Compact Fluorescent Lights (CFLs)

Are They Worth the Switch?

By Kenneth Barbalace

[Apr. 18, 2007]

When someone says "fluorescent light," what is the first thing that comes to mind? Maybe you are reminded of a bad hum, an irritating flicker, and cold greenish light. Anyone who has worked in an office environment has been subjected to the irritating flicker of a failing ballast. So when we see and/or hear advice and/or advertisements suggesting we switch out our incandescent bulbs for compact fluorescent lights (CFLs) we are conflicted. We'd love to save money on our electric bill and be environmentally responsible, but CFLs seem to be very expensive, and we don't want to be subjected to bad "office" lighting at home.

As I am particularly sensitive to flickering lights, I was very reluctant to try CFLs. Just over a month ago, however, the 150-watt bulb in our torchiere lamp burned out and needed to be replaced, so I decided to give CFLs a try (don't knock something until you try it). At the same time I bought a 3-way torchiere lamp that had a translucent bowl. This lamp would replace our current torchiere lamp that had an opaque reflector bowl to direct all light towards the ceiling and used a dimmer switch (most CFLs can't be used on dimmer switches). Because of the translucent bowl, the new lamp allowed the light to diffuse downward to where we needed it most, thus more effectively lighting the room.

First and maybe the most important concern for you might be the overall performance of the CFL. The quantity of light produced is equivalent to the incandescent bulb it replaces; and since we replaced the lamp at the same time, the room is more effectively lit. The bulb does take about a minute to warm up during which time the light isn't at full strength. Because I bought a soft-weight CFL the light is slightly yellow. To avoid the yellow light, I'd recommend buying a "bright white" or "daylight" CFL. I have since purchased a daylight CFL for our bathroom; and, indeed, the bathroom looks like it is being lit by natural light. There is no hum and no flicker. So, provided I can buy bright white or daylight CFLs, I am sold on buying CFLs instead of incandescent bulbs, at least until LEDs become commercially available at cost effective prices.

As I do work at home, the lamp in question is our most used light. Since the room receives very little natural light, the light is used about seven hours a day. For the same amount of light as a 150-watt incandescent bulb, the new compact fluorescent light consumes only 32 watts. This means that the new CFL is saving about 826 watts of electricity per day. At $0.15 per kw, this represents a savings of around $4 per month. This may not sound like much, but it will only take two months for the new bulb to pay for itself in savings; and over a course of a year it will save us around $45 per year. Just think, changing one bulb in the most used lamp in our home will save us enough money in one year to pay for both the bulb and an inexpensive yet attractive lamp.

So, how does this bulb do for reducing our carbon footprint? Assuming that the average coal or oil fired power plant releases around 1kg of CO2 per kilowatt(1), this bulb could reduce our CO2 emissions by around 300 kg (660lbs) per year. Over the rated life of the CFL, which is 10,000 hours, it could reduce our CO2 production by around 1180 kg (2,600 lbs) and save us around $177 as our electric rate is just over $0.15/kw(2). The bulb will save us even more money when we switch over to a "green" energy supplier (produces electricity from all renewable sources), a choice that would increase our electric rate by 1/3. Even though our 3-way CFL costs $9.97(3), over its life we will see an additional savings of about $23 from not buying the eight 1,200 hour incandescent bulbs necessary for the same 10,000 hours of service life (assuming that 3-way bulbs cost around $3-$4 each).

There is one drawback to CFLs, and that is, like most fluorescent lights, they contain mercury and thus should not be disposed of in the garbage once they burn out. Instead, they need to be retained unbroken and disposed of via state and/or local laws, which may require taking them to a local household hazardous waste facility, waste transfer facility, recycler, or store where they were first purchased.

Because of the mercury issue, compact fluorescent lights are not without their problems. However, they are a very good interim step until a more promising technology like LED based incandescent replacements become commonly available to the consumer. If you want to cut your electric bill and your carbon footprint, seriously consider replacing out your incandescent bulbs with CFLs, starting with your most used lights. You may really appreciate the change when you get your next electric bill.

Incandescent vs. Compact Fluorescent Lights

IBCFLEnergy Saved w/CFL (a)CO2 Saved (b)Money Saved w/CFL (c)CFL Cost (3)IB Cost/Life (3)Cost Savings w/CFL (d)Total Potential Savings w/CFL
(a) Energy saved based on CFL 10,000 hr rated life.
(b) CO2 Saved based on electricity produced by coal or oil fired powerplants (1kg CO2 per KW generated).(1)
(c) Savings based on $0.15 per kw over life of CFL.(2)
(d) Savings based the replacement cost of incadescent bulbs vs. CFL.
40W9W310kw310kg$47$4.97$1.19/1500hr$2.96$49.96
60W14W420kw420kg$63$4.97$1.74/1500hr$6.63$69.63
75W19W560kw560kg$84$6.97$1.74/1500hr$4.63$88.63
100W23W770kw770kg$116$6.97$1.74/1500hr$4.63$120.63
150W42W1180kw1180kg$177$6.97$2.78/750hr$30.10$207.10

Energy Savings Calculator

Use this JavaScript calculator to estimate how much you could save by replacing some or all of the incandescent bulbs with compact fluorescent lights.

Num of BulbsWattage of Replaced BulbsHrs/Day Used Approx. Savings Per Year Approx. Annual CO2 Reduction(1)
1) 
2) 
3) 
4) 
Totals: 

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Bibliography

  1. Stefan Rahmstorf University of Kiel Germany; Ecofarm; NewScientist.com; 2/3/1996; (last accessed 4/15/2007) http://www.newscientist.com/backpage.ns?id=lw214
  2. Standard delivery and supply rates for Central Maine Power as of April 2007
  3. Price check of Home Depot in Portland Maine on April 15, 2007
  4. Compact Fluorescent Light Bulb (CFL) FAQs; GE Lighting, General Electric Company; 1997-2007; (last accessed 4/16/2007) http://www.gelighting.com/na
    /home_lighting/ask_us/faq_compact.htm

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