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Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Submitted by ben on Thu, 02/28/2008 - 01:58.
“Everything is born from dust, and everything ends as dust. The relative importance of what happens in between depends not just on how it lived, but also how long it lived.” - a Ben Kenney original
These numbers account for the life of the bulb though, not the entire life cycle of the bulb. The question of whether we can be more lighting efficient by using compact fluorescent bulbs needs an in depth analysis of how much energy is required to make and recycle the bulb. It’s actually quite complex. Here’s why.
When evaluating energy consumption or CO2 emissions of a technology, the full lifecycle of the product should be considered, not just its lifetime productivity. A proper analysis should include the CO2 emissions or embodied energy associated with all of the raw materials, all of the transportation and distribution, the operation and finally the recycling or decommissioning of the product. You’ll find a couple different names for this type of assessment popping up: energy return on energy invested (EROI), well-to-wheel (these two are typically used for fuels), dust-to-dust, cradle-to-grave or more correctly, life cycle analysis (LCA).
The LCA is what really matters when talking about energy consmption/CO2 emissions. You’re probably familiar with the mother of all LCA debates: ethanol – does it produce more CO2 than gasoline over its lifetime, doesn’t it? It’s a hugely important question since the wrong policy decisions are being made right now by politicians who just don’t know. In the same sense as the ethanol lifecycle, you wouldn’t think about oil from Alberta’s oil sands without thinking about natural gas, water or strip mining, or about coal power without thinking mountain top removal.
So why is it that we only think about the lifetime of an energy efficient light bulb (in this article, a compact fluorescent light bulb, CFL) and not its dust-to-dust lifecycle?
It’s likely because we’re really only interested in our bottom line – the fact that energy efficient light bulbs use 13W instead of 60W, which could save us money. That, and because accounting for the total life cycle is notoriously difficult.
Keeping in mind the time requirements and expertise required to do a lifecycle analysis, I’m in no position to do one myself (and very few are), but luckily, I’ve found people who are.
The dust-to-dust story - production
If you have a compact fluorescent light bulb, take a look at it. It’s clearly more complex than your typical incandescent light bulb (your typical “in-efficient” bulb). The lamp tube of the CFL twirls in every-which direction, but there’s also complexity underneath: Coating the inside of the tube is phosphor, floating around inside the tube is ~5mg of mercury vapour (not much compared to a typical mercury thermometer which has around 250mg). There’s even a 24 component microchip (officially called the ballast) in every single CFL bulb! I tore one apart (carefully), this is what it looks like:
A picture of my prematurely broken CFL bulb. Every CFL has one of these microchips (balasts). This one contains 24 components.
Compare this to an incandescent bulb with a tungsten filament, is simple more beautiful?
The dust-to-dust story – lifetime
The lifetime of the compact fluorescent light bulb is where it really shines compared to the incandescent. An incandescent light bulb heats the tungsten filament by passing a current through it. This process sees 90-95% of the energy input going to heat and 5-10% going to light. In contrast, the CFL operates in a completely different way. Electricity is passed between two filament cathodes which stimulates mercury atoms to radiate ultraviolet radiation and heat. The UV radiation is transformed into light via the phosphor coating on the tube. With this process, about 25% of the energy input goes towards making light and 75% goes to heat.
The dust-to-dust story – end of life
When your CFL dies, it’s not recommended that you throw it out, this’ll just increase the chances of the mercury getting out into the open. The mercury can be recycled or disposed of properly and there are specific CFL recycling programs in place. For incandescent, no guide lines, just throw it in the trash.
The tally
Although difficult to come across, I found a life-cycle study comparing CFL bulbs to incandescent bulbs, written by Dutch researchers from the Technical University of Denmark. The total energy input for the production of a CFL light bulb comes to 1.7kWh compared to 0.3kWh for a single incandescent light bulb. The inputs are summarized in the figure below.
Energy input required to manufacture a CFL bulb, and incandescent bulb and 8 incandescent bulbs (a CFL bulb should last 8 times longer than an incandescent bulb)
Here's a summary of the embodied energy in a light bulb (all numbers represent energy in kWh):
* This assumes the CFL bulb operates for 8000hrs and the incandescent bulb operates for 1000hrs
** This assumes that the energy required to recycle a CFL bulb is equal to its production
Bulb for bulb, the energy “efficient” kind requires 5.7 times more energy to make than the incandescent bulbs, BUT, they last 8 times longer (1000hrs lifetime for incandescent bulbs vs 8000hrs lifetime for a CFL). So for every 1 compact fluorescent bulb that is made, 8 incandescent bulbs are made. Advantage CFL.
During the operation phase, the CFL needs 120kWh over its lifetime, whereas 1 incandescent bulb needs 60kWh or 480kWh for 8 incandescent bulbs. Advantage CFL.
The study that I cited above neglects the recycling stage, so I assumed here that it takes as much energy to recycle a CFL bulb as it takes to produce, 1.7kWh whereas an incandescent bulb is simply thrown out, and I assign 0kWh to the recycling stage of the incandescent. Advantage incandescent.
The break even point
Although CFL bulbs are supposed to last 8 times longer than the typical incandescent bulb, more often than not (at least in my experience), they seem to burn out prematurely. Given that they take more energy to make, bulb-for-bulb, this got me thinking. How long does a CFL bulb need to be running for until it breaks even (energy wise) compared to an incandescent light bulb? The answer’s in the graph below – 50hrs.
Break even point (energy wise) for a CFL bulb compared to an incandescent bulb. If the CFL bulb operates for 50hrs or more, then it will produce energy savings compared to the incandescent bulb.
Ever since I tore apart my old CFL bulb to find the microchip inside, I have been unconvinced that these bulbs provided any energy savings at all. Now I know that they do. Over their full lifetime, a compact fluorescent light bulb will consume 3.9 times less energy than an incandescent bulb. Although CFL's contain mercury themselves, their actual operation will introduce less mercury into the atmosphere than incandescent bulbs due to the fact that coal power plants spew out mercury. If your CFL bulb lasts longer than 50hrs, then they will indeed save energy over their entire lifecycle. CFL's, like many technologies, are ultimately only a stepping stone towards better, currently more expensive things, such as LED lighting, which promises to be even more efficient than CFLs.
Note: If you don't want to read all of this, here is the key point. If a CFL bulb lasts for longer than 50hrs, then the total life cycle energy consumption of the CFL will be lower than that of an incandescent bulb even though they are more complicated to make.According to the U.S. Department of Energy, lighting in the U.S. accounts for 22% of electricity consumption and costs American’s $58 billion a year. If every American home replaced just one light bulb with a compact fluorescent light bulb (your everyday energy “efficient” bulb), we would save $600 million per year in energy costs and prevent greenhouse gas emissions equivalent to 800,000 cars.
These numbers account for the life of the bulb though, not the entire life cycle of the bulb. The question of whether we can be more lighting efficient by using compact fluorescent bulbs needs an in depth analysis of how much energy is required to make and recycle the bulb. It’s actually quite complex. Here’s why.
When evaluating energy consumption or CO2 emissions of a technology, the full lifecycle of the product should be considered, not just its lifetime productivity. A proper analysis should include the CO2 emissions or embodied energy associated with all of the raw materials, all of the transportation and distribution, the operation and finally the recycling or decommissioning of the product. You’ll find a couple different names for this type of assessment popping up: energy return on energy invested (EROI), well-to-wheel (these two are typically used for fuels), dust-to-dust, cradle-to-grave or more correctly, life cycle analysis (LCA).
The LCA is what really matters when talking about energy consmption/CO2 emissions. You’re probably familiar with the mother of all LCA debates: ethanol – does it produce more CO2 than gasoline over its lifetime, doesn’t it? It’s a hugely important question since the wrong policy decisions are being made right now by politicians who just don’t know. In the same sense as the ethanol lifecycle, you wouldn’t think about oil from Alberta’s oil sands without thinking about natural gas, water or strip mining, or about coal power without thinking mountain top removal.
So why is it that we only think about the lifetime of an energy efficient light bulb (in this article, a compact fluorescent light bulb, CFL) and not its dust-to-dust lifecycle?
It’s likely because we’re really only interested in our bottom line – the fact that energy efficient light bulbs use 13W instead of 60W, which could save us money. That, and because accounting for the total life cycle is notoriously difficult.
Keeping in mind the time requirements and expertise required to do a lifecycle analysis, I’m in no position to do one myself (and very few are), but luckily, I’ve found people who are.
The dust-to-dust story - production
If you have a compact fluorescent light bulb, take a look at it. It’s clearly more complex than your typical incandescent light bulb (your typical “in-efficient” bulb). The lamp tube of the CFL twirls in every-which direction, but there’s also complexity underneath: Coating the inside of the tube is phosphor, floating around inside the tube is ~5mg of mercury vapour (not much compared to a typical mercury thermometer which has around 250mg). There’s even a 24 component microchip (officially called the ballast) in every single CFL bulb! I tore one apart (carefully), this is what it looks like:
A picture of my prematurely broken CFL bulb. Every CFL has one of these microchips (balasts). This one contains 24 components.
Compare this to an incandescent bulb with a tungsten filament, is simple more beautiful?
The dust-to-dust story – lifetime
The lifetime of the compact fluorescent light bulb is where it really shines compared to the incandescent. An incandescent light bulb heats the tungsten filament by passing a current through it. This process sees 90-95% of the energy input going to heat and 5-10% going to light. In contrast, the CFL operates in a completely different way. Electricity is passed between two filament cathodes which stimulates mercury atoms to radiate ultraviolet radiation and heat. The UV radiation is transformed into light via the phosphor coating on the tube. With this process, about 25% of the energy input goes towards making light and 75% goes to heat.
The dust-to-dust story – end of life
When your CFL dies, it’s not recommended that you throw it out, this’ll just increase the chances of the mercury getting out into the open. The mercury can be recycled or disposed of properly and there are specific CFL recycling programs in place. For incandescent, no guide lines, just throw it in the trash.
The tally
Although difficult to come across, I found a life-cycle study comparing CFL bulbs to incandescent bulbs, written by Dutch researchers from the Technical University of Denmark. The total energy input for the production of a CFL light bulb comes to 1.7kWh compared to 0.3kWh for a single incandescent light bulb. The inputs are summarized in the figure below.
Energy input required to manufacture a CFL bulb, and incandescent bulb and 8 incandescent bulbs (a CFL bulb should last 8 times longer than an incandescent bulb)
Here's a summary of the embodied energy in a light bulb (all numbers represent energy in kWh):
| CFL | Incandescent | 8 Incandescent bulbs | |
| Glass | 0.17 | 0.11 | 0.88 |
| Plastic | 0.68 | 0 | 0 |
| Electronics | 0.66 | 0 | 0 |
| Brass | 0.18 | 0.18 | 1.44 |
| Operation* | 120 | 60 | 480 |
| Recycle** | 1.69 | 0 | 0 |
| Total | 123.38 | 60.29 | 482.32 |
** This assumes that the energy required to recycle a CFL bulb is equal to its production
Bulb for bulb, the energy “efficient” kind requires 5.7 times more energy to make than the incandescent bulbs, BUT, they last 8 times longer (1000hrs lifetime for incandescent bulbs vs 8000hrs lifetime for a CFL). So for every 1 compact fluorescent bulb that is made, 8 incandescent bulbs are made. Advantage CFL.
During the operation phase, the CFL needs 120kWh over its lifetime, whereas 1 incandescent bulb needs 60kWh or 480kWh for 8 incandescent bulbs. Advantage CFL.
The study that I cited above neglects the recycling stage, so I assumed here that it takes as much energy to recycle a CFL bulb as it takes to produce, 1.7kWh whereas an incandescent bulb is simply thrown out, and I assign 0kWh to the recycling stage of the incandescent. Advantage incandescent.
The break even point
Although CFL bulbs are supposed to last 8 times longer than the typical incandescent bulb, more often than not (at least in my experience), they seem to burn out prematurely. Given that they take more energy to make, bulb-for-bulb, this got me thinking. How long does a CFL bulb need to be running for until it breaks even (energy wise) compared to an incandescent light bulb? The answer’s in the graph below – 50hrs.
Break even point (energy wise) for a CFL bulb compared to an incandescent bulb. If the CFL bulb operates for 50hrs or more, then it will produce energy savings compared to the incandescent bulb.
Ever since I tore apart my old CFL bulb to find the microchip inside, I have been unconvinced that these bulbs provided any energy savings at all. Now I know that they do. Over their full lifetime, a compact fluorescent light bulb will consume 3.9 times less energy than an incandescent bulb. Although CFL's contain mercury themselves, their actual operation will introduce less mercury into the atmosphere than incandescent bulbs due to the fact that coal power plants spew out mercury. If your CFL bulb lasts longer than 50hrs, then they will indeed save energy over their entire lifecycle. CFL's, like many technologies, are ultimately only a stepping stone towards better, currently more expensive things, such as LED lighting, which promises to be even more efficient than CFLs.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
I'm looking for a 12-volt white LED to replace my incandescent landscape bulbs with. Cost is not a factor, as the replacement bulbs from Home Depot or even online are about $5USD a piece!!! So, If I could get an LED for less than that - it's WIN WIN!
Also, I suck. I threw out an old CFL bulb in the trash the other day. Burn out from years of almost constant use ( security light ). I need to find a local recycle place, I dont think my neighborhood dump / recycling center does it.
Anyway - great work Ben.
Also, the CAPTCHA thing is more difficult than most. This is my third try.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Hrmm, here's something: http://www.lc-led.com/View/itemNumber/363
It's a 12V LED. It's $32 though (and not in stock at the time I checked). I haven't explored commercial LED's very much. LED's will definitely be a game changer in the lighting world, they are quite expensive at the moment though.
CAPTCHA thing: I made it a bit easier. I was getting quite a lot of spam...it seems to have died down a bit now though.
request...
Respected Sir/Madam,
my name is pradeep from bangalore , presently i have been a project on CFL bulbs but i am not able to get the information on about the energy consumed in preparing a bulb.So i request you to please guide me further.
Re: Compact Fluorescent Light Bulb Recycling
First off , great analysis Ben. I haven't been by theWatt in a while and things are looking great. As far as recycling CFL bulbs goes... I believe that Home Depot recently announced that they would recycle burnt out CFL's (at least that's the story in Ontario, Canada
Re: Compact Fluorescent Light Bulb Recycling
Hey Ryan, nice to hear from you and thanks! Home depot does have a recycling program: http://www.homedepot.ca/webapp/wcs/stores/servlet/DisplayTemplate?displa...
I wonder what percentage of CFL bulbs will realistically get recycled though? I'd bet it's pretty low.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Ben,
Thank you so much for the info. It really breaks it down. I wonder if CFLs are still efficient if they do not get recycled.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
From an energy stand point, they would be more efficient if you didn't recycle them because you wouldn't have to include that energy input. But, I suppose from an environmental point of view, since they contain mercury, it's best to recycle.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
How Many People Does It Take to Make a New Light Bulb?
http://www.time.com/time/health/article/0,8599,1721082,00.html
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
The heating effects that you mentioned are important, and need to be considered. In a simplistic analysis there are two basic scenarios to consider: heated rooms and cooled rooms:
Scenario 1: Heated rooms
If the bulb is used in a room that normally requires heating then all types of bulb, operate with 100% energy efficiency, because all of the input energy is converted to required heat. If the heating from bulbs is reduced by switching to CFLs then the primary heating system will simply make-up the difference in order to reach the thermostat temperature.
Consequently, in the best case where the heating is derived from in-the-room electric heaters, the overall operational energy saved by switching from incandescent lamps to CFLs, is zero; no energy is saved (the bulbs contribute less heat so the heater contributes more, to make-up the shortfall). However, if the heating system is of a type (such as a gas boiler) that vents large amounts of heat to the outside then the use of CFLs will lead to reduction in overall energy efficiency because the boiler will work more, causing greater amounts of heat to be wastefully vented.
Rooms that require heating should not, therefore, be illuminated with CFLs since no energy will be saved.
Scenario 2: Cooled rooms
If the bulb is used in rooms that normally require cooling then the heat generated by the lighting gives the cooling system more work to do. Reducing the energy used by lights reduces the total heat into the room and thus reduces the need for cooling.
In cooled rooms, therefore, swapping a 100W incandescent lamp for a 20W CFLs leads to an energy saving greater than 80W/h because the cooling system will also require less input energy. The exact amount saved depends how much energy is used (in KW/h) by the cooler to move 80W/h out of the room.
Even here, however, it is important to pay attention to the times when lamps and cooling are used. The greatest need for cooling is generally when the sun is brightest and the need for lamps lowest. At the times when the room is so bright that lamps are not switched on then it doesn't matter what kind of lamp is in the lampholder.
The aforegoing analysis is very simplistic, and most real world scenarios will be much more complex. Most rooms are not permanently heated or cooled, some are heated and cooled at different times. Many lamps are used in spaces that require neither heating or cooling. To evaluate any real-world scenario it would be necessary to know the duty cycles of the lights and heaters and coolers, and the overlap in operation. It would also be necessary to understand the feedback mechanism for the heater or cooler (i.e. understand the operational parameters for the thermostat). Another hard-to quantify factor would be human perception of temperature and comfort; are many small distributed heaters (aka lamps) perceived to create a more comfortable space than one centralized heater?
Nonetheless, despite the simplicity, I hope the above is sufficient to show that purely in terms of operational energy (i.e. ignoring embodied energy and disposal energy) the use of CFLs is not guaranteed to reduce energy use. My own view is that anybody who lives in a place where lighting and heating are often required together (e.g. places such as Canada, the northern states of the USA, northern Europe, northern Asia) should not use CFLs. People who live in places that tend to be bright possibly don't use enough lighting for it to be worth worrying about. People who living places that are well lit but often uncomfortably warm can reduce the temperature by switching to CFLs. Maximum potential energy-saving benefits are likely to be had in places that simultaneously require lighting and cooling.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Your numbers actually give a break-even time of 74.6 hrs per CFL: running an incandescent light for 1000hrs requires 60.29 kWh, running a CFL requires 3.38kWh per bulb+.015kWh/hr. The energy to run a CFL for 1000hrs is .015*1000=15kWh. 60.29-15=45.29kWH, so this is the amount of energy that can be devoted to producing CFLs to run for 1000hrs at the break-even point. 45.29/3.38=13.4 CFLs. 1000hrs/13.4CFLs is 74.6 hrs/CFL.
I assume that since there is such a large difference between either 50 or 74 and 8000, you considered your point to be made without finding a higher accuracy answer. I personally found your result of 50hrs to be so shocking that I had to check it.
Re: Compact Fluorescent Light Bulbs – Bad math
I'm sorry, but your calculations are simply wrong.
Your conclusion is that if a CFL gets used for 50 hours, it's paid for itself versus a comparable incandescent bulb. However, your calculations for establishing that metric are based on a fixed relationship between the lifetime of a CFL and that of an incandescent bulb: you say that the lifetime of a CFL is 8 times that of an incandescent bulb. If the CFL lasts only 50 hours, then that fixed relationship, itself, is wrong, and the cost factors used to compare the two types of bulbs are meaningless.
What we need instead is a fixed-cost factor for producing and disposing each type of bulb, and a statistical distribution of the ACTUAL lifetimes of a large enough number of bulbs to verify the lifetime figures. Only then will we have a useful metric for comparing the bulbs, a metric showing actual production/disposal costs per lighting-hour. I suspect that that analysis would not be so wildly in the CFL's favor.
I believe the DOE's figures for energy savings from CFL are also inflated. Residential use accounts for about 1/3 of our nationwide electrical use (see http://www.eia.doe.gov/emeu/aer/), and barely 9% of the average home's electricity gets used for lighting (see http://www.eia.doe.gov/emeu/recs/recs2001/enduse2001/enduse2001.html.) That means that at most, 3.3% of the nation's retail sales of electricity gets used for residential lighting. If CFLs genuinely use 1/4 the energy of incandescents, and ALL lighting gains that level of improvement, the net will be a 2.4% reduction in total national electrical sales. Note that this excludes all non-electrical energy usage; we're only talking about electric power generation. Note that the figure for residential electrical use allocates standard electrical generation and transmission losses to the residential sector, which skews the numbers way up. And note that the reduction of electrical use for lighting to 1/4 of current usage is wildly optimistic; not all current lighting is incandescent, and consumers report that you can't really replace incandescents for CFLs one-for-one.
Short version: switching from incandescents to CFLS won't make much difference.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
"What we need instead is a fixed-cost factor for producing and disposing each type of bulb, and a statistical distribution of the ACTUAL lifetimes of a large enough number of bulbs to verify the lifetime figures."
I've listed the energy costs of making and recycling 1 CFL bulb and 1 incandescent bulb. These lifetime numbers come from the study by the Dutch researchers. But I agree that it would be best to have more data on the lifetime of a CFL...the same goes for everything ever studied. I'll gladly update this when I get more data.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Ben, have you been able to find or do any studies regarding lifecycle costing of the LED lights vs CFLs?
My company is planning for purchase and replacement and is currently looking to make best value choices regarding the two. Our experimentation with LEDs shows their light is less impressive than the CFLs, which is pretty much identical to Incandescent for most folks.
So, from a value standpoint, any idea of break even time for LEDs ? Prices are high for them now, but the low wattage use might drastically reduce ROI time.
Thanks,
Frank
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Hi Frank,
I haven't seen anything like this for LED's. The analysis that I did above has nothing to do with cost though, just the energy requirement. I think LED's are quite a bit more expensive than CFL's right now and much more expensive than incandescents and for them to be even comparable in terms of cost (as in $ not kWh), then you'd probably have to be using them 24hrs/day, 7 days a week. I know that LEDs are cost effective when they are being used in tunnels since tunnels need constant lighting.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Ben:
You have an interesting article here, but I'd love to see how CFL lamps compare with dimmers. CFLs can't be dimmed, often have poor colour rendering, and the ambient temperature affects the lifespan and lumen light output greatly of CFLs. Dimmers on the other hand seem to save energy without compromises.
Dimmers probably cost a little more to manufacture than a basic toggle switch, so only the difference in energy between the two would need to be considered.
Dimmers will extend the incandescent bulb life anywhere from 2 to 20+ times in length, depending on the amount dimmed. From personal experience, I have not had to replace a single incandescent bulb in over 4 years, and I use the dimmer every day. I figure I have the lights dimmed to 70% of max output on average.
Dimmers save energy at a nearly linear rate. i.e. dimming 50% saves 40% energy.
With a dimmer, I can adjust the light level to match the task I am doing, so I always have the convenience, safety and ambiance. Lutron Electronics seems to be a leader in dimmers and I wonder how they measure up to the CFL? I love saving energy, but at the same time, Lutron makes some fantastic products that really tempt me!
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Hi Eric, Ben,
Eric, dimmable cfls are now available! See here for the article and link to buying them:
http://www.thegreenguide.com/blog/lighten-up/886
&
http://www.thegreenguide.com/blog/freshfinds/340
1. Yes, dimming does save energy.
2. Dimming CFLs saves even more.
From a performance standpoint, I replaced all my bulbs with CFLs about 2-3 years ago. We can no longer tell any discernable difference in lighting, and are very happy with the lumen output. We live in Colorado, and our electric bills are consistently less than my comparable peers. Further, I've only had one burn out,and can attribute that to a bottom of the barrel brand I tried. Most of mine came from Home Depot and are major brands.
Finally, I have an article at work showing LEDs lights have a huge payback and our customer, the military, is probably going to be putting them into new construction and some retro-replacement. They no longer replace burnouts with any incandescent, only CFLs.
Thanks for providing the valuable information.
-Frank
Re: Simple Improvement
Make the CFL from to parts glass tube and the rest if 1 part is gone it can replaced with out the other.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Ben,
I have recently tested 5 different dimmable CFLs and have a range of test data on each. If you think it is of interest to your readers (listeners) I could try to package the information up in a more usable format.
Thanks
John C. Briggs
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Thanks for the contribution to an evolving debate of CFL and incandescent light “bulbs”.
In this analysis of "energy input required during production", the components listed are: glass, plastic, electronics, brass, operation, and recycle; not mentioned is the cost of mining of rare earth phosphors; these phosphors are an essential component of all fluorescent lamps and compact fluorescent lamps (CFL). It is the mixing of the phosphors which coat the inside surface of the bulb that provides the color and quality of light that is acceptable for use. The mining of these materials surely has significant impact on the environment and should be considered into the energy input equation.
Also not included in the analysis is the production and shipping of CFLs versus incandescent lamps.
On a subjective level, sometimes compact fluorescent lamps (CFL) are too bright, especially in the later evening hours when lower light levels are more conducive to relaxing. Dimming ballasts are available for CFL pin-base configurations, and they are expensive for the user. (I’m not aware of screw-base dimming ballasts –but they could be out there).
Lamp life seems to be the deal breaker in this analysis. However, the life of incandescent lamps are increased significantly with the use of “dimmer” switches; also available are desk/credenza dimmers which can be used with any incandescent table or floor lamp. I have lived in my condo for six years and last week I replaced my first light bulb – all my light fixtures are on dimmer switches.
Since the writer didn’t include the mining of rare earth phosphors, the production and shipping of CFLs versus incandescent lamps, and the use of dimmer on incandescent lamps in the analysis, I disagree with the boxed note at head of this page: “Note: If you don’t want to read all of this, here is the key point. If a CFL bulb lasts longer that 50hrs, then the total life cycle energy consumption of the CFL will be lower than that of an incandescent bulb even though they are more complicated to make.”
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
Screw based (Edison bulb) dimmable CFLs are available. These also save electricity when they are dimmed. So a dimmed CFL is much more efficient than a dimmed incandescent.
However, there are limitations to dimmable CFLs. They are expensive (~US$12), physically larger than non-dimmable CFLs, some have terrible dimming characteristics, and the slow start of CFLs make dimming a challenge. Basically the bulb turns on at about 50% brightness and in 30 seconds achieves 90% brightness (for the good bulbs that is, bad bulbs take longer). So if you want the bulb dimmed to 50% brightness, you have to turn it on, wait 30 seconds, and then dim it.
If you want to try dimmable bulbs, I suggest you start with
GE 89623 DIMMABLE CFL LIGHT BULB 60 watt
GE 89624 DIMMABLE CFL LIGHT BULB 100 watt
These are the best of the four brands that I have tried. But personally, I don't recommend dimmables CFLs at this time. Note that I have nothing against CFLs and personally use all CFLs and LED lighting in my home.
I find the whole CFL debate and interesting study in human nature. We humans are greatly opposed to change. There must be some Darwinian value in this. Perhaps resistance to change is a real survival skill that we learned long ago when we lived in caves. We will latch on to the smallest scrap of evidence and use it as an excuse not to change.
The CFL excuse that always amuses me is "CFLs have mercury and therefore I will not use them". True, mercury is a serious toxin and should be managed carefully. But what amuses me is that people act like this is a new problem. People go to work every day, or to school, or to church, or to a public building illuminated by fluorescent lighting containing mercury. No one ever notices that these are fluorescent bulbs versus incandescent bulbs (unless they are flickering). No one thinks about the mercury. They are content with the light they have. But when it comes to their own home, all of a sudden, mercury is this enormous problem. We have been managing the mercury issue for years with commercial buildings, we can also manage it in our homes.
For me, I have reduced my electricity consumption from 12,000 KWH/year down to 3800 KWH/year and CFLs were an important piece of that. This saves me US$1600/year and I have little doubt that there are significant environmental benefits as well.
I would like to encourage everyone to find at least one place in their homes where they can try a CFL bulb or two. This might be in some non-critical place like a hallway light that is often turned on, or outside lights that are often left on all night.
Re: Compact Fluorescent Light Bulbs – A Tale From Dust to Dust
It has been my experience that cfl's fail prematurely due to heat build-up. I noticed that I had a high failure rate in certain fixtures in my home, but not others. Generally speaking, I had a high failure rate in fixtures that place the cfl's electronics above the fluorescent tube, and in those that trap heat inside. After correcting my "fixture" issue, my cfl's tend not to burn out. Having corrected this premature burn-out problem, my cfl's do indeed save energy, cutting my electric bill and having a positive effect on the environment. I've written more about this on my blog: http://solarjohn.blogspot.com
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