Talk:Compact fluorescent lamp

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Contents 1 Picture 2 Base-down operation only? 3 Energy used to manufacture CFLs 4 Other_CFL_technologies 5 Comparing CFLs and incandescent bulbs 6 Efficiency calculation complications 7 Trying again with the Comparing CFL's section 8 Dimmable energy saver bulbs 9 Comparison section 10 Houseplants 11 Pollution citation

[edit] Picture

The current picture is a little bland. Perhaps this one would be better? The only difference is that it doesn't show the bottom where the screw-in part is, but I don't think that's vital.PiccoloNamek 10:19, 26 November 2005 (UTC)

Actually, I think that there should be several photos, showing different styles of cf bulb. There are the straight kind, the spiral kind, and then there are various reflector and globe models. Nick 17:31, 26 November 2005 (UTC)

I think that's quite an attractive picure and if you haven't already made it the "lede" picture, I think you should do so.

Atlant 17:54, 30 November 2005 (UTC)

I also think that perhaps we should "gallerize" all of the different types of photos, instead of having them clutter of the side of the article. It would certainly look much nicer. I've gone ahead and done just that. If someone can find a better solution, please feel free to do so.PiccoloNamek 21:45, 30 November 2005 (UTC)

[edit] Base-down operation only?

Also, someone kindly add why some of these bulbs only work in the base down position. Frustrating discovery that.

It's not generally true; I've operated several different brands of CFLs base-up. On the other hand, temperature control is important, both to regulate the vapor pressure of the mercury in the arc tube and to ensure that any integrated ballast doesn't overheat, so it is entirely possible that certain CFLs in certain fixtures will not operate well. For example, many CFLs warn you against operating them in entirely-enclosed fixtures (as they will overheat).

Atlant 13:23, 16 January 2006 (UTC)

Someone please add why -some- of these will not operate with the base up. I have found bulbs that will only operate in a few fixtures and only base down. Some will operate in one base up location and not another. Is there a difference in the fixture itself that makes these bulbs incompatible? Or, is the the up-ness or down-ness of the base? Both variables applying here? Leave aside temperatrue issues for the moment as I am curious about why they won't even turn on when base up.

If they absolutely won't even "turn on" when base-up, then there's either a sensor within the lamp or a mechanical defect in the lamp. (I assume that the ambient conditions (temperature, humidity, line voltage, etc.) between your base-down and base-up tests are the same? You're not saying, for example, that "when the lamp is placed outside, base-up, in -20C weather, it won't turn on", right?

Atlant 14:56, 16 May 2006 (UTC)

[edit] Energy used to manufacture CFLs

I would like to see information about how mcuh extra energy is used in the manufacturing process of CFLs as compared to Incandescent bulbs. It seems to me that this could be a major factor in weighing up the environmental benefit of switching to CFLs and should be addressed on this page.

Does anyone have this sort of information?

Cheers Matt

I imagine it is not an issue. Both have glass bulbs. Both have screw bases. CFLs have a plastic cover for the ballast: that's low-energy to make. CFLs have a few electronic bits: they are too small to need much energy to make. Anthony717 06:54, 15 April 2006 (UTC)

Even so, this information is important, otherwise the calculations could be meaningless (particularly if the cost of manufacturing is subsidised and so not reflected in the cost of bulb purchase). —The preceding unsigned comment was added by 86.129.160.253 (talk • contribs) .

I, too, would like to see a thorough comparison of the energy input in manufacturing each. Also, don't fluorescent bulbs contain hazardous materials like mercury, and the phosphorescent coating isn't the most pleasant material to have around. And, what is in those ballasts, anyway? Even the disposal of fluorescent bulbs now seems to require a large energy input. 66.157.239.71 00:26, 25 July 2006 (UTC)

Old phosphors were hazardous but any phosphor made since the middle of the last century is pretty-much non-toxic. Old ballasts contained pitch and other tarry substances; high-power-factor ballasts often contained PCBs in their capacitors. Modern electronic ballasts are much more innocuous, containing nothing more hazardous than in any other electronic equipment including your cell phone; you can pretty well discount modern ballasts from your equations.

Mercury remains the most interesting toxic in fluorescent lamps, but as has been pointed out more than once, if we're comparing coal-generated electricity, the amount of mercury in a fluorescent lamp is substantially less than would be released by burning the coal to power incandescent lamps for equivalent light for an equivalent period of time.

Atlant 00:39, 25 July 2006 (UTC)

I agree that this is a non issue, let me explain why.

To begin, a CFL lasts 11 times as long as an Incandescent. So really, we have to compare the energy to manufacture 11 Incancescent light bulbs compared to 1 CFL.

Lets say you bought in bulk, and got 11 Incancescent light bulbs at $0.20 a piece for a grand total of $2.20. And then lets say you bought a CFL for $5.

Ok, so right there is a price difference of $2.80.

Now, lets now assume that the whole reason for that price difference right there, is entirely due to a difference in energy input cost. And If that energy came in the form of electricity, well then it required an extra

28 kW-hours to produce 1 CFL as compared to 11 Incandescent light bulbs.

Ok, but how much does using a CFL save in energy as compared to an incandescent? It saves:

The extra energy required to manufacture the CLF is at least an order of magnitude less than the energy it saves. JabberWok 01:37, 27 July 2006 (UTC)

[edit] Other_CFL_technologies

Moved from Compact_fluorescent_lamp#Other_CFL_technologies

edit: CCFL's are not more efficient. Hot cathodes are more efficient... There is a reason why standard CFL's are hot cathode.

Well, less heat = typical CCFL is low powered - 3 to 5 watts. —The preceding unsigned comment was added by 66.114.93.6 (talk • contribs) 16 May 2006.

It's actually tough sometimes to determine which cathodes are really "cold" and which aren't. For example, "instant start" fluorescent lamps (or ordinary lamps operated as instant-start lamps with just one electrical connection per end) start as CCFLs but the impinging electron/ion beam rapidly heats a spot on the filaments to red-hot incandescence and they then operate as ordinary hot-cathode fluorescents. Even on older, large-scale CCFLs (the ones that look like "neon tubes"), there's often a hot spot that develops on the tubular electrodes.

I've not yet taken apart a modern LCD-backlightish "CCFL" to see what the electrode structure actually looks like, but I'd still be surprised to find they operate as truly cold cathodes; the ends of the lamps certainly get hot, suggesting there's a lot of heat developed by the "electrode losses".

Atlant 15:02, 16 May 2006 (UTC)

I am not 100% sure, but the actual temperature of the cathode doesn't really determine hot/cold cathode. I think the key here is whether or not the cathodes are activly emitting and thus committing electrons to the arc stream or not. The idea is; "hot cathodes" actively contribute electrons to the arc stream, thus reducing voltage requirements from the ballast. So, typically cold cathode fluorescent lamps are very low current (and thus thin tubes) to keep the size and requirements of the ballast down. Given that, and if someone would produce a CCFL with the same light output and current rating as normal CFLs, the CCFL would probably (still) have lower efficiency, mainly because the ballast would be large and costly. So, the prospect of having large ballasts with multi-kilovolts at a few hundred milliamps keep the tube size (and current rating) down to ten milliamps or less. And as with all light bulbs, smaller = lower efficiency. —The preceding unsigned comment was added by 66.114.93.6 (talk • contribs) .

[edit] Comparing CFLs and incandescent bulbs

Can data about the poor power factor of CFLs be added to this article. Power Factor has a major bearing on energy calculations and the resulting energy bills. Using power factor in calculations is the only correct way to compare the efficiency of AC devices.

The efficiency calculation in this article is wrongly using the DC Power formula for an AC device !

In this article, Power = V x I. Probably unknown to you, this is only correct for DC devices, and is wrong for AC devices.

Way back in 1908, a gentleman working at GE by the name of Steinmetz gave the correct formula to measure the power used by an AC load. It is still taught to all EEs today. http://www.invent.org/hall_of_fame/139.html Unbelievable pity that Wikipedia has such mistakes.

The formula for power used by a AC device is Power = V x I x Cos(theta); energy = power x time [kilowatt-hour] Cos(theta)of the V and I is the Power factor of your device. Restating - Cos(theta) is the cosine of the phase angle between the voltage and current flowing into the CFL. It has huge effect on the efficiency of any AC device.

CFLs operate on AC. But CFL ballasts needs DC to operate. So CFLs have bridge rectifiers [typically IN4001 diodes] at the ballast inputs. Bridge rectifiers cause a big phase difference between the voltage and current going into a CFL. This is the cause of the poor power factors in CFLs.

This is also known as supply line pollution. CFLs are major culprits in supply line pollution. As you may have noticed, large phase differences are bad for any AC device. They decrease the efficiency of your device. Hugely.

In a good CFL, the Cos(theta) factor is 0.6.In bad CFLs it is 0.5. This means that the efficiency calculation in this article is wrong. Pl get a EE to explain it to you. Then please correct the calculation. The power factor of a light bulb is 1. It is twice better than a CFL.

Utility companies in many countries are now beginning to take action against users who have reactive loads. a reactive load is any load with non unity power factor. Soon people using CFLs will be charged an extra levy for polluting the power lines. The Indian capital of New Delhi is in an advanced stage of this amendment. I know that the Sydeny Energy counci is also proceeding on similar lines.

And yes, I am an Hons EE graduate working for the 'Big Blue' computer company. I am the one who yesterday wrote the para that was rm'd as 'unreadable rant'. Problem is I design illumination in million square feet offices for a living, and I know what I am talking about, but since my input is going against the un-informed attitude of 'see how wonderful CFLs are!', it is being labeled as 'unreadable rant'. Typical for Wikipedia.

I noticed a uttery hopeless discussion on cold cathodes in this thread. It was the blind leading the blind. So happnes, that I am also the orignal writer of the Cold Cathode article in this Wikipedia. http://en.wikipedia.org/wiki/Cold_cathode. I wrote it in 2003. 216.84.11.250 was my IP address at that time. —The preceding unsigned comment was added by Ashvini1988 (talk • contribs) 07:01, 23 November 2006.

Hi, Ashvini. Please sign your talk-page posts, and please add comments to the bottom of existing discussions. You seem to be muddling several things. Reactive loads cause phase shifts between current and voltage. Diodes used in bridge rectifiers are not reactive components, capacitors and inductors are. On the other hand there is a power-factor issue related to rectifiers, due to their non-linearity. This leads to problems like stray currents flowing in three-phase neutral, but these are problems for the electricity supply company to solve, not the consumer. Very few electricity supply companies will base the design of their sub-station networks on what they read in Wikipedia, I suspect, but maybe we could mention it somewhere, if citable sources can be found.

If there is a power-factor problem associated with CFLs (and we have no cited source that there may be), it will work to mean that the real power consumed is less than the apparent power, not more. Lastly the simple calculation P = I x V applies perfectly well in AC, provided all three are RMS values. Have a read of the Power factor article too. --Nigelj 18:48, 23 November 2006 (UTC)

Niglej: Just run a CFL thru a power factor meter and you will know. If you dont have access to a power factor meter, then find someone who does. Get into a illumination lab. Then you fix the wrong calculation. Stop looking for citations. They dont exist, because the professionals with power factor meters dont bother about Wikipedias, and they dont write citable papers about CFLs. This article is giving the wrong message.

I am haranguing on this because my 9 yr old was on this page, writing something for his class, I looked over, saw your calculation, and I felt truly tormented.

The calculation is just so misleading. You have simplified things so much that they misrepresent reality. I am troubled by the thousands of kids like mine who are reading it, and getting incorrect information.

This article, in its current form, can be justifiable labeled as 'misleading', and 'ignorant'. CFLs are not as good.

And yes, ordinary RMS meters only give correct readings for perfect cosine waves. For non cosine loads like a CFL, readings from RMS meters are completely useless. So watch out for RMS. [btw: this is the key problem with all the 'over unity' folks. They dont know that RMS meters read correct RMS only if the energy is following a cosine law, so they get all these over unity readings]

On reactive loads- any load that causes a phase diff between V and I is reactive. Diodes in AC circuits are reactive. In pf correctin work, we routinely build 'simulated inductors' using op-amps and hi voltage FETs. It not a reactive load according to you, but it is. Althought it has no reactive components. Device non linearity causes harmonics, not phase difference. Pl mind the difference.

Now can you pl fix the wrong calculations ?

Things are only half as good as you are portraying them to be.

CFL pf = 0.5 to 0.6

ashvini1988.

Diodes aren't "reactive". And as the circuitry in CFLs becomes more and more sophisticated and utility companies become more demanding, don't be surprised to find power-factor correction included (although I don't think it is yet). Regardless, power factor probably isn't a factor here; I think you'll find that the stated power consumption of CFLs already is stated in terms of Watts (so real power), not VA or anything that needs further adjustment.

Atlant 13:18, 24 November 2006 (UTC)

I agree, Atlant. I don't think we can do anything with the ideas above that claim to be beyond all documentary evidence and outside of any scientific explanation. --Nigelj 20:45, 24 November 2006 (UTC)

Please try and comprehend that the CFL with '5W' on the box actually draws 10 watts, because its power factor is 0.5 (5/0.5 =10). This is not a matter of 'opinion', engineering never was polls based. You stick a meter in there and learn it. Please try understand that one will pay for 10watt-hour of energy per hour of a '5W' CFL. Not 5watt-hour, as the print on the cover would have you believe. The cover of a CFL doesn't tell you that it draws 5watts @ 0.5 power factor. Its the responsibility of people like us, with wiki's, to draw the attention of the world to this dirty secret.

But I am sure you wont change your wrong methods because you are not educated enough to comprehend the true complexity of the CFL lie.

It is such a shame that the grand experiment of 'wisdom of the masses' has turned out into a 'squabble between people with various vested interests'.

It is now a repeating thread on most wiki articles. People with high school knowledge dominate the discussions, using the crutch of 'lack of citations' and 'not relevant' heads to keep articles in their wrong shape and misleading form.

What is needed is experts, not masses. I saw wiki as a liberator from the yoke of Encyclopedia Britanica. Not so. Wiki has evolved into a great squabbling ground between people with the 'know how' and 'people with too much time'. One must be weary of the Wiki.

Once again- the calculation of the relative comparison of CFL and Incandescent Lamps in this page is wrong. It is off by 200%. This article makes the CFLs look twice as good as they really are. That is because this article is ignoring the fact that the power factor of a CFL is a poor 0.5 [which is only half as good as an incandescent lamp with a pf=1.0]. This means that your actual 'on the books' energy savings will be 200% lesser than what this article makes you believe. You will only save half as much money in your monthly utility bill as this article makes you believe. Beware of the misleading 'efficiency' of a CFL. Take power factor into account. A CFL is not as efficient as it says on its cover. Thanks . ashvini1988.

I added the following paragraph to this section: "However, virtually all of the energy from light bulbs of any type is converted into heat. During cold months when a building is being heated, the heat produced by a light bulb is helping to heat the building, and this needs to be taken into account when calculating the energy cost of different types of bulbs. In a typical home using electric heat, for example, light bulbs of any type do not produce any electricity cost during cold months, since the heat produced by the bulbs simply offsets heat that would have been produced by the home's heating system".

It is inaccurate to look at the cost of different types of bulbs without taking into consideration the above. An inefficient incandescent bulb may turn out to be 100% efficient if the "waste heat" from the bulb is used to heat the building the bulb is in. --Xyzzyplugh 13:15, 24 June 2006 (UTC)

What you are proposing is a theory (is there references for this?), which is why I removed the paragraph for the moment. But at least it's a testable theory. Let me put that paragraph into different words: "Using CFLs instead of Incandescent bulbs results in a utility bill that is no smaller, because any savings in electricity have to be made up for in heating costs." That's what another way of saying it, correct? I'm stating it this way because now it's more obvious how it can be tested.

So now the question is: taking into account both heating and electricity costs, does using CFLs save money overall? I haven't seen any references personally on this, so I can't comment. Anyone else? JabberWok 16:54, 24 June 2006 (UTC)

I highly doubt that a source will be found on the final sentence. Everything I've ever read on the comparison between fluorescent and incandescent bulbs totally ignores the fact that the waste heat generated by bulbs might actually be useful. If you want to remove the final sentence from the paragraph entirely due to it being unsourced, that would be understandable, although I find it to be a simple logical conclusion. The first part of the paragraph is simply self-evident. Light bulbs produce heat, homes need to be heated, therefore the bulbs are helping to heat the home. Sources could easily be found demonstrating these things, but I don't think that would be necessary. --Xyzzyplugh 17:09, 24 June 2006 (UTC)

Actually, it just occurred to me why the paragraph you're proposing is incorrect. And it comes down to one thing:

• Energy from electricity costs more than energy from Natural gas. (And the reason for that is because you have to burn things - like natural gas - to make electricity.)

So because of that, heating your home with a space heater (which is what an incandescent light bulb essentially is) costs more than heating your home with natural gas.

That's why, for any home heated by natural gas, switching over to CFLs results in a overall lower cost.JabberWok 17:12, 24 June 2006 (UTC)

This doesn't contradict anything that I said. If you notice, I specified "In a typical home using electric heat" in the last sentence of my paragraph above. What you're pointing out is true, of course. The usual method which is suggested to compare CFL's and incandescents is a gross simplification. It doesn't take into consideration whether the home needs to be heated, or the method of heat, and it also doesn't take into consideration whether the home is being air conditioned. If you're air conditioning a home, this doubles the inefficiency of incandescent bulbs versus fluorescents since you are paying for the extra electricity used to produce all that waste heat that incandescents produce, then you're paying to remove that waste heat with your air conditioning system. --Xyzzyplugh 17:32, 24 June 2006 (UTC)

Just so I can get a rough order of magnitude...

Lets say, during a winter month, a home uses something like 50 Therms of natural gas. In kW-hours that's:

Ok, so it takes about 1,500 kW-hours to heat a home home for a month.

To compare with energy cost on the main page, using a 60 Watt light bulb for 8000 hours (which would take several years) would create about 480 kw*hours of heat.

So the heat released from one bulb is a small effect, at least.

But now, is the heat from a light bulb useful heat? People turn up or turn down their thermostats depending on air temperature. So does the heat from a lightbulb mostly end up in the air? Or does it end up in a nearby wall or ceiling where it doesn't contribute to a person's general feeling of warmth?JabberWok 18:22, 24 June 2006 (UTC)

Your statement that light bulbs produce almost no heat is an odd one, if you think about it. If bulbs aren't producing a significant amount of heat, then they must not be using a significant amount of energy, and so why not just use incandescent bulbs?

I have electric baseboard heat in my home, all of my heat comes from electric heating units along the walls near the floor (and from light bulbs and any other electric appliances which might be running). As the heat from the baseboards manages to circulate its way through the entire home, including warming hallways and bathrooms which don't have any baseboard heaters at all, clearly electrically produced heat doesn't just sit in one spot. The bathrooms are not noticeably cooler than the rooms which have baseboard heaters in them, either. The baseboard heaters don't have fans or any such thing, they just get hot and the heat makes its way out of them. It may well be that ceiling light fixtures are less efficient as more of the heat may be absorbed into the ceiling. However, many light bulbs will be placed in lamps or chandeliers where they are not directly next to the ceiling.

The simplest demonstration that the heat from a light bulb is not all being absorbed into the ceiling is to just feel the ceiling nearby. An incandescent light bulb gets so hot it burns you if you touch it, while the ceiling a few inches away doesn't feel hot at all. Furthermore, if the heat were all sitting in one spot and not circulating into the room, the ceiling would quickly catch fire.

We don't need to be doing original research to edit this article though, not even simple research like feeling our ceilings. But the fact that heat from a light bulb heats the air in a room is self-evident. The very existence of electric baseboard heating, which contains no fans, ought to be evidence of this. --Xyzzyplugh 04:55, 25 June 2006 (UTC)

It surely heats the room. However the effiency of incandescent bulbs in heating a room (in comparison to an eletric heater which of course depends on the type of eletric heater anyway) is debatable and uncertain. Remember Without any reliable research, we should only mention that it may reduce heating costs since the effect could easily be negligible. (BTW, you might want to remember the 3 ways of heat transfer; conduction, convection, radiation and the relevance. Also remember that hot air travels up. It's easily possible incadescent bulbs as 'heaters' may increase the heat gradient in the room i.e. there will be a great difference between the temperature close to the ceiling and the floor and so you may find they don't actually have a great effect in reducing heating costs). Nil Einne 22:18, 4 August 2006 (UTC)

[edit] Efficiency calculation complications

Xyzzyplugh added and JabberWok reverted-out the following text:

However, virtually all of the energy from light bulbs of any type is converted into heat. During cold months when a building is being heated, the heat produced by a light bulb is helping to heat the building, and this needs to be taken into account when calculating the energy cost of different types of bulbs. In a typical home using electric heat, for example, light bulbs of any type do not produce any electricity cost during cold months, since the heat produced by the bulbs simply offsets heat that would have been produced by the home's heating system.

There's some truth to this but it's still more complicated than that. One, electrically heated houses are pretty rare, and compared to any other fuel source, even an electric heat pump, the heat produced by any lamp is costly pure-electric heat. Two: It's not entirely clear that all of the heat produced by all household lamps is captured as useful heat into the envelope of the house. In particular, certain ceiling-mounted lights lose heat into the ceiling and roof spaces that would ordinarily not be heated.

Still, in northern climates where the need for heating predominates over the need for cooling there's quite a lot of sense to this argument that you need to at least consider the "electric heat" provided by lighting; it's certainly not the 100% loss that a simple calculation might suggest.

Atlant 22:57, 24 June 2006 (UTC)

Note my answer above. Also, one thing which many people seem to be missing is the issue of luminous efficacy is complicant. The difference is about 2-3x it appears depending on type of CCFL and incandescent bulb. Some of this is obviously going to heat however some of it to infrared. While the infrared is obviously going to have some effect on heating in the room I would assume (it's been a while since I did physics), most of it will effect on the objects in the room, the floor, ceiling etc. However this will affect the heating in the room I don't know. Or in conclusion it's clearly really complicated as you say and we really have no idea how much of the heat is usefully captured into the envelope of the house... Nil Einne 22:43, 4 August 2006 (UTC)

[edit] Trying again with the Comparing CFL's section

I'm putting the following in place: "The above calculations are a simplification, as virtually all of the energy from light bulbs of any type is converted into heat. During cold months when a building is being heated, the heat produced by a light bulb is helping to heat the building, and this needs to be taken into account when calculating the energy cost of different types of bulbs. In addition, during hot times of the year when a building is being air conditioned, CFL bulbs produce extra savings over incandescent bulbs because extra energy is being used by the air conditioning system to remove the waste heat which the bulbs are producing".

I removed the previous final sentence with which there was disagreement. Anyone still have problems with this new paragraph? It may not be written as well as it could be. I'd like to see some mention of the fact that the usual calculations given are a simplification, but going into too much detail would probably be tedious and unnecessary.--Xyzzyplugh 19:13, 30 June 2006 (UTC)

[edit] Dimmable energy saver bulbs

Turns out some companies now offer CFLs that can be dimmed: http://www.nolico.com/saveenergy/dimmable_lamps.htm Kar98 17:33, 9 July 2006 (UTC)

[edit] Comparison section

I trimmed down the last paragraph about heat effects to a more manageable 60 or so words.

Although it is too anecdotal to put in the article, I read that Japanese residents (especially in small apartments that don't have central heating) often use incandescent bulbs in the winter and CFLs in the summer.

Radiant heat sources are comparatively wasteful because they lose more heat through floors, walls and ceilings. This is a seriously important problem. Fan-forced induction heaters (including electric central heating systems) are substaintially more efficient than space heaters with exposed coils or exposed incandescent bulbs for increasing indoor air temperature. Anthony717 00:07, 10 July 2006 (UTC)

[edit] Houseplants

Does the spectrum of fluorescents limit their use in grow lights for houseplants or greenhouses (or whatever)? Photosynthesis only works with certain wavelengths, right? — Omegatron 00:33, 18 July 2006 (UTC)

If we're talking small-scale, there shouldn't be any problem. Plants grow well-enough under a wide variety of light colors and certainly grow under good-old "cool white" phosphors.

If we're talking large scale (say greenhouse scale), then you'd avoid CFLs because other light sources are notably more efficient; T8 and T5 fluorescents seem like a good step up from CFLs but metal halide lamps seem to be popular among certain sub-cultures. ;-)

Atlant 12:50, 18 July 2006 (UTC)

That's not why I was asking, but I'll keep it in mind in case I ever decide to take up a new hobby.  :-)

I was leaving a lamp on to compensate for low light levels and a sickly plant, and a friend said it was a waste of power because they don't grow in light from fluorescents. Just curious if they were practical for that. — Omegatron 13:47, 18 July 2006 (UTC)

[edit] Pollution citation

It appears the 3.5 million car figure comes straight from the cited "Make the Switch" campaign. This is at least somewhat in the neighborhood of the one bulb per household being equivilent to one million cars off the road claim made on the Energy Star page. —The preceding unsigned comment was added by 64.8.70.20 (talk • contribs) .

Flickering and buzzing are common problems in older fluorescent light fixtures, but are easily avoided in new fluorescent bulbs. Older bulbs (and some cheap new bulbs) have magnetic ballasts that hum at 120 cycles per second, which some people can perceive as a flicker, and which may be accompanied by a buzz as the lamp cycles. (An easy way to identify them is the 1-2 second delay when you switch the light on.) New electronic (or solid state) ballasts operate at 24,000 cycles or more per second, eliminating the flicker. The buzz is also gone, since there is no magnetic pulsing happening.