 are taking the world by storm. But can they cause headaches due to flickering? Most experts say no: Unlike the older long tube fluorescent lights, the flicker rate of the new CFLs is way too fast for the human eye or brain to detect.)
Energy-efficient compact fluorescent light bulbs (CFLs) are taking the world by storm. But can they cause headaches due to flickering? Most experts say no: Unlike the older long tube fluorescent lights, the flicker rate of the new CFLs is way too fast for the human eye or brain to detect.
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Dear EarthTalk: Can those energy-efficient compact fluorescent light bulbs that are popular now cause headaches because of the flickering they do? I converted my whole house over last fall and both my kids were complaining of headaches on and off.
-- Sandy, Eugene, OR
With a switch to energy efficient compact fluorescent (CFL) light bulbs already in full swing in the U.S. and elsewhere—Australia has banned incandescents, Britain will soon, and the U.S. begins a phase-out of incandescents in 2012—more and more complaints have arisen about the new bulbs causing headaches.
Many experts say that the issue is being overblown, however, that there is no scientific evidence that the bulbs cause headaches and that a kind of hysteria has grown out of a small number of anecdotal reports.
Industry experts acknowledge that day-to-day exposure to older, magnetically ballasted long tube fluorescent bulbs found mostly in industrial and institutional settings could cause headaches due to their noticeable flicker rate. The human brain can detect the 60 cycles per second such older bulbs need to refresh themselves to keep putting out light.
However, modern, electronically ballasted CFLs refresh themselves at between 10,000 and 40,000 cycles per second, rates too fast for the human eye or brain to detect. “As far as I’m aware there is no association between headaches and the use of compact fluorescent lamps,” says Phil Scarbro of Energy Federation Incorporated (EFI), a leading distributor of energy efficiency-related products—including many CFLs.
But Magda Havas, an Environmental & Resource Studies Ph.D. at Canada’s Trent University, says that some CFLs emit radio frequency radiation that can cause fatigue, dizziness, ringing in the ears, eyestrain, even migraines. You can test to see if CFLs in your home give off such radiation, she says, by putting a portable AM radio near one that’s on and listening for extra static the closer you get. She says that such electromagnetic interference should also be of concern to people using cell phones and wireless computers.
Sometimes headaches are due to eyestrain from inadequate lighting. When replacing an incandescent bulb with a CFL, pay attention to the lumens, which indicate the amount of light a bulb gives out (watts measure the energy use of a bulb, not the light generated). A 40-watt incandescent bulb can be replaced by an 11-14 watt CFL because the lumen ouput is approximately the same (490); a 100-watt incandescent can be replaced by a 26-29 watt CFL, both providing about 1,750 lumens. If you’re still skeptical, replace a 40-watt incandescent with a 60-watt equivalent 15-19 watt CFL, which will boost lumens to 900.
Another consideration is color temperature (measured in degrees “Kelvin”). CFLs rated at 2,700 Kelvin give off light in the more pleasing red/yellow end of the color spectrum, closer to that of most incandescents. Bulbs rated at 5,000 Kelvin and above (usually older ones) give off a less pleasing white/blue light.
The Environmental Defense Web site provides a handy chart comparing the watts and lumens of incandescents versus CFLs, along with further discussion about color temperature.
CONTACTS: EFI, www.efi.org; Environmental Defense, www.edf.org/page.cfm?tagid=630.
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36 Comments
Add CommentThere is also the effect where the older bulbs cause actual headache from 60Hz flicker, and the newer bulbs are "guilty by association," just due to the color of light they emit. For all the talk of "warm color" CF bulbs - they still are overwhelmingly green like their cheap industrial ancestors. The CFs don't flicker, but if you've abused your optic circuits with green 60Hz flicker for years, just seeing that color green again can bring the memories.
Reply | Report Abuse | Link to thisAlso, there's the fact that these mercury vapor based lights have been associated with school, work, and other possibly unpleasant places for a couple of generations now. It will take a while to unlearn that as well.
Not to mention, they're full of mercury, & no better for the environment at all. :(
Reply | Report Abuse | Link to this"There is no evidence that the bulbs cause headaches" - spin, spin, spin
Reply | Report Abuse | Link to thisHoweverm the negative cannot be proven - that the bulbs DO NOT CAUSE headaches.
LED's and OLED's - the lighting of the future.
"Full of mercury" is another overblown statement. There is a miniscule amount of mercury vapor in the bulbs, and that's being reduced further by the industry. If the bulbs are recycled w/o breaking, there's a net 0 effect. Even if broken, a CFL would release less mercury than would be caused by coal generation for an incandescent substitute.
Reply | Report Abuse | Link to thisOne CFL in every US home would save the equivalent energy of taking a million cars off the road. That's a BIG environmental benefit! Let's quit flickering, and get on with it . . . and move to the next better solution when it becomes available.
CFL's are an interim solution. The whole "bulb" concept of lighting is going to change. Why have lighting in a single-point source??
Reply | Report Abuse | Link to thisLED's are much more flexible and can me made into small array's.
OLED's, while not market-ready yet will allow "surfaces" to generate soft, even light at very low power consumption.
With the recent discovery of the connection between audio and image processing in the brain, would it still be correct to say the mind cannot detect flickering in the 10k range - well within the range of hearing? Don't get me wrong, I'm all for saving energy, I just would like to see a better understanding of the interactivity between the audio and visual cortex before I concern myself with "possible" headaches.
Reply | Report Abuse | Link to thisGet that clear button away from the submit...This is the second time I have hit the clear instead of the submit and I will not waste my time again this month writing a comment to lose it inadvertently. Too bad, my comment was a good one..
Reply | Report Abuse | Link to thisI think there may be something to this. I had *never* heard that CFL's caused headaches and since we made the switch sometime last year I've been having a lot of headaches, and I normally don't get them. I've been to the Dr. & the optometrist and neither mentioned any physical problems.
Reply | Report Abuse | Link to thisThanks for the article Sciam I'm going to try replacing the CFL's with LED's and see if that makes a difference.
CFL lights DO flicker - in my testing they flickered at 100 Hz (we have 50 Hz electricity here in the southern hemisphere.)
Reply | Report Abuse | Link to thisYou can check it for yourself using a light sensor probe (taking 1000 samples per second) that is connected to a datalogger.
There is a portion of the population that is sensitive to this frequency of flicker and will potentially experience migraines, seizures etc.
To Hotblack,
Reply | Report Abuse | Link to thisGod you talk shit man(or woman) . There is bugger all mercury in the bulbs.
The ignorance of those who keep on with this are like those who scream about cell phones killing us with brain cancer.
Now I have to lay down and try to become calm.
I do not feel that the question was answered in the article. There are some unknowns that went unacknowledged - starting with candide's comment that the negative cannot be proven: the SA writer failed to mention this, and blew off the experiences of people getting head-aches while using these bulbs as inconsequential anecdotal evidence. I feel that anecdotal evidence is a great place to start questioning, and why not? I find CFL bulbs to be very annoying to my eyes, although I cannot say why. It is more important to me that they are annoying/causing a sense of eye strain and fatigue then that an SA writer tells me there is no problem. Why the need to close off the question by the SA writer? Why not leave it open for further exploration?
Reply | Report Abuse | Link to this"Florescent"?? Please proofread the headlines and text if you want me to take your article seriously. Also, to improve your credibility, turn to sources outside the industry in question.
Reply | Report Abuse | Link to thisWhy does the SA writer rapidly close off the question of whether or not CFL bulbs cause problems for at least some people? The SA writer's article will be ignored as those of us experiencing eye strain and annoyance from CFL bulbs switch them out because of our "anecdotal" experiences. I will take my fatigue and eye strain around CFL bulbs more seriously than the SA writer's claims that there is no effect. As candide said, the negative cannot be proven, that the bulbs do not cause head-aches/fatigue... at the same time, I can tell you I feel strain/fatigue when using them. Hmmm... Basically, the article leaves us in a worse place than where we started, because it encourages people to disregard their experiences. How does the writer know the human brain cannot detect the higher refresh rates? Maybe we are detecting it in a way that has not been measured, or thought of?
Reply | Report Abuse | Link to thisSorry for double response...
Reply | Report Abuse | Link to thisI have suffered from headaches due to florescent lights on many, many occasions. Most doctors (and people, generally) deny that the headaches ever occurred or that florescent lights caused them. But the problem was so severe that I kept my kitchen light off and purchased several shaded lamps to use throughout my apartment instead - which brings me to another issue: incandescent lights emit far more pleasing light in a shaded lamp than florescent lights. Now perhaps I was using florescent bulbs (when I briefly tried them in the lamps) with the wrong lumens or specs, but the light was not classy at all - very cheap - not at all comparable to Silvania incandescents.
Reply | Report Abuse | Link to thisLet me tell you something about most experts. Most experts are conventional thinkers. That's why they have to call themselves experts - because if they had to admit that the body of knowledge which they profess to be an expert about ever changed, then they would have to admit that they are no longer an expert - and most experts loathe to do that. After all, being a so-called expert is their claim to fame. So unless something is substantiated with clinical trials, textbooks, and the like, it must not be true. Of course nothing could be further from the truth. Medication side effects beyond what a medication's label describe do occur, and florescent lights can cause headaches - I've had them.
Reply | Report Abuse | Link to thisI love this spin. Taking the world by storm. CFLs are being MANDATED by a bunch of thugs who get their thrills over telling other people how to live their lives.
Reply | Report Abuse | Link to thisThe Incandescent bulb is a superior bulb. Cheap, reliable, easy to manufacture and produces natural lighting. There is no valid reason to give them up (spare me the tired blather about global warming. A warmer climate would be beneficial to mankind). Again, this is nothing more than a bunch of elitist thugs who feel they have the moral duty to dictate you how you live.
This is nothing more than a propaganda piece to push SA's environmentalist agenda. CFLs are stupid. They are expensive, contain mercury (isn't it amazing how mercury is now suddenly harmless), and produce harsh lighting.
Reply | Report Abuse | Link to thisIncandescent bulbs are dirt cheap to make, reliable and produce natural lighting. They are a superior product. Period.
The CFL Advertising Account
Reply | Report Abuse | Link to this[CFL's are great, except for one little thing]
Read the rest at
http://easyopinions.blogspot.com/2008/04/cfl-advertising-account.html
First things first...
Reply | Report Abuse | Link to thisThe "article" is a response not a full blown article. So quit being harsh on the amount of research.
The article states that current accepted theory suggests that modern CFLs under the right conditions are unlikely to cause headache.
But you read Scientific American so it's very likely that you know at one time current accepted theory said asbestos was also safe.
So considering the answer to CFLs causing headaches is "probally not", if your still concerned switch the blubs out without notifying the subjects (the kids). If the headaches go away PUT THE CFLs BACK again without telling the kids. Then observe the results. If it recoccurs REPEAT THE PROCESS. That is really the only way a Scientific American would go about this.
Listening to only what industry says or only modern supersition is a path to nowhere.
My assumption ... the headaches are something seasonal ... a mild allergy to an indoor or outdoor pollen or dust ... a recent increase in video games or televison
If it were my kids I would try the "clean your room experiment" ... "maybe your headaches are caused by a messy room". While the expeirment wil most likely fail at least the rooms would get picked up for a few weeks.
10 days ago I moved into a newly built 5-star green house that has only CFL's in it. I detest the ugly, harsh light that comes from them, even when covered by nice fixtures. I normally do not get headaches, but had one all day Sunday and it turned into a migraine yesterday which I needed to be treated by a doctor for. My eyes still feel strained and I plan on changing every bulb in my new house from CFL's to LED or incandescent until this headache thing gets straightened out.
Reply | Report Abuse | Link to thisI have a brand new compact fluorescent in my desk lamp. I can see/feel it flickering easily. It is driving me mad. I bought a whole box full and I hope they are not all the same. I've had two other brands of cfb burn out after only 2 months of service. There is a lot of garbage on the market apparently.
Reply | Report Abuse | Link to thisTim
Your forms are crap. I wrote a long comment, went through your onerous registration only to have my comment deleted. Not very Scientific huh?
Reply | Report Abuse | Link to thisAnyway, I agreed that some CFBs do flicker visibly. Any info otherwise is bs. They also can burn out rapidly. There is garbage on the market.
The following is a direct response to this comment.
Reply | Report Abuse | Link to this"Full of mercury" is another overblown statement. There is a miniscule amount of mercury vapor in the bulbs, and that's being reduced further by the industry. If the bulbs are recycled w/o breaking, there's a net 0 effect. Even if broken, a CFL would release less mercury than would be caused by coal generation for an incandescent substitute."
Do you have any idea how many CFLs end up in landfills at this point? Now make every home use only CFLs and watch how many millions of CFLs end up in landfills. The Mercury from one fluorescent bulb can pollute 6,000 gallons of water beyond safe levels for drinking.
Clean coal and nuclear power are much better solutions but they've been stigmatized for so long by environMENTALists that they can't even be considered. Much like others are claiming fluorescent lights have been. We have both newer and older system ballast lighting systems where I work. They both put out harsh unnatural light compared to all but the cheapest incandescent bulbs.
It should be up to the individual consumer which bulb is best suited for their application. Not the government or any other group. The one who pays the electric bill should be able to choose their own best lighting source. If CFLs are that GREAT then the majority of consumers will voluntarily install them.
As for the flickering - When the sun starts to flicker at 100hz then I'll agree that a 100hz flicker has no affect on any human because the can't perceive it. Just because you can't perceive something, doesn't mean that it is good for you.
Please look at the CFL Advantages and Disadvantages section at
Reply | Report Abuse | Link to thishttp://peswiki.com/index.php/Directory:Compact_Fluorescent#Compact_Fluorescent_Lighting_Advantages
We removed 30 CLFs from our house and the unexplained and uncurable migraines, arthritic-like conditions and skin rashes went away that all began when we installed those 3 months earlier. Now with the bulbs gone, we can live again free from pain and suffering caused by these bulbs.
Please look at the CFL Advantages and Disadvantages section at
Reply | Report Abuse | Link to thishttp://peswiki.com/index.php/Directory:Compact_Fluorescent
and
http://peswiki.com/index.php/Directory:Compact_Fluorescent_Lighting_%28CFL%29_Downsides
(Ignore the previous post link)
What is often forgotten (not to mention the disposal, dimming, and mercury problems) is that the "lost" or "wasted" energy associated with incandescent bulbs heats our houses thereby reducing our heating bills. Why do the carbon footprint people absolutely never mention this fact?
Reply | Report Abuse | Link to thisElderly, maybe it's not a bulb or two but there are hundreds of millions out there now, probably soon billions!
Reply | Report Abuse | Link to thisCumulative Mercury in landfills and toxic waste site are where it can really hurt us.
I just started a blog on it, please stop by:
http://stoppingatthegreenlight.wordpress.com/
I've never understood why environmentalists are pushing toxic chemicals into every household? Save energy but cause toxic hazards as the tradeoff? I love the fact that when one of these bulbs breaks you are supposed to basically get a hazmat team to clean up the entire exposed area. I can't wait for the legislation banning the use of these bulbs when the toxic nature of them. Also, I am just as sensitive to CFL as to the old fourescents -- they give me bad headaches and I can't get away from them at work, since I work in classrooms full of them. I hate flourescent lights, including CFLs. I like how the person they quote here is someone hawking CFLs to the public. It's like cigarette manufacturers saying they don't know of any health risks to smoking. The CFL industry is being very dishonest. I hope the CFL scam ends soon.
Reply | Report Abuse | Link to thisCFLs are full of toxic substances: I love how the instructions on my CLFs tell me to clear the room and basically go through full hazmat detoxification procedures for an entire exposed room or house, etc. when a bulb breaks. When my kids broke a CFL in the lamp in their room and I looke up more information on them, I immediately replaced all CFLs with traditional lightbulbs. The toxic tradeoff is not worth it. I can't understand why so many so-called environmentalists want to push more toxic chemicals into our homes, workplaces and the environment. Also, I am one of those people that the CFL industry says doesn't exist: yes, CFLs give me horrible headaches, just as traditional, crappy flourescent lights do at work. I hate governments forcing toxic chemicals, eye strain and headaches into our homes. Shame on the so-called environmentalists and the CFL industry for telling so many fibs about their products.
Reply | Report Abuse | Link to thisYes, my CFLs all burned out more quickly than any lightbulbs they replaced! The whole notion of saving on the number of bulbs needed to be purchased (rationalizing higher per unit costs) is, in my experience... rubbish!
Reply | Report Abuse | Link to thisI strongly disagree that CFL's do not cause headaches. Yesterday I visited a large medical center that had installed CFL's in waiting areas since my last visit. I experienced sudden and severe vision and headache problems that I'm sure are attributable to these bulbs. I have experienced previous diagnosed problems with certain fluorescent bulbs. I will find out what specific kind of bulb these were so that I can avoid using them in our home and our children's home, and campaign against their use elsewhere.
Reply | Report Abuse | Link to thisThe perceived flicker is not the actual optical frequency. Even in magnetically ballasted fluorescent tubes, the flicker rate is 100 or 120 Hz (2 half-cycles per AC cycle at mains frequency). It is an effect of the spiked light frequency pattern on the pupil causing a pulsation or flutter response in the pupil.
Reply | Report Abuse | Link to thisMains frequency pulses (the 100/120 Hz pulses) does create a sympathetic pattern of this pupilary flutter, but pulsations at that frequency are not by themselves (directly) perceptible.
The problem with CFs and other fluorescent lighting is in the very spiked light output frequency pattern.
We are seeing this on a practical level, where restaurants and other businesses that depend on comfortable lighting have abandoned fluorescent lighting despite the cost savings.
Regardless, the existence of a known scientific explanation or the lack thereof does not somehow magically make the ill-effects go away. Fluorescent lighting is unpleasant because of very real effects, regardless of whether these effects are fully understood.
- Dog
Well, the study did not have me in it. The new cfl's bother me! your study is based on the assumption that the cycling of newer compacts are at the efficiency stated in this article. If people insist that cfls bother them then I believe we should listen to them, believe them! Someone is making an absolute bundle off the phasing in and deposit structures for the mercury laden "new" cfls.
Reply | Report Abuse | Link to thisIt's amazing to me how many times I am seeing the terms "to the best of my knowledge" and "no evidence." I don't need evidence. I've got the headache! I've had it daily for 4 months now. It comes on late in the day. What do you think that means? I've been in the hospital and had numerous tests done. I've got more tests scheduled. I don't know what they call "evidence" but it seems to me that people getting headaches when they turn on the lights are evidence. There are articles all over the internet written by people who are getting these headaches.
Reply | Report Abuse | Link to thisI love the idea of saving energy but the problem is that they won't attempt to invent a safer light bulb when they don't need to. That is what our government is now causing by banning the current incandescent bulbs. The reasons cited seem to be that the other countries are doing it. I thought we were supposed to be smarter than them. Obviously not!
CFLs only don't flicker when they are new. As they get older, they start flickering terribly (invisibly, yet often subconsciously perceived) and cause problems. If they don't get enough voltage, they flicker as well. In low temperatures they can flicker while they are warming up. Every time they aren't using their maximum brightness,it is a sight that they are flickering. Incandescent light never was capable of flickering with a high enough dept and such crazy spikes and frequencies to cause problems the way CFLs do when not under optimal conditions. People that test them only test new bulbs under the best conditions and say that they are problem-free (if they test them at all), but it are those other conditions that cause people problems. I was very sensitive to such CFLs when they were not used in the best conditions. They have flaws, recognize it! I'm not even talking about RF frequencies or spectrum, or even ultrasound, highly toxic materials they are produced of . It is ridiculous how incandescent light is being banned in country after country.
Reply | Report Abuse | Link to this