book_cover_big.gifSome time ago I wrote about the advantages of compact fluorescence lamps (CFL) and a life cycle analysis (LCA) of these devices described in the literature[1]. Basic outcome was that CFL’s indeed do give overall resource savings[2]. In an LCA you have of course to assume an average lifetime of the CFL, typically taken as 5 times[3] that of a regular incandescent lamp (ICL). Because CFL’s are  so much more complex to make than ICL’s,  the resource savings benefit would fall apart if the CFL does deviate substantially from the assumed lifetime.

The  positive LCA outcome convinced me to replace many of the ICL’s in my house by CFL’s and accept the high upfront cost (which is easily 5 times as expensive as ICL’s). I bought about 15 lamps. Much to my surprise and frustration within a year I had 3 failures. Note that I bought the CFL’s from a top brand but  that the manufacturer gives no guarantee whatsoever in case of an early failure.

Therefore, I did a quick and dirty web search to see what one can find about reliability of CFL’s. Well not too much. Two interesting leads I found though.

The first one is a study from the Energy Federation Inc., published in 2002[4]. Over the period 1994-2001 four big brand and four little brand manufacturers were tracked for sales and returns. The big brands had a return rate of 1.4%[5]. Much more detail is in this report such as relation between return rate and wattage of the lamp so I recommend you go to their website and read the report [6].

Based on this you can expect on average one early failure out of 70 CFL’s that you will buy[7]. Clearly, my failure rate (3 out of 15) is much higher. And what is most frustrating is that there is no warranty on these lamps. If they fail after 6 months or so what can you prove? Nothing.

But I am not the only on suffering from this problem. See the blog ( The author is actually logging the number of failures (there are many!!) he is experiencing and has a good tip: note down on the lamp the date that you put the CFL in operation and……. hold on to the original receipt. You may have a chance to get your money back from the manufacturer although don’t have to high expectations on this. If you have similar experiences or recommendations to share please put in a comment.

© Copyright 2010 John Schmitz


[2] Parsons, David. “The Environmental Impact of Compact Fluorescent Lamps and Incandescent Lamps for Australian Conditions”, The Environmental Engineer 7(2): 8-14 (2006).

[3] Actually numbers vary, you can find numbers as high as 10!

[4] Bradley Steele, The Performance and Acceptance of Compact Fluorescent Lighting Products in the Residential Market; Energy Federation, Inc

[5] Little brands were running slightly higher at 1.5%


[7] This should be a worse case return rate as you may expect that the CFL manufacturers would have improved the reliability of their products since 2002

book_cover_big.gifA few blogs ago,  I wrote about the life cycle analysis (LCA) of Compact Fluorescence Lamps (CFL’s,)[1]. CFL’s do “consume” during their life indeed about 5 times less electricity than incandescent light bulbs (and CFL’s live about 4 times longer). However, the manufacturing of CFL’s is much more complicated and therefore environmentally more demanding than classical bulbs and rightfully the question was raised that when you sum it all up would the environmental advantage still hold? After a careful and detailed LCA, a team of Australian researchers came with the answer: a big yes!

However,  it was pointed out by the researchers at the University of Ghent[2], Belgium, that one needs to look not just at the environmental impact (for  factors such as global warming, ozone depletion, toxics emission, acidification, etc.) of a certain product but also need to take into account  resources such as organic and inorganic, fuel and feedstock, renewable and non-renewable, energy and materials. It is here where thermodynamics kicks in using the concept of entropy[3] (as already suggested by Nicholas Georgescu-Roegen[4] quite a while ago). Entropy, can be used to describe the degradation of resources during the manufacturing and actually usage of products. One can say, very roughly, that the faster and further away from equilibrium a certain production process is done, the more energy is degraded and made not-available anymore to do further work. This is described by an increase in entropy and is non-reversible, i.o.w. high quality energy (such as energy contained in fossil fuels for that matter) is turned into low quality energy (heat).

This sort of analysis is then used to study the environmental impact of bio-foods versus large scale agriculture produced foods. And sure enough you can find situations where bio-foods (because of their poor yields or their transport over large distances) have more negative impact on the environment than have traditional produced foods. It was found[5] that if bio-beans are locally produced they are environmentally better than conventional produced beans. But when the beans needed to get transported from other areas to make it to our stores the balance can easily change and even reverse the situation! Bio-potatoes are always worse than conventional potatoes because they have such a lower yield per surface area land[6].

Therefore, before drawing conclusions on the impact of a given process or product on the environment or resources a careful evaluation (LCA) needs to be done. Such an evaluation is not a trivial matter at all and can only be done by qualified people.


© Copyright 2009, John Schmitz




[3] As a matter of fact a concept of « exergy » is used but it has a very close relationship to entropy



[6] See also: and

book_cover_big.gifLately the compact fluorescent lamp (CFL) is strongly recommended to replace the incandescent light bulbs (ILB). The main reason is because CFL’s can save a considerable amount of energy during their lifetime; at least that is what is claimed.

Before scrutenizing that claim closer, first a few facts about the lamps it self. The classical ILB, that has been with us basically since the invention of generating light out of electricity operates through a simple principle. A (tungsten) wire is heated through the passage of current to a temperature of about  3000 °C. At that temperature the wire (acting as a black body) emits almost white light. In contrast, the CFL is much more complicated and operates on the principle of a gas discharge. When a gas at lower pressure is subjected to the passage of a current a complex chain of events takes place that eventually results in the generation of UV radiation. When UV light hits a proper chosen phosphorous layer (coated on the inside of the glass tube) the UV light gets converted in visible light. The phosphorous layers are now so sophisticated that the color of the light of a CFL matches that of an ILB. CFL’s can live 4 times longer than ILB’s.

But there is more to tell. A CFL of  18W generates as much light as an ILB of 100W. Thus the amount of electricity needed to drive the lamp is a factor of 5 lower for the CFL and that is at first sight of course a big advantage. Certainly if you realize that about 25% of the electricity generated in the world is used for lighting purposes! However, if you hold an ILB in one hand and a CFL in the other hand you feel immediately a big difference in weight. This is because a CFL is much more complicated to operate than an ILB. A CFL needs an electronic circuit (called a ballast) to ignite and maintain the gas discharge in the tube. This ballast contains a substantial number of components. Thus the question arises if you take into account all the energy for manufacturing, shipping and dispose a CFL, will the energy balance then still be in favor of this lamp versus that of the ILB?

The answer to such a question can only be obtained by a careful Life Cycle Analysis (LCA). Several LCA’s have been done for CFL’s and ILB’s. A recent one is done by David Parsons[1] from the university of Southern Queensland, Australia. In the rest of this blog I quote a few of his conclusions. In an LCA many energy and environmental aspects of a given product are analyzed:

  • Components, processes, materials and quantities used
  • Manufacturing
  • Packaging
  • Transportation
  • Energy used in retailing and wholesale
  • Energy usage during usage
  • Energy losses in transmission lines
  • Impact assessment on environment
  • Disposal

Parsons does then a careful analysis of the two lamps for the items listed above. His conclusion is straightforward: “CFL’s are a significant better source of light from an environmental point of view than ILB’s maily because of their much more efficient use of energy”. He also touches on the problem that CFL’s contain a bit of mercury (about 3 mg)[2] that may pose a problem during disposal. However, he compares that with the amount of mercury that is emitted to the atmosphere by coal fired power plants. Again he comes to the conclusion that also on this aspect CFL’s outperform IBL’s with a factor of 5 in terms of environmental impact: “This analysis serves to confirm that the claimed environmental benefits of CFL’s over IBL’s is largely true and further that it is true on almost any measure…”

That is good news for the planet I think.

2008 © Copyright John Schmitz

[1] Parsons, David. “The Environmental Impact of Compact Fluorescent Lamps and Incandescent Lamps for Australian Conditions”, The Environmental Engineer 7(2): 8-14 (2006).

A link to this article:

[2] The mercury is needed to facilitate ignition of the gas.