Hey Mr. Green,
In the past few years we've been encouraged to replace incandescent lamps with fluorescents. It makes sense, because the fluorescent takes only 25 percent as much as energy to operate. But an incandescent bulb is relatively simple in that a thin tungsten wire is its light source, whereas a fluorescent lamp is far more complex requiring a very high voltage starter and a complex, coated tube. The extra materials needed (including mercury) never seem to be mentioned in bulb comparisons that discuss only fluorescent wattage. So I wonder whether fluorescent bulbs are really as energy-efficient as they seem.
–Bob in Tustin, California
Inquisitive folks like you have begun wondering about the total environmental impact of a given product, including the hidden costs. These questions can be very complicated and difficult to answer. In the bulb world, the answers are harder to find than usual because of manufacturers' reluctance to share information with us media dimwits.
But some life-cycle-analysis researchers have managed get a good look at the energy impacts of making bulbs. Fluorescents do require more energy to make, but still come out way ahead in net energy savings; only about 7 percent of the total energy used by a fluorescent over its life is consumed in manufacturing and other processes. Less than 1 percent of this is needed to make incandescents. But since, as you point out, fluorescents use only 25 percent as much energy to operate, so they still come out much more efficient even when you add in that extra 7 percent.
Regarding mercury, it's the source of a lot of confusion and controversy about fluorescent lights. You do need to recycle your fluorescent lamps when they perish because they do contain a small amount of mercury. Granted, even if all household bulbs were fluorescent and all of them ended up getting smashed, the net emissions would still amount to only about 6 percent of the mercury emitted by coal-burning power plants. That said, however, no amount of mercury is safe. For a comprehensive look at how to recycle fluorescent lightbulbs, go to lamprecycle.org.