There has been a lot of buzz (literally and figuratively) about CFL’s lately. These “compact fluorescent lamps” or bulbs are supposed to save electricity, and hence save the planet. Are they the panacea that they are claimed to be? I’ve used CFLs in some applications for about five years, so I feel qualified to comment.
The first issue I’ll discuss is energy savings.
Because they operate more efficiently, they are claimed to produce about the same amount of light (lumens) as a conventional bulb while using only about one quarter the amount of electricity. While this is true, it does not tell the whole story.
A CFL takes many times the energy to manufacture compared to a conventional incandescent bulb. If you’ve ever opened up the base of a CFL (which must be done carefully to avoid damaging the fluorescent tube portion of the lamp and releasing the highly toxic mercury it contains), you have seen a treasure trove of electronic components. All of these components require energy to manufacture. I would be very interested to find out exactly how much energy is required to manufacture a CFL versus an incandescent lamp.
Almost all of the power consumed by any light bulb is dissipated as either light or heat. During the cooling season, the cooler-burning CFLs, in addition to consuming less power, also reduce the amount of energy you have to spend on air conditioning. However, during the heating season, since CFLs produce less heat, your home’s heating system has to make up the difference! I’ve never tried to calculate the difference in BTU output between CFLs and incandescents for an average sized home where all or most of the bulbs have been switched to CFLs, but the difference would be quite substantial. Just a dozen CFLs would consume about a kilowatt less energy for the same light output as the same number of 100-watt incandescents! To put that in perspective, it’s actually quite amazing how much heat is generated by just a single 100-watt incandescent bulb, a PC and a monitor, which together can consume 300 to 400 watts of power. The heat produced is enough to substantially raise the temperature in a small to average size room.
Interestingly, I’ve never seen any discussion of the fact that using CFLs will actually increase the cost of heating your home. If your home has electric heat, you would probably still use the same number of killowatt hours of electricity overall, but the increased energy used by your heating system will largely negate the savings you are expecting from the CFLs. If you use another fuel, say natural gas, you will need additional therms (cubic feet of gas) to make up for the reduced heat output of the CFLs. If you live in an area where most of the year is heating season, such as the northeast United States, then your heating costs will increase proportionately. Also, since the indoor versus outdoor temperature differential is generally much greater during the heating season than the cooling season (around here, the winter indoor/outdoor temperature differential is about two times greater than the summer differential). This means that the CFL’s reduced load on your air conditioner during the summer is going to outstripped by the increased demand on your furnace in the winter.
The bottom line is that your thermostat really doesn’t care whether the heat comes from your light bulbs, your computer, your oven, your furnace or you. If it’s 20 degrees outside, and you want it to be 70 degrees inside, that energy is going to come from somewhere.
Applications where CFLs can not be used
Compact Fluorescent Lamps can’t be used with a dimmer, unless they are one of the newer types specifically designed for dimmer applications. If that is the case, the packaging and the bulb will clearly state that it can be used in a circuit with a dimmer.
CFLs should never be installed in a fixture that encloses the bulb without ventilation. While conventional bulbs can withstand very high temperatures (with some decrease in bulb life), CFLs will quickly self-destruct if they get too hot.
CFLs should be operated base-down. If operated in an inverted, base-up orientation, the heat generated by the fluorescent tube will rise, heating the bulb’s base containing the electronics, shortening the bulb’s life.
Like any fluorescent bulb, CFLs don’t work well in low ambient temperatures. Even when used indoors, if the air temperature is, let’s say, 50 or 60 degrees Fahrenheit, a CFL will operate at significantly reduced brightness until it has warmed up. In outdoor applications, I suspect they will not start, or illuminate at all, below a certain temperature. You can buy conventional fluorescent lighting fixtures that have special ballasts for cold-weather starting, but I don’t know if CFLs are offered that way also. I think there is also the danger that a CFL will destroy itself trying to start when it’s too cold.
RF Interference from CFLs
Unlike conventional incandescent bulbs, the electronic circuitry (electronic ballast) in CFLs generate radio frequency interference (RFI). Depending on where they are installed, this may not be a problem, or it may be so severe, you will be unable to use CFLs in some applications.
They will interfere with most radio receivers, particularly AM (Amplitude Modulation) radios. You may be able to mitigate this by moving the radio farther away from the CFL, and/or plugging the radio, TV or other device receiving the interference into a different outlet or branch circuit. CFLs will render some remote controlled devices inoperable. I use home automation remote control devices sold under the X-10 brand name. The X-10 modules will simply not work anywhere near a circuit with an energized CFL. They produce so much RFI that they blind the X-10 receivers. Worse yet, some X-10 modules will randomly turn on and off due to the noise coming down the AC line (I’ve also seen this problem when trying to use X-10 modules to control computers which use switching mode power supplies). The closer a CFL is to an X-10 module, the more problems you will experience. I suspect this is true to varying degrees, for any brand of CFL, and any brand of RF-based remote control device.
If you have a burglar/fire alarm system that uses wireless modules, such as motion detectors or door/window sensors or smoke detectors, I think that the RFI generated by some CFLs might cause the alarm system to malfunction. Since this could create a dangerous situation, use CFLs with caution in these environments.
I’ve noticed that CFLs, like most other fluorescent lighting, can produce some acoustic noise. Conventional fluorescent lighting fixtures and ballasts carry acoustic noise ratings, which tell you how much buzz or hum they generate. I’ve never seen an acoustic noise rating on a CFL package.
Lighting qualities of CFLs vs incandescents
There is the issue of reduced light output in low ambient temperatures that I previously discussed. I’ve also noticed that new CFLs seem to operate at reduced brightness until they are “broken in”.
Not all light is created equal. Different light sources produce different color light, or more specifically, light in a different part of the visible spectrum. This “Color temperature” is an issue for some people. Experienced photographers know how important the color temperature is, and how it affects the way things appear under different lighting sources. Some people dislike the light produced by fluorescent bulbs, and prefer incandescent lighting. If this is important to you, check the CFLs before you buy. Some packaging will indicate the color temperature of the bulbs.
Mercury content of CFLs
I think that the shift from incandescent bulbs to CFLs might be creating a bigger problem then it solves. There is a small amount of mercury in every fluorescent bulb of any type, including CFLs. I think mercury is added to the inside of the fluorescent tube to make it electrically conductive.
Now, mercury is a really nasty element, environmentally speaking. I avoid eating a lot of certain types of fish, such as tuna, because of mercury contamination. Mercury poisoning, like lead poisoning, is forever. Mercury is forever. Mercury contamination of the environment as well as indoor mercury contamination are so dangerous, I don’t even think you can buy thermometers containing mercury any longer. Why would you willingly buy a product containing mercury (CFLs), when there are alternatives available (incandescent bulbs)? Are the advantages of CFLs so great that it’s worth the environmental damage they are causing?
Actually, this problem is larger than just Compact Fluorescent Lamps. Flourescent lighting fixtures are ubitiquous in commercial buildings, at least in the United States, and to a lesser extent, in residential buildings. Virtually all of the used fluorescent bulbs from these fixtures go into the trash stream. Then there’s also Mercury Vapor Lamps which are used in commercial applications such as street lighting. How many tons of mercury are being put into the environment every year due to discarded fluorescent and other mercury-containing bulbs?
Starkist doesn’t want tuna with good taste; They want tuna that doesn’t contain mercury. If fish could talk, which type of bulbs do you think they would tell us to buy?
Obviously, even incandescent bulbs can start fires. The higher the wattage, the hotter the bulb, and the greater the danger. Some types of bulbs, such as quartz lamps, which are physically very small but very high wattage (up to at least 500 watts), pose a particular fire risk.
There is less of a chance of a CFL igniting nearby materials because they run cooler, but is there a new type of fire risk posed by CFLs? I’ve already had the electronics inside a CFL burn up and stink up the house with that characteristic “burning-electronic-component” odor. Can the electronics or plastic shell of a CFL ignite and start a fire? I would think they could. This is not a problem withincandescent bulbs, since they are just glass and metal… materials which don’t support combustion.
Claimed vs actual bulb life
Can you believe the claims made about the life of CFLs versus incandescent bulbs? In my experience, they do last longer than incandescents, but nowhere near the 10 to 12 times longer claimed.
I would estimate that they last three to four times longer than incandescent bulbs. I’ve bought some multi-packs of incandescent bulbs for as little as 25 cents per bulb. While the prices of CFLs vary greatly, I would guesstimate that they cost between two and four dollars (US) per bulb. I’ve seen single packs of CFLs selling for much more, perhaps $9.00 for a bulb. So, I’ll say they cost between ten and twenty times as much as incandescents. That’s a huge differential. It’s way out of proportion to the increase in life over incandescents. Will the claimed energy savings over the lifetime of a CFL (see my section about energy savings earlier in this article) be enough to offset the price difference and justify the environmental damage from mercury?
The Bottom Line
You’ll probably do more harm to the planet by jumping into your gas-guzzling, ozone-depleting, greenhouse gas-producing SUV and driving down to the Home Depot to buy a pack of Compact Fluorescent Bulbs, than if you just kept using incandescent bulbs.
Turn off the lights when they’re not needed. Make sure your next car gets better gas mileage. Does everybody have to be driving a truck? Don’t travel unnecessarily, whether it’s to the grocery store or to Tahiti. Convince your employer to let you telecommute, at least part of the time. Recycle whatever products you can recycle. Insulate your home. Use rechargeable batteries instead of throw-aways. Doing some or all of these things will have a bigger impact than just changing a light bulb.
For more info, I recommend this extensive article on Wikipedia about CFLs.
When I continue, I’ll discuss…
- Cost of CFLs vs Incandescent bulbs
- Recycling of CFLs and other fluorescent lamps