# Does three 20W fluorescent light bulbs equal one 60W bulb?

**URL:** <https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084>\
**Category:** Factual Questions\
**Created:** [May 23, 2003, 7:08pm UTC](https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084 "2003-05-23T19:08:34Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![InLikeFlynn](https://avatars.discourse-cdn.com/v4/letter/i/f19dbf/32.png) [@InLikeFlynn](https://boards.straightdope.com/u/InLikeFlynn)\
**Post date:** [May 23, 2003, 7:08pm UTC](https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084/1 "2003-05-23T19:08:34Z")

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I know that they would use the same amount of energy to power so they would have to be equal (right?) but, is there any difference in their respective wavelengths?

This problem arose from trying to light up a fish tank with enough intensity to sustain delicate sea anemones!

Would both instances penetrate the water to the same depth?  
😕

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**Author:** ![InLikeFlynn](https://avatars.discourse-cdn.com/v4/letter/i/f19dbf/32.png) [@InLikeFlynn](https://boards.straightdope.com/u/InLikeFlynn)\
**Post date:** [May 23, 2003, 7:16pm UTC](https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084/2 "2003-05-23T19:16:35Z")

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Sorry MOD! I really didn’t mean to double post!!

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**Author:** ![FatBaldGuy](https://avatars.discourse-cdn.com/v4/letter/f/ecd19e/32.png) [@FatBaldGuy](https://boards.straightdope.com/u/FatBaldGuy)\
**Post date:** [May 23, 2003, 7:17pm UTC](https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084/3 "2003-05-23T19:17:25Z")

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In a word, no.

I just replaced a light fixture in my kitchen which used two 60 W incandescent bulbs with a new one using two 18 W fluorescent bulbs. The new one gives off as much, or more, light than the old one, but uses less power.

Since fluorescent bulbs use a completely different technology to create illumination, there are differences not only in the amount of light produced, but also in the color temperature (or wavelength). Flurorescent bulbs give off a whiter light than incandescents, which are more yellow in color.

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**Author:** ![chukhung](https://avatars.discourse-cdn.com/v4/letter/c/e79b87/32.png) [@chukhung](https://boards.straightdope.com/u/chukhung)\
**Post date:** [May 23, 2003, 7:35pm UTC](https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084/4 "2003-05-23T19:35:02Z")

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This page, [http://www.thekrib.com/Lights/](http://www.thekrib.com/Lights/), from The Krib is a good place to start for more information about aquarium lighting.

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**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\
**Post date:** [May 23, 2003, 7:43pm UTC](https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084/5 "2003-05-23T19:43:15Z")

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Fat Bald Guy, you misunderstood the question

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**Author:** ![John\_Kentzel-Griffin](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)\
**Post date:** [May 23, 2003, 8:55pm UTC](https://boards.straightdope.com/t/does-three-20w-fluorescent-light-bulbs-equal-one-60w-bulb/177084/6 "2003-05-23T20:55:58Z")

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Duplicate of [Does three 20W fluorescent light bulbs equal one 60W bulb?](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=185903).

I’ll close this one.

**DrMatrix** - GQ Moderator