www.enlighten-initiative.org/portal/CountrySupport/CountryLightingAssessments/tabid/79083/Default.aspx |website=En.lighten |publisher=United Nations Environment Programme |access-date=2 October 2011 |author=<!-- Unstated. --> |date=2010 |url-status=dead |archive-url=https://web.archive.org/web/20120402032922/http://www.enlighten-initiative.org/portal/CountrySupport/CountryLightingAssessments/tabid/79083/Default.aspx |archive-date=April 2, 2012}}</ref> Since CFLs use much less energy than incandescent lamps (ILs), a phase-out of ILs would result in less [[carbon dioxide]] ({{CO2}}) being emitted into the atmosphere. Exchanging ILs for efficient CFLs on a global scale would achieve annual {{CO2}} reductions of 230 Mt (million tons), more than the combined yearly {{CO2}} emissions of the Netherlands and Portugal.<ref>{{Cite web|url=http://www.enlighten-initiative.org/portal/CountrySupport/CLAs/ClimateChangeMitigationBenefits/tabid/79155/Default.aspx|archive-url=https://web.archive.org/web/20130802043445/http://www.enlighten-initiative.org/portal/CountrySupport/CLAs/ClimateChangeMitigationBenefits/tabid/79155/Default.aspx|url-status=dead|title=Climate Change Mitigation Benefits|archive-date=August 2, 2013|website=www.enlighten-initiative.org}}</ref>

{| class="wikitable" style="text-align:center;"
|+ Electric power equivalents for differing lamps<ref name="estar">{{cite web |url=http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_lumens |title=Learn About Light Output: Energy Star |publisher=Energystar.gov |access-date=2012-07-15}}</ref>
|-
! rowspan=2 | Minimum [[Luminous flux|light<br />output]] (lumens)
! colspan=3 | Electric power use (watts)
|-
! [[Incandescent light bulb|Incandescent]]
! Compact fluorescent
! [[Light-emitting diode|LED]]
|-
| 450
| 40
| 9–11
| 6–8
|-
| 800
| 60
| 13–15
| 9–12
|-
| 1100
| 75
| 18–20
| 13–16

|-
| 1600
| 100
| 23–28
| 15–22
|-
| 2400
| 150
| 30–52
| 24–28
|-
| 3100
| 200
| 49–75
| 30
|-
| 4000
| 300
| 75–100
| 38
|}
{{anchor|Heating and cooling}}
If a building's indoor incandescent lamps are replaced by CFLs, the heat emitted 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 when compared to the use of incandescent lamps, resulting in savings in electricity in addition to the energy efficiency savings of the lamps. However, in cooler climates in which buildings require heating, the [[central heating|heating system]] must replace the reduced heat from lighting fixtures. In [[Winnipeg]], Canada, it was estimated that CFLs would only generate 17% savings in energy compared to incandescent bulbs, as opposed to the 75% savings that could have been expected without space heating considerations.<ref>{{cite news |url=http://www.cbc.ca/news/canada/manitoba/efficient-lighting-equals-higher-heat-bills-study-1.856047 |publisher=[[CBC News]] |title=Efficient lighting equals higher heat bills: study |date=2009-03-04}}</ref>