Dim bulbs who discuss energy efficiency

Dim bulbs who discuss energy efficiency

The Internet can certainly be a source of cheap amusement. I’m not talking about sites hosting episodes of TV shows or videos of pratfalls. At least for me, the more humorous material comes from comments posted about news items. Comments can get particularly funny when the original item was written by someone who poorly understands the event they’re reporting on. It is a little like the clueless masses kibitzing on the writings of the uninformed. Especially comic examples can be found in the area of energy issues.

One such incident comes to mind from last year when The Institution of Engineering and Technology in the UK published results of a study on compact fluorescent lamps. One finding in the study made headlines at both the BBC and the Telegraph: that CFLs lose about 20% of their brightness over their operating lives.

The tone of the coverage was that of a scandal. Of the report, the Telegraph said, “It concludes that consumers are being routinely misled about the efficacy of low energy light bulbs, or compact fluorescent bulbs as they are technically known.” Quoting the report author, the Telegraph further screeched, “There is a big difference between what most bulbs’ packaging promises and what the reality is. It’s no wonder so many consumers are dissatisfied with the bulbs.” At the BBC, writers quoted the author as opining that “packaging claims about the power of the bulbs did not live up to what they delivered in terms of people’s perceptions of light.”

Judging by the comments that ensued, the report seemed to bring a lot of UK conspiracy theorists out of the closet, as well as a number of people who thought they knew what “efficacy” meant but didn’t. Claimed one, “The whole CFL thing is another snake-oil con like HDTV, engineered to boost the manufacturers’ profits by taking advantage of the general public’s lack of technical knowledge and gullibility.”

I agree with this poster’s opinion of the public’s lack of technical knowledge, but not for the reasons he might think. The key piece of information missing from both initial news reports and the barrage of silly comments was that the light output of ordinary fluorescent tubes also falls off by about 20% over their lifetime. That’s not a secret concealed from public view. After all, fluorescent tubes and CFLs share the same wear-out mechanism: The phosphor on the tube becomes progressively less efficient at converting emitted UV to visible light, and the small amount of mercury in the tube gets absorbed into the glass so it is unavailable for generating light.

To get some specifics, I checked with lighting engineers at GE Lighting, which holds a big chunk of the market in CFLs. They explain that most CFLs follow EnergyStar specs which dictate that after 1,000 hours of use, CFLs must put out at least 90% of the light they put out after 100 hours of use. When there is 40% of their projected life left, it must put out at least 80% of its 100-hour level. Fluorescent tubes aren’t rated in quite the same way, but their light output over time is similar. Even so, say GE engineers, a 10% falloff in light output is unnoticeable to humans. And it would be hard for people to notice even a 20% falloff.

Which means the screaming Internet headlines and resulting outrage was over a change in light level that, in all probability, no one can discern. As a source of entertainment, it beats I Love Lucy reruns.

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