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Dim and Dimmer

CFLs are great! Dimmers are great! Together? Not always.

Compact fluorescent light bulbs, better known as CFLs, are all the rage. And why not? ENERGY STAR qualified CFLs:

CFLs use at least 2/3 less energy than standard incandescent bulbs to provide the same amount of light, and last up to 10 times longer.

  • Use at least 2/3 less energy than standard incandescent bulbs to provide the same amount of light, and last up to 10 times longer.
  • Save $30 or more in energy costs over each bulb's lifetime
  • Generate 70 percent less heat, so they're safer to operate and can cut energy costs associated with home cooling.
  • Come in different sizes and shapes to fit in almost any fixture, indoors and outdoors.

Today's ENERGY STAR qualified CFLs turn on instantly, produce no sound, and are available within a warm color range, as well as cooler color tones.

To figure out how much you can save, check out PATH's CFL Savings Calculator.

A light that is dimmed by 25 percent uses about 20 percent less electricity and the bulb’s life is increased fourfold Dimmers: A Bright Idea

Dimmer switches are great energy-efficient options compared to traditional flip switches. That 's why dimmers are a key part of PATH-profiled energy-efficient lighting controls.

While some may only think of dimmers for mood lighting, the switches allow one fixture to serve several lighting functions, such as task lighting when at full illumination and decorative or safety lighting at lower settings. Furthermore, dimming increases lamp life and saves energy because less electrical wattage is used. For example, a light that is dimmed by 25 percent uses about 20 percent less electricity and the bulb's life is increased fourfold.

CFLs and Dimmers?

So what about CFLs on dimmers? Wouldn't they be the dream combination of lighting functionality and energy efficiency? Unfortunately, in many cases, the answer is no.

Dimmers work by breaking up the amount of electricity reaching the light fixture. Though invisible to the human eye, the staggered electrical current is actually making the light flicker. This is fine for an incandescent (traditional) bulb, as it simply reduces the amount of heat produced by the filament.

CFLs, however, do not use heat to produce light. Instead, a fluorescent bulb contains a gas that produces invisible ultraviolet light when excited by electricity. The light hits the white coating inside the fluorescent bulb and the coating changes it into light you can see. In this process, CFLs regulate power through the tube, which is not compatible with the dimmer's intervals of electricity interruption. So when working with a standard CFL, a dimmer would cause the CFL to dim, and eventually go out altogether. It shortens the CFL's life and, in rare cases, a dimmer operating a CFL could result in fire.

A handful of specially made CFLs, more expensive than regular CFLs of course, can be used with dimmers.Compromise and Work-Around

Fortunately, technology is bringing this pair of energy-efficient products together. About forty ENERGY STAR qualified CFLs are specially designed to work with dimmers and say so on the label. These are more expensive than regular CFLs, but reap all the regular energy saving benefits.

Besides price, dimmable CFLs have some other shortcomings: 1) they only dim to about 20 percent of the rated lumens and when turned down farther they turn off completely, and 2) as incandescents get dimmer the light gets softer -- more romantic you might say -- but dimming CFLs don't share that characteristic.

Be careful about using CFLs in tandem with photocells -- those light-sensitive switches that automatically turn lights on at dusk. CFLs and photocells sometimes have the same incompatibility problems as CFLs and dimmer switches. The solution: Either ask for a compatible timer (most but not all timers are compatible with CFLs) or buy a dimmable CFL to use with your photocell.

Nostalgic for the days when a light bulb was just a light bulb? Take heart. While lighting our homes has become more complex, the technologies available to us offer impressive returns in energy savings and light quality. So it's worth the time to evaluate your lighting needs room by room, using CFLs wherever practical.

In all cases, check the package details of your CFL bulbs and your dimmer to ensure that they are compatible. Only then can these energy savers come together in your home.

Content updated on 5/24/2007

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