# Compact fluorescent lightbulbs
**URL:** https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051
**Category:** Factual Questions
**Created:** [April 29, 2007, 4:25pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051 "2007-04-29T16:25:12Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Scuba\_Ben](https://boards.straightdope.com/u/Scuba_Ben)
#### Post date: [April 29, 2007, 4:25pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/1 "2007-04-29T16:25:12Z")
I have some questions on CFLs, which have been hawked lately as “better lighting at lower electric usage.”
A CFL typically claims a power usage of 17 Watts (IIRC) will provide illumination equivalent to an incandescent bulb of 60 W. How accurate is such a claim? And if a lighing socket is rated for a 60 W (incandescent) bulb, is it safe to use a 60 W CFL, or should I use only a CFL that provides light equivalent to a 60 W incandescent bulb?
Also, CFLs are usually labelled “do not use this bulb in a dimmer circuit.” What safety issue does a CFL present on a dimmer switch? The last time I checked electric circuitry concepts, a dimmer switch is a variable resistor to change the voltage drop across the switch, thereby changing the voltage drop across the bulb, which (in a mathematical equivalent of Ohm’s Law) reduces the power and illumination output of the bulb. Ought a CFL work just the same?
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### Author:  [@What\_Exit](https://boards.straightdope.com/u/What_Exit)
#### Post date: [April 29, 2007, 4:47pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/2 "2007-04-29T16:47:23Z")
The 15w bulbs are closer to 75 watt incandescent.
A 15w CFL produces 900lumens and the 75 watt is 930lm.
One of the advantages to CFLs is that if an outlet is rated for only 60 watts, you can use a 23w CFL which would provide 1500lm which is slightly higher than a 100w incandescent (1330lm).
Standard CFLs are not designed to be dimmed, but there are more expensive versions that are. This part might not be quite correct, however the CFL requires a minimum wattage to glow and provide light. An incandescent is a simple glowing resistor. So lower the power and lower the light output. CFLs use solid state technology to energize the Fluorescent gas. The are a very different circuit.
Jim
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### Author:  [@BJMoose](https://boards.straightdope.com/u/BJMoose)
#### Post date: [April 29, 2007, 5:03pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/3 "2007-04-29T17:03:24Z")
The wattage rating on fixtures is more a consideration of how much _heat_ they can tolerate.
I don’t think I’ve ever seen a 60-watt CFL. If you can find one, go for it
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### Author:  [@Gentle\_Robot](https://boards.straightdope.com/u/Gentle_Robot)
#### Post date: [April 29, 2007, 5:03pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/4 "2007-04-29T17:03:30Z")
CFLs blow out in a dimmer circuit. It’s not dangerous, it just doesn’t work.
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### Author:  [@GingerOfTheNorth](https://boards.straightdope.com/u/GingerOfTheNorth)
#### Post date: [April 29, 2007, 6:58pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/5 "2007-04-29T18:58:56Z")
I’d buy stock in them in Canada. The federal government plans to outlaw regular bulbs as of 2012.
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### Author:  [@AskNott](https://boards.straightdope.com/u/AskNott)
#### Post date: [April 29, 2007, 7:47pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/6 "2007-04-29T19:47:20Z")
I’m grumpy about the concept of outlawing incandescents. I have four fixtures that use decorative bulbs with a candelabra base (like a night light socket.) I have seen no CFLs with that base, and CFLs would look strange in a chandelier. One bathroom fixture uses 6 globe bulbs, each a little bigger than a baseball. The beauty of the fixture would be gone if I had a row of little helixes.
I have one outdoor light on a photoelectric dusk-to-dawn switch. I suppose I could just wire past the switch and run it 24/7, and it would be cheaper than running the old bulb at night.
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### Author:  [@kanicbird](https://boards.straightdope.com/u/kanicbird)
#### Post date: [April 29, 2007, 8:17pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/7 "2007-04-29T20:17:09Z")
[QUOTE=AskNott]
I have four fixtures that use decorative bulbs with a candelabra base (like a night light socket.) I have seen no CFLs with that base, and CFLs would look strange in a chandelier. One bathroom fixture uses 6 globe bulbs, each a little bigger than a baseball. The beauty of the fixture would be gone if I had a row of little helixes.
[/QUOTE]
Then you have not been looking. They have both available and they look and work fine. The twisty stuff is hidden in the outer shell glass housing.
> [@](#):
>
> I have one outdoor light on a photoelectric dusk-to-dawn switch. I suppose I could just wire past the switch and run it 24/7, and it would be cheaper than running the old bulb at night.
This is what I did, running a CF 13 W bulb 24/7 uses less power then a 60W at night - but now I put in solar lights for that and now keep the CF bulb off.
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### Author:  [@panamajack](https://boards.straightdope.com/u/panamajack)
#### Post date: [April 29, 2007, 8:18pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/8 "2007-04-29T20:18:16Z")
[QUOTE=Scuba\_Ben]
The last time I checked electric circuitry concepts, a dimmer switch is a variable resistor to change the voltage drop across the switch, thereby changing the voltage drop across the bulb, which (in a mathematical equivalent of Ohm’s Law) reduces the power and illumination output of the bulb.
[/QUOTE]
Not all dimmer switches work that way. Some, probably most new ones, use a chopper circuit that provides pulses of varying width, as it’s more efficient. An incandescent bulb just filters the pulses to produce a dim glow, but this won’t work for a fluorescent bulb. It doesn’t much matter to this question, as either dimmer designed for an incandescent won’t work on a fluorescent.
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### Author:  [@InternetLegend](https://boards.straightdope.com/u/InternetLegend)
#### Post date: [April 30, 2007, 4:25am UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/9 "2007-04-30T04:25:39Z")
If you haven’t looked at CFs lately, you probably don’t have any idea of the variety that’s now available. The twisty, somewhat large models are still out there, but there are also candelabra-base bulbs, smaller bulbs, bulbs that look almost the same as incandescents - if you can’t find a large selection at your local hardware store, try looking online.
I used to think I’d never be happy with CFs instead of incandescents because of the color temperature of the bulbs. I perceived their light as being bluish and very harsh. After doing a more comprehensive search earlier this year, I discovered that you can get CFs with a color temperature that’s comparable to that of incandescents (2700 - 2800 K), and after replacing most of the bulbs in our house with these, I find I’m perfectly happy with them.
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### Author:  [@emmaliminal](https://boards.straightdope.com/u/emmaliminal)
#### Post date: [April 30, 2007, 4:41am UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/10 "2007-04-30T04:41:11Z")
If you go by label-stated lumens, rather than “equivalent watts,” in my experience the claims are accurate: the CFLs give equal light at far lower electric usage, which is why we’ve put them in every lamp and overhead fixture in the house. They also have dramatically better heat performance, which is why we put one in the fridge when its standard appliance bulb burned out a few months ago.
And yes, you can get them in any size or base configuration you like, these days. I’ve bought 'em at big-box stores like Home Depot, chain drugstores like Walgreens, supermarket groceries, and online. You can definitely get candelabra-style bulbs if you want them. They are, of course, more expensive than incandescents but if you figure their total-lifecycle cost yada yada they’re significantly cheaper.
And definitely yes, they are no longer butt-ugly in terms of light color.
Plus, and this is key for me, they neither flicker nor buzz like the crappy old tube ones.
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### Author:  [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)
#### Post date: [April 30, 2007, 4:43am UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/11 "2007-04-30T04:43:38Z")
As stated, the wattage restriction commonly placed on lighting fixtures refers to incandescent rating. You _could_ install CFLs of that rating, but things would be really bright. 😉 That was the solution for folks who wanted more lighting than a recessed can fixture (Hi-Hat) was rated for. List your detailed questions, and we’ll talk next Saturday.
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### Author:  [@kanicbird](https://boards.straightdope.com/u/kanicbird)
#### Post date: [April 30, 2007, 10:45am UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/12 "2007-04-30T10:45:36Z")
[QUOTE=emilyforce]
hey also have dramatically better heat performance, which is why we put one in the fridge when its standard appliance bulb burned out a few months ago.
[/QUOTE]
This may not be all that helpful as CF bulbs lifespan is partly dependent on starting surges. A fridge bulb has frequent startup without the long run time.
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### Author:  [@Scuba\_Ben](https://boards.straightdope.com/u/Scuba_Ben)
#### Post date: [April 30, 2007, 12:54pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/13 "2007-04-30T12:54:01Z")
[QUOTE=danceswithcats]
As stated, the wattage restriction commonly placed on lighting fixtures refers to incandescent rating. You _could_ install CFLs of that rating, but things would be really bright. 😉 That was the solution for folks who wanted more lighting than a recessed can fixture (Hi-Hat) was rated for. List your detailed questions, and we’ll talk next Saturday.
[/QUOTE]
YAFI, YGI.
- CFL electrical safety issues, as noted in my OP.
- Are CFLs available that provide full-visible-spectrum light?
- What is the total cost of ownership, including haz-mat disposal? Are CFLs worth the extra initial cost?
- How is availability at Home Despot and similar big-pallet stores?
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### Author:  [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)
#### Post date: [April 30, 2007, 1:19pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/14 "2007-04-30T13:19:14Z")
[QUOTE=kanicbird]
This may not be all that helpful as CF bulbs lifespan is partly dependent on starting surges. A fridge bulb has frequent startup without the long run time.
[/QUOTE]
I took it that the point was that the fridge didn’t have to dispose of the heat generated by the light, not that the light itself saved significant power.
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### Author:  [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)
#### Post date: [April 30, 2007, 1:48pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/15 "2007-04-30T13:48:19Z")
[QUOTE=GingerOfTheNorth]
I’d buy stock in them in Canada. The federal government plans to outlaw regular bulbs as of 2012.
[/QUOTE]
Yeah, I’ve heard about that. I hate when government does that. The economics should drive everyone to use them, but there are certainly applications where people might prefer incandescents.
What will the government do in 2011 when LED lamps surpass CFLs in cost and efficiency? Outlaw CFLs?
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### Author:  [@Keeve](https://boards.straightdope.com/u/Keeve)
#### Post date: [April 30, 2007, 2:18pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/16 "2007-04-30T14:18:20Z")
[QUOTE=CookingWithGas]
The economics should drive everyone to use them, but there are certainly applications where people might prefer incandescents.
[/QUOTE]
Not only are there \*applications \* where people would prefer incandescents, but there are also \*economics \* where people would prefer incandescents. Namely, if I am low on funds and need a few bulbs, I’d get the incandescents (because they are cheaper in the short term) rather than the CFLs (which are cheaper only in the long term).
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### Author:  [@Lunar\_Saltlick](https://boards.straightdope.com/u/Lunar_Saltlick)
#### Post date: [April 30, 2007, 2:22pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/17 "2007-04-30T14:22:15Z")
To answer the first question in the OP, I find the claims dubious at best. The CFLs that I’ve bought (15w) claimed to be approximately equivalent to 60-watt incandescent. Well, maybe there’s a case to be made for those claims, but experience in my basement shop leaves me scratching my head and squinting. At 17w, I’d say you’re getting closer. I have a feeling it entirely depends what you’re doing and how far you are from the light source. But I can safely say that seeing a fine registration mark on a piece of red oak with an incandescent 60w bulb six feet away is easier than seeing the same registration mark on the same wood with a 15w CFL. There’s a notable difference. I’m going to get some 17w and maybe 20 and see how they work.
Don’t get me wrong. I’m using CFLs, but I’m not thrilled with the claims that are being made.
Should I just forget watts entirely and look at claims for lumens, as **emilyforce** suggests? Does most CFL packaging state the lumens? If I want slightly better than the lumens delivered by the average incandescent 60w, I’m looking for what… 1000 lumens? Are the claims for lumens accurate?
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### Author:  [@DrDeth](https://boards.straightdope.com/u/DrDeth)
#### Post date: [April 30, 2007, 7:48pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/18 "2007-04-30T19:48:15Z")
There are also LED bulbs, which use even less electricity and last for so long their “life” is more or less not an issue. Cost is crazy, but if you need a not so bright bulb in a place where it will burn 24/7 and it is hard to get to; then LED’s are a solution.
I have found “full spectrum” CFLs for 99cents each at the bargain store. So price isn’t really such a issue.
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [April 30, 2007, 10:10pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/19 "2007-04-30T22:10:31Z")
[QUOTE=DrDeth]
There are also LED bulbs, which use even less electricity.
[/QUOTE]
It depends, really.
If you want broad-beam white light, fluorescent bulbs are the most efficient, followed by white LEDs, followed by incandescent. If you want monochromatic light and/or narrow-beam white light, LEDs are the most efficient, followed by fluorescent bulbs, followed by incandescent.
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### Author:  [@panamajack](https://boards.straightdope.com/u/panamajack)
#### Post date: [April 30, 2007, 11:22pm UTC](https://boards.straightdope.com/t/compact-fluorescent-lightbulbs/402051/20 "2007-04-30T23:22:20Z")
While we’re at it, LEDs are dimmable by the same methods, though they won’t necessarily produce exactly the same brightness curve as an incandescent on the same dimmer (but it would at least work, and probably well enough).
**Lunar Saltick** , going by lumens is definitely better than just watts, especially when comparing different lighting methods. The lumen is a measure of the radiant power in roughly the visible range (as opposed to the output you can’t see, like the infrared from an incandescent). A more detailed explanation can be found [here](http://hyperphysics.phy-astr.gsu.edu/hbase/vision/lumpow.html#c1). I don’t know specifically how claimed accuracy is checked, but it’s probably the responsibility of the company.
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