Ballasts
All FL and CFL lamps require a “ballast” that converts the supply current to high-frequency AC, exciting the lamp. Early ballasts were magnetic and used an inductor for this conversion, which was inefficient, noisy, and caused irritating flicker of the lamp. Modern electronic ballasts that solve these problems are being rapidly phased in by manufacturers.
With most FL lighting, the ballast is inside the fixture and the lamp simply attaches with pins on each end. Both FL ballasts and lamps can be replaced. Most residential CFL lamps use regular Edison screw bases with the ballast contained within the lamp; these ballasts cannot be replaced. Other CFL ballast types are available, though. “Pin-base” CFLs contain the ballast in the fixture, with the lamp connecting via two or four pins. There are a variety of different pin bases, so consumers need to be sure and get the correct lamp for their ballast. The new GU24 pin base is made to comply with new Energy Star fixture standards, but the lamp, not the fixture, contains the ballast. The new base simply prevents users from installing inefficient incandescent and halogen lamps into a new Energy Star-rated fixture.
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| To work well with modern lighting technologies and to save energy, modern solid-state dimmers are a must. |
Dimmers
Dimmer switches have long been an effective way to adjust a room’s light levels, but problems with dimming new, efficient lighting technologies have become a major complaint. Older dimmer switches simply used a rheostat to lower the voltage sent to incandescent or halogen lamps. The surplus energy was converted to heat inside the dimmer switch, resulting in dimmer lighting with no energy savings.
Modern dimmer switches use semiconductor triacs to chop up the AC waveform and reduce the amount of time the lamp is actually on. This pulsing is supposed to occur faster than the eye can detect, but different people have different sensitivity to flicker. “Some lamps appear to flicker more than others due to light modulation,” says Mark Rea, director of the Lighting Research Center at Rensselaer Polytechnic Institute. “However, all lamps flicker at the same rate.”
Triac dimmers can also cause an audible buzz within some lamps; more expensive dimmers use more electronics to reduce this effect. Note that CFLs advertised as “dimmable” can only be dimmed by about 20%, after which they will simply shut off. Three-way switches are another form of dimmer and require special three-way CFL lamps.
On Rea’s advice, I recently took a research trip to my local big-box store to check out my dimmable options. One major-brand CFL package said “dimmable” in large letters, with the fine print below reading “Works with most dimming switches.” “Most” was not very helpful, so I asked store personnel—no luck there, either. It finally took a call to the lamp manufacturer to get a list of dimmers that would absolutely, positively work with that particular lamp.
“The industry does a disservice to itself and consumers by not quantifying and bundling the information consumers need to purchase lighting,” Rea says. “There are easily 20 benefit factors that affect whether they will be satisfied with their purchase, but it would take too much time for the consumer to research them all.”
That certainly echoes my experiences in efficient lighting over the last two decades. And until the lighting industry does get its consumer education act together, my advice is that when buying lamps, fixtures or dimmers...always save the receipts!
