# Are CFLs more efficient than conventional fluorescent lights?
**URL:** https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832
**Category:** Factual Questions
**Created:** [June 8, 2016, 2:37pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832 "2016-06-08T14:37:11Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)
#### Post date: [June 8, 2016, 2:37pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832/1 "2016-06-08T14:37:11Z")
Subject line pretty much covers it. If I have a 40-watt fluorescent tube, and a 40-watt CFL (which might be labeled as being equivalent to a 200-watt incandescent bulb), which one puts out more visible light?
---
### Author:  [@scr4](https://boards.straightdope.com/u/scr4)
#### Post date: [June 8, 2016, 2:43pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832/2 "2016-06-08T14:43:39Z")
It’s exactly the same technology. I’d guess a conventional long tube would be slightly more efficient because a CFL is curled up into a spiral, blocking some of its own emitted light.
---
### Author:  [@Alley\_Dweller](https://boards.straightdope.com/u/Alley_Dweller)
#### Post date: [June 8, 2016, 2:47pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832/3 "2016-06-08T14:47:39Z")
[40-watt CFL: 2650 lumens](https://www.1000bulbs.com/product/1602/FC40-FEIS40W50.html)
[40-watt T8 tube: 3750 lumens](https://www.1000bulbs.com/category/f40t8-fluorescent-tubes/)
---
### Author:  [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)
#### Post date: [June 8, 2016, 3:07pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832/4 "2016-06-08T15:07:04Z")
> [@scr4](#):
>
> It’s exactly the same technology.
Is it? AIUI, CFLs use a switched-mode power supply in their base to generate high-frequency AC that gets applied to the tube. Might this have implications for efficiency?
---
### Author:  [@davida03801](https://boards.straightdope.com/u/davida03801)
#### Post date: [June 8, 2016, 3:13pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832/5 "2016-06-08T15:13:45Z")
I think CFL are on the way out and LED soon to be replacing them all over.
I was surprised the other day to find out the LED are now the fixture of choice for lay in ceiling lights at certain places.
---
### Author:  [@scr4](https://boards.straightdope.com/u/scr4)
#### Post date: [June 8, 2016, 3:34pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832/6 "2016-06-08T15:34:03Z")
> [@Machine\_Elf](#):
>
> Is it? AIUI, CFLs use a switched-mode power supply in their base to generate high-frequency AC that gets applied to the tube. Might this have implications for efficiency?
Well OK, I meant the tube itself is the same technology. Ballast technology has improved over time, so a brand new CFL may have a much more efficient ballast (and perhaps better overall efficiency) than a fluorescent tube in an old fixture.
---
### Author:  [@Alley\_Dweller](https://boards.straightdope.com/u/Alley_Dweller)
#### Post date: [June 8, 2016, 3:47pm UTC](https://boards.straightdope.com/t/are-cfls-more-efficient-than-conventional-fluorescent-lights/756832/7 "2016-06-08T15:47:14Z")
> [@davida03801](#):
>
> I think CFL are on the way out and LED soon to be replacing them all over.
>
> I was surprised the other day to find out the LED are now the fixture of choice for lay in ceiling lights at certain places.
It’s not terribly well known, but there are now [LED replacements for fluorescent tubes](https://www.earthled.com/collections/led-t8-tube-replacements-replace-your-fluorescent-t8-t10-t12-lamps-with-led?gclid=COKTmMHhmM0CFcYlgQodi5IPdQ). They come in two varieties: “direct wire” which require you to wire around the ballast and “electronic ballast compatible” which allow you to just replace your old tubes without screwing around with the ballast (electronic ballast required). The prices have come down tremendously in just the last few months.