Dimmable Compact Fluorescent Light Bulbs: Do They Save Money?

As incandescent bulbs fall increasingly out of favor, to the point that they are being phased out by many governments (a potential development in the United States by 2014), consumers are working to educate themselves about alternative light sources. The most widely available low energy light bulb at this time is the compact fluorescent lamp or CFL. Although modern CFLs were developed in 1973 by a General Electric engineer in response to the oil crisis, by 2007 they had gained only a 20% market share in the United States.

Early CFLs were awkwardly shaped and did not fit all forms of light fixtures. The bulbs offered dim, harsh illumination and tended to have an annoying flicker. Current CFL bulbs, however, have a refined form factor that easily matches any fixture and they produce light equivalent to conventional incandescent wattage ratings in a range of tones from cool white to natural daylight. Thanks to the integration of a high frequency ballast, no visible flicker can be detected, but the bulbs do require a short warm-up period to give off their full light capacity. (Also, as a word of warning, CFLs contain mercury, which presents a chemical hazard if the bulb is broken and the units must be disposed of properly.)

Another barrier to acceptance of CFLs was the fact that they could not be used in light fixtures with dimmer switches. Dimmable compact fluorescent light bulbs are now available, but they are more expensive.

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- An eight-pack of GE 13-Watt Energy Smart CFLs with a light equivalency of 60-watts cost $12.62 or $1.57 a bulb. They have an expected operational life of five years.

- One GE 15-watt Dimmable CFL with a light equivalency of 60 watts costs $11.56. Because the unit can be dimmed to 20% of its maximum output, the bulb carries an expected operational life of six years.

Will dimmable compact fluorescent light bulbs save you money? Yes and no.

Lights on a dimmer switch save electricity on a ratio of roughly 50% of the bulb's wattage. A 100-watt light bulb turned down by half will use as much electricity as a 50-watt bulb. A CFL will add 75% more savings to the scenario. (Note that all prices and calculations are approximations based on the national average cost of electricity. Bulb prices will also vary.)

- A conventional 100-watt incandescent bulb dimmed to half capacity and burned four hours a day at an average electrical cost of .12 cents per kwh will cost $8.76 a year to operate plus $1.50 for the bulb. Total cost: $10.26

- An equivalent 23-watt dimmable CFL working under the same circumstance costs only $2 to burn for a year, but $14.53 for the bulb itself. Total cost: $16.53.

However, if you use a 60-70 watt CFL equivalent (13 watts) on a regular toggle light switch for the same period of time, you're only going to spend $2.27 over a year with the cost of the bulb at $1.57. Total cost: $3.84.

Basically the choice to buy dimmable compact fluorescent light bulbs comes down to what kind of existing fixtures you own. The primary advantage in using the bulbs in existing light dimmers comes in lowering your home's greenhouse emissions. You will save money on electricity, but that savings is eaten up by the cost of the bulb. Your real savings may lie in changing out the dimmers for regular switches and going with CFLs at a set wattage.

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2 Responses to “Dimmable Compact Fluorescent Light Bulbs: Do They Save Money?”

  1. Luciana Says:

    A dimmer switch can give a more relaxed feel to a room than the white glare of full-strength lighting. Turning down the lights also saves electricity. At the same time, compact fluorescent lights are very energy efficient. Can you get the best savings by using a dimmer switch with compact fluorescents? Or will the lights explode on you and destroy that mellow mood lighting?

  2. swapna Says:

    My brand name CFL’s have failed at a slightly greater rate then the incandescents they replaced. And no, it’s not the wiring. The “brand name” units were low performance/reliability.

    Over a 7 year period, the cost of replacement is higher than the cost of the electricity saved.

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