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January 05, 2007


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Just out of curiosity, does anyone know if CFLs are unambiguously better for the environment? Environmentalists don't always make good cost-benefit calculations about things like nuclear power, organic foods, etc. So I guess I'd want to know, are CFL bulbs more expensive to make? Do they last as long? Are their materials more or less toxic?


Oh, I guess I meant, "Assuming the Peltzman effect doesn't overwhelm their energy efficiency, are CFLs unambiguously better for the environment?" Actually, I'm not sure the Peltzman effect is worrisome here. If we can get brighter light for the same energy cost, that seems like a worthwhile improvement (barring light pollution concerns, which mostly concern outdoor lighting I think). The problem would be if we actually used MORE energy when we switched to CFLs (which I suppose would happen if the substitution effect outweighed the "income" effect).


The power savings are so great that any Pelzman effect will be overwhelmed; you'll find you can get brighter light while still using less power with a CFL. A 22 watt CFL has about the same light output as a 100 watt incandescent--so you'd still be getting a huge power savings AND double the light. Or triple it.

James Wasserman

You have really confused a number of issues.

It is true that the of power consumption has been watts!

WATT - The unit of electrical power used to rate the rate in which the lamp consumes energy.

The measure of light output from a source is called Lumen (luminous flux).

Examples: A dinner candle will produce about 12 lumens. A 60 watt incandescent lamp about 840 lumens.

Then to confuse the issue you have to know about Lux or the measure of the amount of light falling on a surface as not all of the lumens reach a surface to light. One lux is equal to one lumen per square meter. Ten lux equals one foot candle.

Now that you are confused by the definitions it should be noted that all manufacturers of fluorescent lamps produce product which delivery differnt amounts of lumens based on their product and process, and that they may have differnt Color Renderings - the measure of comparison to "daylight" and Color Temperature (K), the amount of yellowness to blueness....

Most CFL's produce slightly more lumens for their equivalent replacment of indcandescent bulbs.

CFL's will reduce the amount of power by 2/3 to produce the increased amount of lumens, usually 10% - 15%.

CFL's produced today have a useful life of 8,000 to 10,000 hours.

With the costs of CFL's coming down, and the energy savings at 2/3, they are a much better investment savings the consumer lots of money over the useful life.

Randy Picker

James (Wasserman):

I don't think that I am understanding your point. The issue isn't whether CFLs will be a better deal for consumers. Clearly, if they produce the same quality and quantity of light as ordinary bulbs for less power, it may make sense for the consumer to spend more upfront for the CFL.

My point is about the environmental claims of reduced energy use. That depends on the assumption that consumers don't choose to upgrade their light quality as they move from ordinary bulbs to CFLs. I claim that many will do just that, as many of us can't put higher lumen bulbs into our current lamps. We have already maxed them out.

Switching to CFLs means we won't make the 60 watt ordinary/15 watt CFL swap that the environmental groups are using in calculating their projections. Instead, we will swap that 60 watt ordinary for a 22 watt CFL or perhaps even something much higher, and that will eat into the projected carbon dioxide savings.

Yes? No?


Mr. Picker, I agree that the Peltzman Effect is likely to play a small role here, but I think it's a reach to think that it will be as large as 100%. That assumes that consumers have no interest in saving money. I think that we can safely assume that consumers are cost-conscious and will attempt to save money where possible. The Peltzman effect cannot be used to turn economic logic on its head; it applies in cases where the standards of evaluation shift. Inasmuch as lamps are fairly cheap, most people have already illuminated their homes to the desired level; the opportunity to increased the lighting level may not be important to many people. Hence, I don't expect a large Peltzman effect here.

I refer to all this as "the perception of adequacy". If the price of paper clips were to drop tenfold, would you buy ten times as many paper clips? Would you even buy twice as many paper clips? Most likely you wouldn't buy any additional paper clips, because you already perceive your supply of paper clips to be adequate to your needs.


The "max out" factor you point out, while real, does have a limit. No one wants to live in a tanning salon. I suspect that people will find a 60 Watt CFL will be too bright for a reading light.


It is always nice when faux economic speculation is backed some measure of fact. The facts about CFL is that they are more expensive than incandescents, they last much longer than incandescents, and that they use mercury in the manufacture, thus are an environmental hazard unless disposed of properly. Further, the technology seems to be improving: bulbs I bought 18 months ago had a 3 - 5 second delay from turn on, to actual full light; today's bulbs light instantly. I suspect that a 60 watt CFL is possible but I have never seen one for sale in the stores and a google search for "60 watt CFL" yields results that point to 60 watt incadescent equivalents (13 to 15 watt CFLs).

Finally. a quick Google search on seatbelts and Peltzman (or a search of Steve Levitt's blog) --- not as effective as Westlaw or Lexis, perhaps, but sufficient for these purposes --- suggests that the Peltzman Conjecture may either be wrong, or at best, vastly overstated. Seatbelt use apparently contributes to substantial savings of lives. The seatbelt laws save lives and seem worth the cost and bother. Not that I necessarily wear them all of the time, of course.
I am convinced about CFLs, however, and pick them up (usually on sale for about $1 each, or less) when I need them. Can't say if they last 5 or 8 years, but they do seem to last longer than incadescents.


Things to watch for with these:

A. Color of the light - one off-brand we tried had light we found to be sort of sickly greenish.

B. We WILL need to pay attention to Lumens.

C. These bulbs (and all fluorescent bulbs) are a hazardous waste. Dispose of properly.

D. Do not try these in cold places. No Fluorescent bulb works well at 20 degrees.
The colder it gets below that the worse the performance is.

E. There is a warm-up period. Some lights get much brighter over the first 30 seconds (or longer).

How we are using them.
Yep - we are trading the power and $ saving for more light.

2 ways:
1. Using a brighter bulb than we had in that spot before.
2. Leaving lights on longer in certain spots because they use so little power.

BTW - While these lights last 4x longer and use 75% less power for similar brightness we also have two new LED lights in our house. These babies use 1/10th the power (90% reduction) and last 50x longer but are only available in specialty sizes at the moment.

Brian MacLeod

I remember Peltzman's seatbelt safety article also. I remember two arguments that minimized the impact of Peltzman's intelligent economic analysis. First, there are diminishing returns to risk taking. People will not eventually drive into walls on purpose just to test their airbags and the joy of the risk. Also, even if the safety measures were completely offset by the increase in risk taking, there still is a net gain in social welfare because the driver taking more risks will be operating on a higher indifference curve.

Finally on the incandescent versus fluorescent light bulb, there are two big problems with switching to fluorescent bulbs. First, fluorescent bulbs are worse for the eyesight than full spectrum incadescent bulbs, and, second, fluorescent bulbs contain mercury and, if just thrown out, will create immediate emnvironmental problems that might outweigh the environmental benefits from decreasing energy consumption and thus the CO2 emmissions from power plants.

Larry Wood

Being a technology professional for over twenty years, I've found myself in brightly lit offices filled with overhead fluorescent lighting for most of my career. Interesting to me is that I don't like it. I find the brightness clashes with computer monitors so much that it becomes difficult to work after a few hours. However, turning off the bright flourescents and using a small 40 watt incandescent lamps instead eases the strain on the eyes a great deal, at least for me. How does this affect the comparison regarding energy consumption? Perhaps energy savings needs to be less about having your cake and eating too and more about evaluating just how much light you really need. Are eight 13 watt fluorescents better then one 40 watt incandescent? You tell me.


I think this is a Moot Point Even if your going to Swap out for CFL's with Higher Lumens bulbs. A 30 watt CFL (equivalent to 125 watt incandescent.) A now let's think in terms of 60W CFL that’s equivalent to a 250w Incandescent. I've seen a 250w+ High intensity Discharge bulb (HID). I can't see anyone wanting that it there house maybe in barn or a huge garage. Looking a bulb that bright can cause permanent eye damage in about 40 seconds and were talking about your whole house. NOT LIKELY. Plus CFL's Run cool at lower Wattages By comparison to the equivalent Incandescent, but get a 60w CFL and you tell me if that’s still cool! This still does go into the Base of the bulb, most high Watt CFL use a Mogul base not standard so you would need an adapter to fit standard. Ok I'm done ranting now!

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