CFL hell October 11, 2007
Posted by spacemom in : It ain't easy being green , trackbackOh yes, we are in CFL hell. And I don’t mean deciding which why anyone would name their team after a dove.
No, I mean Compact Fluorescent Light bulbs. Those CFLs… When Jay and I first started dating, we were, um, working together, yeah, together. That’s the ticket. And we were working on, observing. One of the first things he noticed was that my night vision sucks big time. However, as we have been together so ling, I can tell you that I have incredible motion detection. In other words, my eyes report to my brain much faster than the average person, so a rapid change in position registers, but at night, I don’t get enough photons to my brain so everything looks dark.
What does this have to do with CFLs? Well, the rapid reporting (I call it readout) means that I can see the flicker of the magnetic ballast in most fluorescent lights. I required a flat screen LCD monitor at work because the refresh rate of the CRT monitors and the flicker of the CFLs would compete for attention and I would develop migraines. It was hard to convince co-workers to turn off the lights, especially with the early sunsets on the East Coast.
Some CFLs are good and I can’t see the flicker. Others are not so good. Also, I am having a hard time finding the RIGHT CFLs for our house. You see, the CFLs come in different "colors". They report this with a color temperature. For example, the Sylvania ones that we bought, had a color temperature of 3000K. The GE ones we bought we 2700K. The cooler, the redder the light. The temperature means that the color from the light bulb, if measured by the brightness (intensity) vs the color of the light (wavelength) would match a black body of that temperature.
With me so far? Okay, from my years of indentured servitude Grad School, I can tell you that a 3000K and a 2700K blackbody aren’t that different. Really. But here comes the trick. There is another measure for CFLs called the CRI.
Here’s one definition of CRI:color
rendering index (CRI)
A measurement of the color shift an object undergoes when
illuminated by the light source, as compared to a reference
source at the same color temperature. Color rendering is measured
on an index from 0-100, with natural daylight and incandescent
lighting both equal to 100. Objects and people viewed under
lamps with a high color rendering index (CRI) appear more
true to life.
Okay, now if you have EVER done any graphing in your life. You might stop and wonder about this. There are two differing statements here: 1) CRI is a measurement of the color shift and 2) is a measure of how true to life a color is.
We bought two different CFLs this week, the Sylvania(3000K, 23W, CRI=82) and GE(2700K,26W,CRI=82). These both replace a 100W bulb.
The Sylvania was clearly more blue. And it flickered. Badly for me. Jay could not see the flicker. To me, the CRI was saying "Hey! We match the blackbody at about 82%! Go us! but we miss on the red end!"
This is the only thing I can think of since both bulbs claimed to be 82 on the CRI scale. The GE light was far more red, giving that warm tone I expect from a bulb. These flickered only at low power (we have them in a 2 way light, we need the light to have full power for the bulbs to not flicker).
We are taking back all of the Sylvania bulbs that Jay bought. They suck. For us. They are too blue, too flickery…ugh.
We are trying to be more green, but it is hard sometimes.
Next on the green path: solar power. Yes, we are seriously considering solar panels.
Comments»
Where do I begin?! You have connected flicker with color temperature and CRI, when it has to do with the ballast, not the lamp. And you compared apples to oranges when it came to the Sylvania and GE lamps of different color temperatures.
Please do a little more research on the subject of flicker before bad mouthing all CFL’s.
A good start is with your local Chapter of IESNA (Illuminating Engineering Society of North America): www.iesna.org
Further to what Sharon has pointed out, the flickering is caused by a magnetic ballast. Most modern CFL’s have electronic ballasts, which eliminate the flickering.
Also, color tempurate is actually measured in Kelvins or mireds (1 million divided by the color temperature in kelvins). “Color temperature is a quantitative measure. The higher the number in kelvins, the “cooler”, i.e., bluer, the shade. Color names associated with a particular color temperature are not standardized for modern CFLs and other triphosphor lamps like they were for the older-style halophosphate fluorescent lamps. Variations and inconsistencies exist among manufacturers. For example, Sylvania’s Daylight CFLs have a color temperature of 3500 K, while most other lamps with a “daylight” label have color temperatures of at least 5000 K. Some vendors do not include the kelvin value on the package, but this is beginning to change now that the Energy Star Criteria for CFLs is expected to require such labeling in its 4.0 revision.”
You are correct however in noticing that there are large differences among quality of light, cost, and turn-on time among different manufacturers, even for lamps that appear identical and have the same color temperature.
CFL lamps with attached ballasts and screw bases are available in so many combinations it is no doubt confusing. In efforts to promote the efficacy and life v. common incandescent lamps for consumers, manufacturers run out of real estate on the packaging (especially since we have to use at least two languages).
IF the lamp you pick has a “magnetic” ballast it will run the lamp at 60Hz and MANY people can perceive flicker, especially peripherally, at this frequency. Magnetic ballasts, in my opinion, are usually the culprit if someone dislikes fluorescent. When the ballast is “electronic” and all is right w/ the application (no interference from a timer or occ. sensor or illuminated switch, etc.) then the flicker situation is rectified. W/ electronics the lamps are operated at very high frequency so their phosphors don’t perceptibly discharge between cycles.
Lamps don’t always flicker on on off when they’re first started. This can go either way. Sylvania’s electronically ballasted models are “instant on”.
In your case, it could easily be that since the magnetically self-ballasted CFLs are cheaper, that is what your local retailer opted to offer. If your sensitive to flicker you will want to make sure you’re getting the electronic types.
As far a lamp color preference, this is subjective and if you like the “warm” tone of the 2700K, just look for that on future purchases. We make some wattages/sizes is 2700K, 3000K, 3500K, 4100K and 5000K so there is something for everyone.