Light Bulb Side Note (then back to heating systems)

Now when you are intending to make light with electricity, instead of heat, your efficiency number is going to shift. Standard incandescent light bulbs have been creating light for us since Thomas Edison (or before if you credit those that did not file a patent). These bulbs create light from electricity by heating a wire up just like your toaster does; only they hold a different type of metal that intends to focus on the visible light spectrum instead of infrared.


While techs have created better filaments for light bulbs that last longer, and are slightly more efficient, we are still operating around 10%. Meaning that of the total amount of electricity that enters the bulb only 10% of it becomes visible light. The other 90% is emitted as heat. I am sure this does not come as a surprise as it is very easy to burn your hand when trying to switch out an incandescent bulb that had been on for a while.

(As a side note, the visible light is going to bounce around the room being absorbed by the surfaces until it is gone. When absorbed, i.e. stopped, that light will create a small amount of heat. So, one could say that a light bulb is 100% efficient at creating heat, because at the end of the day every watt of electricity that enters the bulb eventually becomes heat.)


While the efficiency of incandescents may get slightly better over the next few years it is highly unlikely that they will get anywhere near the efficiency of a compact fluorescent lamp (CFL). A CFL, just as a standard fluorescent, creates a ultraviolet light stream thru the center of the tube. I had the chance to see one a few weeks ago at a light show, and it looks exactly like a Star Wars light saber.


Generally speaking we do not see this portion of the light as it is hidden behind the white phosphor coating on the inside of the glass surface. As the ultraviolet light strikes the phosphors it excites them and they emit visible light. As a team these two create light 75% more efficiently than an incandescent, since less electricity is released as heat.

(Again, the light will bounce around the room until it becomes heat as well, but if you ever try to remove a CFL that has been on for a while you will find that they do not create nearly as much heat.)

And since the goal is to create visible light, these are a clear winner. Add to that that they have a lifespan 10x the lifespan of an incandescent and the fact that they cost more upfront is no longer an issue.

A CFL Detour to Conservation 101

Last week we passed out 19,500 CFL bulbs to our customers here in McMinnville, as a part of our conservation effort. Since then the local news paper has published two articles about CFLs with a strongly negative slant. Attached is my responce to the editor. I may also be using this to buy myself a little more time to finish the Energy 101 post:

http://www.newsregister.com/news/story.cfm?story_no=238072

http://www.newsregister.com/news/story.cfm?story_no=237176

Dear Editor,

CFLs are not a perfect light source.

As has been covered twice in the last week by your paper, they contain mercury. Mercury is an essential part of CFLs and a bulb typically contains between 1.4 and 5 milligrams.

In order to provide some context to this number: older thermometers typically contain 500 milligrams of mercury, and mechanical thermostats typically contain 1,000-3,000 mg of mercury (some of these were still available for purchase as late as December 2003).

The EPA estimates that the U.S. is responsible for the release of 104 metric tons of mercury each year. Most of these emissions come from coal-fired electrical power, and in a national energy market any hydro power we do not use in the NW can be sold to offset coal power elsewhere.

So when we say that CFLs use 75% less electricity than an incandescent, we are saying that 75% less mercury is released into the atmosphere when you use one instead of an incandescent; to the tune of 4.5 mg of mercury over the life of the CFL. Because the mercury vapor inside fluorescent light bulbs becomes bound to the inside of the light bulb as it is used, there is an average of 0.4 mg of mercury free in the bulb at the end of its life. This gives us a net total of 4.1 mg of mercury saved from the environment even in the worst case scenario where the bulb ends up in the landfill.

If all 290 million CFLs sold in 2007 were landfilled, they would add 0.1 percent to the U.S. mercury emission caused by humans. So harping on the mercury in CFLs is akin to complaining about a dripping sink when a fire hydrant is open in your front yard.

CFLs are a better environmental choice than incandescents.


Matt Deppe
B.A. Philosophy
McMinnville, OR

P.S. If a CFL falls in the forest and breaks, and no one is there to lick it, is anyone really hurt?

I ran out of room in the letter to discuss the Energy Independence and Security Act of 2007, which mandates incandescents to be 25% more efficient then they are now by 2012 or so(mentions nothing about anything being illegal), and also has a list of exceptions longer than my arm that covers all specialty bulbs etc. I also have yet to find a legitimate and verifiable source that states that a broken CFL pose a serious health concern to anyone assuming they are not going to eat it.