Talk:Compact fluorescent lamp

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Contents 1 CFL energy consumption compared to incandescent bulbs 2 How Much Carbon Does One CFL Keep Out Of The Atmosphere? 3 Mercury pollution claims 4 LED lamp 5 Vote to remove "neutrality" banner 6 Payback period neutrality

[edit] CFL energy consumption compared to incandescent bulbs

Forgive me for pointing this out if it's been covered above somewhere (I only skimmed most of this talk page), but the article's discussion over energy consumption seems to use two different sets of figures. From the article:

CFLs use about a quarter of the power of incandescent bulbs. For example, a 15-watt CFL produces the same amount of light as a 60-watt incandescent bulb (approximately 900 lumens or 60 lumens per watt). A comparison of the purchase and operating costs of these two light sources follows. The kilowatt-hour (kWh) is the unit used to sell electrical energy in most countries. The cost of electricity in the United States ranges from $0.06 to $0.38 per kWh, with an average cost in May 2006 of $0.106 per kWh [1] (also see Electricity rates.) For convenience, a rate of $0.10 per kWh is often used for estimating the running costs of appliances.

The CFL, therefore, will save $36.00 in electricity (compared to the incandescent bulb) during its rated life. Some American discount stores sell packages of CFLs for about $2.75 per CFL and incandescent bulbs for about $0.50 each, a $2.25 difference. The estimated payback period for buying the CFL instead of the incandescent bulb is, therefore, 500 hours, which is 100 days at 5 hours per evening.

The text says 60W vs 15W; the equation uses 75W vs 20W. Likewise, the text says the average cost of electricity is $0.10/kWh, but the equation uses $0.08. I don't know enough about all of this to say which explanation is better, but it's clearly inconsistent. Esrever 17:48, 19 January 2007 (UTC)

The table giving light output of Incandescent lamps is way off. Even standard 1000hr 240V frosted lamps used in the UK do better than the figures listed there. The 120V 750hr and 1000hr frosted lamps used in the US are going to be significantly better than even UK 1000hr 240V lamps. (120V filament lamps are more efficient than 240V filament lamps in this power range, and 750hr lamps are more efficient than 1000hr lamps.) To be meaningful, the table needs to consider 120V filament lamps separately from 220/240V filament lamps in any case because of the significant difference in their efficiencies.
Andrew Gabriel, 81.187.162.107 17:00, 25 March 2007 (UTC)

Having made the above comment, I set about thinking how to correct that table, and decided it wasn't possible, given the descrete lumen figures down the left hand side. What's really needed is a graph, so I knocked one up giving lumens verses Watts for the different lamp ranges. I ignored the incandescent figures in the table as they're wrong, and used Philips figures for standard UK frosted 1000hr GLS (A-line) lamps. I used the table's figures for the CFL's, as I haven't bothered to get better ones, but the kink in the line puts them under question too. For US A-line lamps, I used figures for 1000hr 120V lamps available in the UK, but that only encompasses 60W and 100W, and these might not match common US values. So if someone can dig out all the US 120V values, I'll add them too. I'm not sure if US commonly uses 1000hr or 750hr lamps—be clear and consistent in which data you provide as they;ll be significantly different.

Graph here removed and superceeded by graph below, 28 March 2007

Sorry, the graph source isn't pretty. This is my first time using the tool, and I couldn't work out how to do a number of things I wanted to (in particular, calculations in the coordinate positionings to get the scale and offsets applied without resorting to magic numbers everywhere).
Andrew Gabriel, 81.187.162.107 20:39, 25 March 2007 (UTC)

From the Philips US web site:

• 60W Med 120V A19 FR 1000 Hr 850 Lm
• 75W Med 120V A19 FR 750 Hr 1100 Lm
• 100W Med 120V A19 FR 750 Hr 1600 Lm

The above are 'standard' frosted lamps. Note Philips do not offer 1000 Hr 75W and 100W lamps. I haven't checked Osram/Sylvania/GE. WLD^talk|edits 21:32, 25 March 2007 (UTC)

I note that the discussion is about energy costs and total costs-two different things. When discussing the cost of use, the fact that the incandescent needs to be replaced 7 or so times should enter into the calculations. This appears to have been neglected and may make the high initial cost of CFLs less relevant.Joshua2000 21:15, 25 March 2007 (UTC)

OK, here's the graph with US 750h and 1000h lamps added, data taken from GE's website.
What do people think about replacing the table with this (or something based on it at least)?

I'm in favour. WLD^talk|edits 21:56, 28 March 2007 (UTC)

Interestingly, this clearly shows the 4:1 power ratio of 240V incandescent verses CFL, which is what I've been telling people to use for years, and ignore equivalent power specified on the packaging. It looks like a 3:1 ratio is applicable for 120V lamps.
Andrew Gabriel, 81.187.162.107 19:19, 28 March 2007 (UTC)

I decided that I should not rely on the original table for the CFL light output, given all the other data in that table was wrong. I have replaced it in the graph above with data from Philips web page relating to their PL-Electronic CFL's. This data does look more credible—there is no kink in the line for starters which is a good sign. Also, the light output was slightly higher than the original figures—that could be because the original figures were dated.
Andrew Gabriel, 81.187.162.107 07:47, 31 March 2007 (UTC)

I'd suggest swapping the axes, as currently it's graphing watts against lumens, whereas I think it makes more sense to graph lumens against watts. WLD^talk|edits 08:40, 4 April 2007 (UTC)

Confession: I'm the one who keeps truncating this section, including the above formula-with-pictures. Here's why: the only actual information you're conveying is that, for a given lumen-output, the CFL uses x% of the energy. Anything beyond that, and you're turning this article into cheerleading. There's nothing wrong with providing the positive information about CFLs, but please, avoid "dumbing it down" to embellish simple facts. Wikipedia should provide facts, not make the case for you. And if you're going to include financial comparisons, I see nothing wrong with saying that it "pays back" its initial cost much faster than the prevailing rate of return, but it needs to make clear that this is because you're using a light source a lot of people don't like. For example, how would Wikipedia explain the financial advantages of eating only gruel? Use the same kind of comparison. MrVoluntarist 15:01, 4 April 2007 (UTC)

In general the table is original research as a synthesis of data. It produces values intermediate between those provided by a manufacturer. If it showed only data points rather than the smooth curves it would be acceptable. A table would be the best presentation to avoid original research. The watts definitely should be along the x axis as that is the independent vartiable and the light it produces is the dependent variable. It should be possible to produce a similar chart with the data points and without the continuous curves. I buy a bulb and install it; that is the action I have direct control of. I do not force a bulb to produce a given amount of light and then see what wattage it consumes (alhough in the first 2 years of production of bamboo filament light bulbs in the early 1880, they did in fact adjust the voltage to get exactly 16 candlepower and then note the voltage rating for the bulb). How would 16 candlepower translate to the lumen ratings used today? Edison 15:04, 4 April 2007 (UTC)

I originally started playing with the axis the other way around, but it doesn't physically fit into the wiki article so well. I'll take another look at doing this though. The existing table data is simply completely wrong, as many people have commented. There's no indication where it came from. The lines in the graph enable you to see that a 12W CFL would be equivalent to a 50W filament lamp. Even if you can't buy a 50W filament lamp in your country, that's still useful information. The range of common wattages available in different countries varies in any case. Rough conversion is 12 lumens is 1 candlepower, but they are not measurements of exactly the same thing. Candlepower is defined in terms of a green wavelength in the peak of the eye's response, and lumens are defined as a weighted curve matching all the eye's response. Candlepower is an obsolete concept and is a misleading measurement for non-black-body emitters (such as fluorescent phosphors).
Andrew Gabriel, 81.187.162.107 22:37, 4 April 2007 (UTC)

[edit] How Much Carbon Does One CFL Keep Out Of The Atmosphere?

I've seen many different opinions of this around. Energy Star says on their page that one CFL saves about 450 LBS of CO2 over its lifetime. Other Sites seem to indidcate that one CFL saves that much per year? What is the correct answer? I think it'd be good to have this on the page. Also, how is that figure calculated?

It depends on the power source. Light bulbs themselves don't put any CO2 into the atmosphere.

If the power source is something that produces CO2 (such as a coal-fired power plant), then a compact fluorescent will cause one quarter as much CO2 emission as an incandescent bulb of the same brightness, because it uses a quarter of the electricity. On the other hand, if the power source is one that doesn't generate CO2 (hydroelectric or nuclear, for example), then neither bulb will cause any CO2 to be emitted. Pat Berry 00:09, 31 March 2007 (UTC)

[edit] Mercury pollution claims

While technically correct, I'd like to point out at a few issues with the mercury pollution claim in the article. The main problem I see there is that it only covers mercury pollution from coal power generation, which has reached only around 50% of all energy generation in the US in 2005[2]. Other sources of energy generation do not generate mercury emissions. Even though this is mentioned in the text, the chart may be misleading to those who don't realize that on average mercury pollution from incandescent bulbs should reach 5 milligrams, and from CFL bulbs 5.2 milligrams.

Second, I ran some numbers myself. According to the EPA, about 48 tons of mercury were generated by energy generating companies in 1999[3]. For the same year, DOE shows 3.7 billion MWh of electricity generated[4]. That means that a megawathour of electricity generated on average 13 milligrams of mercury emissions. Given the maximum life of an incandescent bulb of 2000 hours[5], a 75W bulb will burn through 150kWh of electricity during its lifetime, thus being responsible for 1.97 milligrams of mercury emissions. in 8000 hours, assuming the maximum lifetime of a CFL bulb (this number is being disputed on this talk page, but for a moment let's assume it's correct), four 75W incandescent bulbs will generate 7.86 milligrams of mercury emissions, while a single comparable CFL bulb at 20W (again, a disputed fact) will generate 2.1 milligrams of mercury emissions. Add to it the 4 milligrams in the bulb, and you get to 6.1 milligrams. This is, using the best case scenario with the highest CFL bulb efficiency and longest CFL bulb lifespan. Note that shorter lifespans of incandescent bulbs would have no effect on the total mercury emissions level, as their number is derived from the total energy consumed. Jpurdes 23:04, 28 February 2007 (UTC)

Have to be pretty careful about generating numbers yourself ~ No OR Alci12 18:02, 5 April 2007 (UTC)

But what happens to the numbers when you factor in the mercury contained within the CFL itself? Although I can't speak for the US, here in Europe the lamps currently go to landfill, which means that the mercury escapes to the environment. This quantity is certainly more than a few milligrammes per lamp (and certainly a lot more than the article claims). 20.133.0.14 12:25, 1 March 2007 (UTC)

The quantity of mercury in a compact fluorescent has been steadily dropping as technology advances allow less to be used. 2mg seems to be a common figure now, down from around 5mg a few years ago. Contrast this with the average of 3g of mercury in a person's body (originally in the form of mercury amalgam fillings, which is released when cremated), and we can see that you need 1500 compact fluorescents to make up the same level of mercury as the average person's body contributes to polution at death. The contribution from compact fluorescents really isn't such a big deal in the scale of things.

81.187.74.206 08:28, 1 April 2007 (UTC)

The problem is the sheer number of fluorescent lights - many units of 2mg add up to a severe problem. Some crematoria are already removing Mercury from flue gas - see http://www.ospar.org/documents/dbase/publications/p00179_Mercury%20emissions%20from%20crematoria.pdf, and a simple method would be to remove teeth containing amalgam before cremation - the rest of the body burden of mercury is quite small - see http://www.findarticles.com/p/articles/mi_m0907/is_1_59/ai_n15721976/pg_1. WLD^talk|edits 18:45, 1 April 2007 (UTC)

[edit] LED lamp

the market might switch to LED lamps, however the article needs some updating, most market data is from 2001, anyone ? Cheers Mion 13:08, 7 March 2007 (UTC)

i've added a para on the end of #Energy_consumption, based on a New Scientist article David Woodward 05:21, 3 April 2007 (UTC)

[edit] Vote to remove "neutrality" banner

• Remove The banner was placed by a unregistered editor. Any vandal or curmudgeon can put up an ugly banner, and then all visiting readers are subjected to it for weeks or months - and it can't be removed? Why not just fix the problem? As far NPOV is concerned, the article is quite informative and accurate: a slight bias towards CFLs is natural since most of the contributors are probably CFL fans. People write about what they care about.--Anthony717 07:41, 14 March 2007 (UTC)

AFAICT, someone did try to present the disadvantages in the article. But they were immediately edited back out again, and the sensationalist slant put back. 81.157.133.142 17:19, 16 March 2007 (UTC)

• I vote to keep the banner. The bias is not "slight". See the Total Environmental Impact section above. --72.244.191.252 14:54, 15 March 2007 (UTC)
• Remove.Mion 15:09, 15 March 2007 (UTC)
  • Reason, better is a small banner in the section instead of disputing the whole article. Mion 15:16, 15 March 2007 (UTC)

• Keep. Environmental issues are too important to make informed decision based on half the arguement. Too many decisions are made in just this manner. The article does not present a truly balance view. As noted here many of the disadvantages of the CFL were bulk edited out. I B Wright 09:39, 16 March 2007 (UTC)

• Keep. Agreed. This is too important an issue. When people are talking about banning all but this product in parts of the world, then it is important that we can agree on the need to ensure neutrality in the debate. One might argue that the article is neutral as it is, but surely no-one could argue that no-one is concerned about its neutrality. Gantlord 14:14, 16 March 2007 (UTC)

• Comment The neutrality tag say that someone doesn't think the article is neutral. That claim has to be described in the talk page and has to have some basis that meets WP:ATT, not a personal feeling nor can it be based on original research. I would like to see a concise statement of what points of view are not adequately covered with some source for that point of view. --agr 14:21, 16 March 2007 (UTC)

• Keep. The talk page seems to have more than enough material to support the dispute banner. 81.157.133.142 17:19, 16 March 2007 (UTC)

Comment A huge amount of the recent discussion on this talk page turned out to be unsupportable allegations by one editor, though. -- Atlant 13:31, 3 April 2007 (UTC)

• Remove. I agree with Anthony717, if there is still a small amount of puffery, it is only in 1 or 2 sections. If people feel that strongly about it we could always move the contentious sections to the talk page and then remove the banner. In my mind there is no doubt that CFLs are an important item for a wikipedia article, the article is suitably neutral for the vast majority of sections. Environmental impact, e.g. mercury has been addressed (BTW the EU has ruled on mercury content in CFLs) and can always be expanded on.David Woodward 10:35, 3 April 2007 (UTC)

• Keep. There is still bias in the article and over-reporting of possible attempts by silly politicians to ban the use of incandescents, giving the wrong impression of what is really happening in the world. Wiki should resist putting these refs into a serious article. They are quite misleading, and yet more publicity for Greenpeace and other extremists.Peterlewis 12:38, 3 April 2007 (UTC)

• Remove. The article overall does not seem to be at issue; individual sections or statements should be flagged where they are questioned. The article neutrality flag should be used primarily when the entire article is biased or only presents one point of view.--Gregalton 13:08, 3 April 2007 (UTC)

• Remove -- Atlant 13:29, 3 April 2007 (UTC)

• Remove Overall, the article seems fairly well balanced. Problems with specific sections should be brought up individually. --dinomite 02:16, 4 April 2007 (UTC)

[edit] Payback period neutrality

The opening paragraph starts with this, that I've flagged: "Increases in the price of electricity decrease the payback time, and incandescent bulbs have been decreasing in price so the payback time for CFLs is now lower.[citation needed]" This seems to me to be a claim that cannot be made without knowing a few of the parameters, including the increase in the price of electricity. A statement that can't be sourced and depends too much on electricity costs (which vary from place to place) should not be in the opening para.--Gregalton 07:09, 7 April 2007 (UTC)

The comment about the lowered price of incandescent bulbs is independent of the price of electricity, but is relevant to the calculation of pay-back time for CFLs. My local Tesco store sells new compact incandescent bulbs for 30-40 pence each, very much lower than the several pounds charged for CFLs. The reduction happened recently and clearly changes the payback argument. By the way, the cost of electricity is also lower now in the UK, so there is even less incentive for using CFLs. I have been busy replacing burnt-out CFLs with incandescent bulbs, with good savings, and better lighting with a softer tone. Peterlewis 07:43, 7 April 2007 (UTC)

So it is specific to one location. Lower-priced incandescent bulbs unambiguously lower the payback period compared to higher-priced incandescent bulbs, but the text currently does not contain that essential qualifier.--Gregalton 08:26, 7 April 2007 (UTC)