We've been looking in to compact fluorescent bulbs (CFLs) to reduce energy consumption for lighting. Here's what we've learned so far.
Manufacturers say that a 13-18 watt CFL produces light equivalent to a 60w incandescent bulb, an 18-22w CFL is the equivalent of a 75w bulb, and a 23-28w CFL is the equivalent of a 100w bulb. This is based on the "lumens" rating on the side of the box.
In real life, CFL equivalent replacements do not seem quite as bright as incandescents, so you might end up replacing a 60w equivalent with a 75w equivalent and so forth. (The "swirled" designs seem to give off brighter light than the CFLs with a traditional "bulb" design.) But overall, CFLs reduce energy use for lighting by 60%-70%.
Color temperature makes a big difference. The lower the color temperature, the more the light resembles the "warmth" of incandescent bulbs we are all used to (that may sound backwards, but that's how it works). Not all CFLs list the color temperature. The GE "Soft White" has a pleasing, almost incandescent look, while the similarly named Sylvania "Soft White" has a cooler, harsher "fluorescent" look (although some might prefer it for truer color rendering or easier reading).
We found some Sylvania "Warm White" 13w (60w replacement) CFLs at Lowes that have very pleasing light, and their small size allows them to fit most fixtures. The color temperature is listed as 2700K (as compared to their "Daylight" CFL which is listed at 6500K and seems much "harsher".) The 13w "Warm White" CFLs came in a contractor's box of 12 for $27, which is a pretty good deal. They are rated at 800 lumens with a lifetime of 10,000 hours, as compared to a standard GE "Soft White" 60w incandescent, which is rated at 840 lumens with a life of 1000 hours.
Because of their long life and lower energy consumption, CFLs can result in significant savings over the lifetime of the bulb relative to its cost. Manufacturers are quick to point this out, with claims on the packaging of $36+ in energy savings over the life of a 14w (60w equivalent) up to $61 for a 23w (100w equivalent). Your mileage will probably vary.
All of the CFL bulbs we tried came on quickly (some instantly), none exhibited any flicker, and none caused any audible humming or other noise. Some take a little longer than others (only a few seconds in most cases) to warm up to full output. It appears that the latest CFL designs have eliminated most of the previous complaints, although site wiring problems can be an issue according to manufacturers.
Most CFLs do not work with dimmers. Manufacturers say it will shorten the bulb life and it voids the warranty. There are special bulbs that work with dimmers, but they are not widely available. If the package does not say the bulb is compatible with dimmers, it probably isn't. (Look at the fine print on the base of the bulb.) We are still looking for a local source for "dimmable" CFLs, as most of our fixtures have dimmers. CFLs are also not intended for use with most photocells and timers.
One thing that is not talked about much is that CFLs emit more ultraviolet (UV) light than an incandescent bulb, which produces virtually none. Light in a CFL starts out as UV from excited gases, and is made visible by phosphors coating the inside of the tube/bulb. Incandescent light is mostly infrared emitted by heating the filament to super high temperatures (leading some to call them "heat bulbs" instead of "light bulbs"). Most of the UV from a CFL is filtered out in the conversion, but there is still some.
Manufacturers say, however, that there is no health risk and that eight hours of exposure to CFL UV is about the same as one minute in full sunlight. But, photographs, artwork, some fabrics, and some photoreactive chemicals used in furniture finishes are susceptible to degradation from any increased levels of UV over time. So this is something to consider.
The Mercury Problem
Finally, CFL critics like to remind you that CFL bulbs contain mercury, a highly toxic pollutant. This is true. The typical CFL bulb contains approx. 5mg of mercury. (Manufacturers are working to reduce this. Phillips is said to have developed a bulb that only has 1.5mg of mercury.)
If a CFL bulb is broken, special care must be taken to properly clean up and dispose of the remnants to prevent health risks. Further, CFLs must be recycled or properly disposed of to prevent the mercury from escaping into the environment. Here are the federal government guidelines for CFL disposal and cleanup.
What the critics forget to mention, however, is that coal-fired power plants are a major source of mercury pollution. Further, most of this mercury is emitted into the air, and is thus not contained or containable. Mercury in a CFL is already contained unless it is broken, and if properly recycled is fully containable.
We did some rough calculations to determine the mercury pollution impact of CFL v. incandescent bulbs. We used TVA's Kingston plant as an example. It generated 10,161,530 MWh in 2005, and released 643 pounds of mercury into the environment. This works out to 28.7 mg of mercury per MWh.
Based on this, a 100w incandescent bulb operated for 8000 hours (the rated life of a typical CFL) causes 23mg of mercury pollution. An equivalent 23w CFL bulb will cause 5.3mg of mercury pollution. Assuming the bulb is crushed and dumped in a landfill releasing its 5mg of mercury into the environment, the CFL will cause 10.3mg of mercury pollution over its lifetime as compared to 23mg of mercury pollution for an equivalent number of incandescent bulbs, a reduction of 12.7mg or 55%.
55% sounds like a lot. But according to DOE estimates, residential power usage is about 35% of the total, and lighting in the average home accounts for about 9.4% of the energy used. Considering that about 64% of TVA power is generated from coal v. hydro and nuclear, the net reduction of mercury emissions if every TVA residential customer switched to CFL bulbs would be about 6 pounds at the Kingston plant, about a 1% reduction. System-wide, this would be a reduction of about 52 pounds annually.
52 pounds doesn't sound like much mercury (even though it's thousands of lethal doses) but it's something. Multiply that for every power system in the U.S. and it adds up.
So CFLs won't save the planet, but they might put off its demise for a month or two.
Plus, we should take pollution controls wherever we can get them. If residential use of CFLs reduced overall coal-fired power consumption by 1.5%, the system-wide reduction in TVA emissions would be 2865 tons of NOx (nitrogen oxides that cause ozone and smog), 6900 tons of SO2 (sulfur dioxide that causes acid rain and harms plants and stream ecology), and 1,575,000 tons of CO2 (a greenhouse gas that contributes to global warming) annually (2005 figures). Increased commercial usage of CFL would result in even more reductions.
Back to the CFL mercury problem, a couple of things need to happen right away:
• Consumers need to be educated on proper disposal and cleanup. The packages we purchased do not mention this prominently or at all. One directs you to a website. There should be prominent warnings about health risks and instructions for proper disposal and cleanup on all CFL packaging.
• Local public works officials need to incorporate CFL collection, recycling and/or disposal into their waste management programs.
• Big-box retailers who sell more than 100 CFLs per year (or some other arbitrary figure) should be required to provide on-site recycling centers.
UPDATE: I mentioned that dimmable CFLs are hard to find. I couldn't find any locally, but a good source on the internet for dimmable CFL bulbs is TopBulb.com.
The bulbs are a little expensive ($24 ea. for the ones we bought), but they work and they will pay for themselves in energy savings over the 10,000 hour rated life of the bulb (if they last that long).
We got 15w (2700K color temp.) replacements (made by Technical Consumer Products, also known as "Springlamp" brand) for two 60w kitchen lights. Actually, we were using 54w long-life bulbs, so the 15w CFLs are a little brighter. They work fine with the dimmer but won't dim as low as incandescent (the CFL dimmable range is 100% to 20%).
It's odd that the package says "DIMMABLE" all over it, but the fine print caution says "not for use with dimmers". I called TCP to ask about this, and the customer service person agreed this was odd but said no one had ever asked about it and as far as they know it's just a misprint on the packaging. What I do know is they work fine with our dimmers.
Another good online source for less expensive (with lower lifetime rating) CFL bulbs is EnergyFederation.org.
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