On CFLs, Annoying Nomenclature, and Further Reasons to Hate Home Depot

My brother-in-law, Phil, is an energy consultant.

No, he does not sell overpriced sports drinks or teach you how to focus your chi through the power of crystals. Phil is a real energy consultant, advising corporations, governments, and other minor entities on how to lessen their consumption of electricity and heat.

Having recently moved into an apartment where the rent does not include utilities, I am now starting to care about such things, too. Well, electricity, anyway. I've got more than enough heat these days.

While browsing staples.com for some office supplies, I therefore thought to take a look at what they had to offer in the way of compact fluorescent light bulbs (lightbulbs?), or CFLs.

Despite their unfortunate side effect of causing spell-check dilemmas, not to mention devaluing the brand identity of the Canadian Football League, CFLs have become all the rage lately. As I'm sure you've heard preached, CFLs mean big savings over the long run. In case you haven't:

<sermon>

For an equal amount of light, a CFL costs about one-quarter as much to run per hour as a standard incandescent bulb. They also last about ten times longer. Over the life of the CFL, this amounts to tens of dollars saved, just for replacing one bulb. Replace the bulbs in several of the heavily used lamps in your house, and we're talking a C-note in your pocket at the end of every year.

It's also nice to contemplate the possibility of everyone buying just a few each, worldwide, and the consequent mountains of coal that wouldn't have to be dug up and burned to make all that electricity.

</sermon>

The price for CFLs on staples.com seemed a bit steep, so just to check, I looked next at homedepot.com. They were asking the same, about eight bucks apiece. Having had a fair amount of scientific training, I leaped to a conclusion from these two bits of data, and fired off a quick screed to my father. We had been in a hardware store last week, and did not pay sufficient attention to a display of CFLs -- on sale for a buck apiece -- and I laid the blame mostly at his feet.

Having vented, I looked around some more, and as he more calmly replied in his email, it is of course true that CFLs can be had for considerably less. The web site bulbs.com, for example, lists them for three to five bucks apiece, depending on brightness, brand name, quantity ordered, and several other less comprehensible factors.

So, the first thing I learned is that Home Depot is still scamming the public. Quite apart from the evil that these big boxes represent, with their killing off of the local hardware stores, their prices across the board are not as good as their mind-numbing commercials suggest. In fact, they tend to be quite expensive for mundane things like light bulbs.

The second thing to investigate was one of the more murky specs that bulbs.com lists for all CFLs. Do you know the difference between otherwise identical bulbs, if one is a "2700K" and the other a "5000K?"

If you do, give yourself a nice round of applause. I didn't have a clue. The only thing I could think was that "K" meant "thousands." Since that seemed unlikely, I brushed aside the cobwebs, thought back to high school chemistry, and remembered "kelvins." Remember those? Something to do with temperature? Yeah, degrees or something, right?

In one of the more irritating examples of arcane scientific precision, one is not supposed to say "degrees kelvin." One should instead speak of plain "kelvins." Even though something can be heated until it increases in temperature by one degree Celsius, one must say that it increased in temperature by one kelvin. I used to think that this rule came about because typewriters couldn't do superscripting, and so scientists embraced writing "1 K" instead of "1 °C." (There's a small matter of the scales being offset, too, but let's not go there right now. The gradations are the same.)

As it happens, my rather clever typographical hypothesis was wrong. The explanation is lexical.

The old name for the Celsius scale -- the Centigrade scale -- caused confusion among some Europeans. Swedish, German, Italian, and Spanish all have a word like "grade" which means "degree." Scientists thinking of relatively recent additions to their vocabulary like "centimeter" thought "centigrade" sounded like it might mean 1/100th of one degree, instead of 100 degrees. In the spirit of international cooperation sweeping the globe shortly after World War II, it was agreed that the sensible thing would be to rename the temperature scale after its inventor, Anders Celsius.

<musing>

Old Anders probably should have thought of this in the first place, being from Sweden himself, but he was evidently a humble sort. Also, he was prone to thinking in Latin, where centi- means "hundred" and gradus means "step." He is, however, to be praised for having the subtle foresight to choose parents whose last name began with C, which resulted in the preservation of all those °Cs.

</musing>

Not satisfied with the successful picking of one nit, scientists later argued that "degrees kelvin" introduced further ambiguity, for reasons passing my understanding. As I was not consulted, being busy with second grade at the time, they banished the D-word. They also agreed that while the abbreviation would be an unadorned capital K, the unit's name when spelled out should appear in all lowercase letters. I was not asked about this, either, so my new hero is the inventor of search and replace.

The whole sordid mess is described here.

What's that?

You say you like Fahrenheit better?

Sit down and be quiet, or I'll go on for fifty more pages about the superiority of SI units, the backwardness of the U.S. in failing to embrace the metric system in general, how this ties into . . . convinced? Good.

We're still wondering what kelvins might have to do with CFLs, though. What does it mean to say a bulb is "2700K" or "5000K?" I mean, the surface temperature of the sun is somewhere near 5000 °K ... sorry ... 5000 K. What might this have to do with CFLs being pitched as running cooler?

If you've peeked at this rather nice page, put up by the local government in Ft. Collins, CO, you already know.

One of the big complaints about fluorescent bulbs in the past was that they were less "warm" than incandescent bulbs. People felt that incandescents were more suggestive of candles and campfires, while fluorescent bulbs gave off light that was "cold" and harsh.

When the technology for CFLs improved, and the marketing ramped up, the suits naturally insisted that their bulbs be packaged with "warm" printed all over the box. Surprisingly, a convention has arisen to lend some precision to the perception of light emitted. This convention is called "Correlated Color Temperature," or more commonly, just "color temperature."

If we return once again to high school, physics class this time, we recall that when things are heated, they give off light. As they get hotter, the color of the light changes. Think of heating a piece of iron: first it glows red, then it turns yellow, and finally it gets blindingly white.

Thus, one can associate a characteristic temperature with the "feel" of the light, as the city fathers of Ft. Collins tabulate. 1500 K corresponds to candlelight. 2700 K, it turns out, corresponds to standard incandescent bulbs. And 5000 K harshes your mellow -- it corresponds to sunlight at midday.

Nice, huh? At least one of my guesses turned up in the right ballpark.

But hold on a minute.

Conventions are great and all, and it's a bonus that for once, there's some solid science behind the ad-speak. But an increase in temperature (more Ks) means things are getting hotter. So why is a relatively cool color called "warm light," and a hotter color called "cold?"

This makes me a little crazy, as I'm sure it does most scientists, and I'm now suspicious that they insisted on "kelvins" as revenge for these nonsensical colloquialisms.