Editing Fluorescent lamp (section)

===Luminous efficacy===
Fluorescent lamps convert more of the input power to visible light than incandescent lamps. A typical 100 watt tungsten filament incandescent lamp may convert only 5% of its power input to visible white light (400–700&nbsp;nm wavelength), whereas typical fluorescent lamps convert about 22% of the power input to visible white light.{{r|GE1978|p=20}}

The efficacy of fluorescent tubes ranges from about 16 lumens per watt for a 4 watt tube with an ordinary ballast to over 100 [[Lumen (unit)|lumens]] per watt<ref name="spiraltubes">{{cite web|author=Panasonic|title=Panasonic Spiral Fluorescent ceiling lights, 124.3lm/W|url=http://panasonic.co.jp/corp/news/official.data/data.dir/jn100609-1/jn100609-1.html|access-date=2010-09-27|archive-date=2011-02-11 |archive-url=https://web.archive.org/web/20110211100002/http://panasonic.co.jp/corp/news/official.data/data.dir/jn100609-1/jn100609-1.html|url-status=live}}</ref> with a modern electronic ballast, commonly averaging 50 to 67&nbsp;lm/W overall.<ref>{{cite web|url=http://members.misty.com/don/|title=Light and Lighting Facts and Bits of Data!|author=Klipstein, Donald L.|access-date=2007-12-29|url-status=dead|archive-url= https://web.archive.org/web/20071228015052/http://members.misty.com/don/|archive-date=2007-12-28 }}</ref> Ballast loss can be about 25% of the lamp power with magnetic ballasts, and around 10% with electronic ballasts.

Fluorescent lamp efficacy is dependent on lamp temperature at the coldest part of the lamp. In T8 lamps this is in the center of the tube. In [[T5 fluorescent lamp|T5 lamps]] this is at the end of the tube with the text stamped on it. The ideal temperature for a T8 lamp is {{convert|25|C|F}} while the T5 lamp is ideally at {{convert|35|C|F}}.