A Little Light Reading

I guess it should have been a red flag for me when my co-worker replaced some light bulbs in January and asked me if I knew how to dispose of them. I looked up online how to dispose of CFL’s. Hmmm…if you have to take something to the Sedgwick County Household Hazardous Waste Facility – and they will only accept it if it is unbroken – you might have a hazardous product. At the time, that did not cross my mind.

A few weeks ago a client came into my workplace, looked up at the CFL’s above me and commented, "You know, those are bad for the environment. They have mercury in them." I smiled and replied, "Oh, really?" I thought the man must be mistaken. I had heard that compact fluorescent lights are supposed to be a better environmental choice than regular incandescent bulbs. I realized I didn’t really know much about incandescent bulbs, CFL’s or LED lamps, so I decided to enlighten myself on the subject.

I read a post on the LED Source webpage entitled Bye Bye 75W Incandescent Light Bulb – Phase-out Continues. The post describes how some incandescent bulbs are being phased out due to their inefficiency. The technology of these bulbs has changed minimally over time. It is surprising that they convert only 10% of the input energy into light and the rest is dissipated as heat. The Energy Independence and Security Act of 2007 requires light bulbs to be 25% more efficient. Thus, traditional 100W, 75W, 60W, and 40W bulbs are gradually being phased out because they cannot meet this target.

According to the EPA, the mercury contained in CFL’s is not a significant environmental hazard. Because CFL’s require less electricity, less coal would have to be burned at a power plant. Since the process of burning coal releases mercury, if we burn less coal to generate electricity, we also release less mercury into the environment.

My conclusion is that CFL’s really are better for the environment than incandescent bulbs because they use significantly less electricity. Last fall my mom asked me to help her replace a couple of incandescent bulbs with LED lamps at my parents’ winter cabin. She was eager to do the replacement because the LED’s would require much less electricity. I was so concerned about which wire I had to connect to which other wire that I didn’t think to ask how much less electricity the LED lamps would save. The U.S Department of Energy gives a comparison on their site. The information below is an excerpt from their table. While the table shows the life of an LED lamp to be 25,000 hours, other sources list it as high as 50,000 hours. The annual energy cost in the table is based on having the light on 2 hours per day and the cost of electricity being $0.11/kwh.

Comparisons between Traditional Incandescent and Energy-Efficient Lightbulbs


60W Traditional Incandescent

Energy-Saving Incandescent



Energy $ Saved (%)




Annual Energy Cost*





Bulb Life

1000 hours

1000 to 3000 hours

10,000 hours

25,000 hours


What’s the catch? Why have we not all switched to LED lamps? The initial cost of an LED lamp is higher than for an incandescent bulb or a CFL; however, over time the difference is made up by the efficiency and the lifespan of the lamp. I am looking forward to the next time I see the client who informed me that CFL’s are harmful to the environment – I can’t wait to tell him what I have learned. That will be right after I inform my boss that we really ought to replace our office CFL’s with LED’s – to save money and the environment.

To see detailed comparisons of cost and other features of incandescents, CFL’s, and LED’s check out the Eartheasy website.