$50 Lightbulbs?

This is actually something I meant to post much, much earlier but only got to doing now.

Wesley J. Smith, as part of his coverage of environmental news he calls "Global Warming Hysteria" recently discussed a $ 50 LED light bulb. I commented on the article, saying that he didn't mention that CFLs were much cheaper than the one he described and that that the improved energy efficiency made up for much of the cost. The article and some of the comments made me want to see for myself how much savings CFL bulbs represent.

Sources for Starting Numbers

From an October 2010 Consumer Reports article*, I discovered a 60-watt incandescent bulb is equivalent to a 16-watt CFL or 12-watt LED. Incadescents have an average life expectancy of 1,000 hours and CFL's 8,000.

From the Department of Energy's statistics, I found the average cost per kilowatt hour is 9.62 cents.

By skimming various online sites, I chose 60 cents as a reasonable average cost for an incandescent and 5 dollars for the CFL.

I estimated that an average bulb is probably lit for about 5 hours daily. I didn't try to find specific statistics because a) this affects all the bulbs equally and b) it would probably be difficult to find.

Results

From this data,  I determined the average cost to power a single incandescent bulb to be $11.62 over a year, compared with $ 3.94 for a CFL.

For the sake of argument, I also compared the best-case scenario for incandescents with the worst-case for fluorescent bulbs. To do this, I basically cherry-picked the numbers most favorable to incandescents and those least favorable to CFLs. Even still, the CFLs won, $ 5.90 beating out $ 9.63.

People interested in looking at my math can examine the spreadsheet I used, complete with the formulas. You will note I ran the numbers for LEDs, but since I was less confident of the numbers I plugged in, I didn't put the results in this post.

Cross-checking

How accurate was my estimate? I found three other cost comparisons. The first is a U.S. News and World Report article.  It claims changing 30 fixtures results in savings of $ 440 to 1,500 over 5 years. I show an $ 8.05 savings over one year for one bulb. Multiplying that by 150 gives $1207.50, meaning my result was perhaps a bit on the high end.

Next, I found GE Lighting's savings calculator. It too suggested my estimate was high: it gave a one-year savings of $ 5.91.

According to Energystar.gov, CFLs save $ 40 over the bulb's lifetime. If they last five years, that puts savings at $ 8, close to my estimate.

From all this, I think we can be reasonably confident fluorescents save money.

More Information

As it happens, both Factcheck.org and Politifact looked at closely related claims. Factcheck responded to the question: "Will energy efficient light bulbs cost $ 50 each next year?" with the following:

Some light emitting diode bulbs may cost that much, but some halogen incandescent bulbs and compact fluorescent bulbs go for about $1.50 to $3 each.

Politifact did a slew of articles on the subject. Here they are:

• Whether or not fluorescents are safe & environmentally friendly
• On the cost of non-incandescent bulbs—alegedly six times more expensive
• What exactly the government is mandating.
• And more...

 *Full, official citation:

Lightbulbs. (2010). Consumer Reports, 75(10), 26.

First Two Reviews

As I mentioned before, I have several reviews to share with you. I actually read and reviewed these a while ago, but only just got around to polishing them.

A Short Course in Intellectual Self-Defense
Normand Baillargeon takes the whole "self-defense" metaphor pretty seriously. Take this for example: "Your brain is territory that an enemy wants to occupy by persuading you of certain things." The writing has a tendency to go to such extremes occasionally, but it is a very good book.

In particular, his chapter "Thirty-one Strategies for Fostering a Critical Approach to the Media," near the end has an excellent list of tips. They are very practical, which is something I like in books on this subject. They are rather involved--one suggests reading the past fifty articles by a given author when analyzing a given op-ed.

Another bias that shows through clearly is his love of Noam Chomsky: the front cover even says "release your inner Chomsky." He quotes Chomsky once or twice within, but generally it doesn't seem to unbalance the work unduly. The exception is in the aforementioned chapter of 31 strategies which includes, as number 25, "Read Chomsky." A list of recommended authors wouldn't have been remiss, but giving Chomsky his own point? A bit much.

I don't know very much of Chomsky; indeed, what I do know mostly comes from cursory research after reading this very book and some unrelated research I did on his work on mass media*. Since he seems an advocate of critical thinking, I suppose his inclusion is somewhat appropriate. I still think it's a bit extreme—perhaps the book ought to have been titled "A Chomskean Approach to Critical Thinking."

Anyway, don't let the author's politics dissuade you from reading this useful text. It is a practical introduction to critical thinking and recommended to any student of critical thinking.


The Demon Haunted World: Science as a Candle in the Dark
This book is more of a case for science and against psuedoscience, rather than a "how-to" book on critical thinking. Nonetheless, it has excellent parts and can be read as a manifesto in favor of rigorous checking of claims. Carl Sagan is an engaging writer and comes across as very human and sincere, important in a book on a subject that could easily be cold and dull.

This book does belabor points. Lee Dambert, in his Los Angles Times review, writes that eight chapters of UFOs "seems a bit excessive."Since the points are made well and illustrated with copious examples the book is saved from becoming a rant; Dambert himself considers this issue "a minor quibble."

Some people have found this book to be anti-religion or partisan. The book ends with two chapters Sagan wrote with a co-author that deal with politics. However, the main thrust of the book is basically non-political and as a whole can't be described as partisan. (Sagan himself considered the last two chapters non-critical.) The anti-religion claim is a bit harder to shake. Certain religious practices and beliefs would easily fall under Sagan's definition of "baloney." Examples would include faith healing, astrology, and probably miracles in general.

While Sagan was an agnostic, it's harder to make a case that this book is an attack on religion generally. He doesn't group religious belief explicitly with belief in psuedoscience or try to replace it with science. Certainly the skepticism he discusses in The Demon Haunted World is popular among atheists, but certainly critical thinking is compatible with religious faith, even if "skepticism" is.

Probably the closest he gets to condemning religion is the chapter "The Dragon in my Garage." Sagan informs us that he has a bona fide dragon in his garage. However, he tells us that the dragon has the power of invisibility and so we'll just have to take his word for it. He argues that such is the nature of many allegedly true supernatural phenomena: any non-appearance of the supposed effect is explained away, so it can never be disproved. This is a similar to popular lines of reasoning employed against the existence of a god, and so it could be taken as a justification of agnosticism. That may be the case, but I think Sagan was more concerned with psuedoscience than religion and I think most religious readers will get plenty out of it anyway.

One of the best-known parts is the baloney detection kit. (In fact, Normand Baillargeon includes a summary of it in his book.) Even if you find the main text tedious, before returning it (or selling it) skip to chapter 12, where the kit is. It consists of nine warning signs that something is, well, baloney.

So there you have it: two good starting texts on critical thinking. Look for more in the coming weeks: I just finished two books and am writing up reviews now.

* Specifically, his work with Edward Herman on "Manufacturing Consent." In it, they lay out a theory of mass media called the Propaganda Model.