Compact Fluorescents: The Choice Of A New Generation

compact fluorescent lamps should be on every Green Lights participant's most wanted list. The practical and aesthetic features of today's high-quality, energy-efficient compact fluorescents have created strong demand. When labor, energy, and materials are factored, compact fluorescents can save 65 to 75 percent in lighting costs. Compared with incandescent lamps, they generate three to four times more lumens per watt and have a rated lamp life 10 times longer—one of the more lucrative Green Lights investments.

compact fluorescent lamps come in a variety of shapes, sizes, and wattages, making incandescent retrofits easier than ever before. Their excellent color rendering index of 80 or higher nearly duplicates that of incandescent lamps.

compact fluorescent Applications

Retrofit compact fluorescent lamps are offered as modular units (replaceable lamps with a screwbase adaptor and ballast), or integral units (fluorescent lamps with a screwbase adaptor, ballast, and lamp all in one unit). With modular units, you can replace lamps three to four times without changing ballasts. Both are available with magnetic or electronic ballasts. The following applications offer a variety of features.

Twin-tube compact fluorescents —the most common application, twin tubes can retrofit exit signs, ceiling fixtures, and sconces because of their tall, slender form. But their length creates some limitations. For example, when retrofitted base-up in a recessed downlight, they can appear unsightly and create glare.

Quad-tube and triple-twin-tube compact fluorescents —designed to reduce lamp length while maintaining lumen output, the triple-twin-tube and triple-U-tube are the most compact fluorescent lamps—quadruple-twin-tubes are expected soon. These lamps suit downlights and track lights with reflectors, as well as pendant fixtures and table lamps.

Circline and square compact fluorescents —designed for table lamp applications, circline and square-shaped compact fluorescents also suit low-profile sconces and shallow ceiling fixtures; square compact fluorescents provide better color rendering.

Reflector units—these provide a wide flood beam for uniform illumination, but compact fluorescents are still a linear light source, making optic control a challenge. These lamps work best in recessed downlights in ceilings less than 15 feet high and in track lights when tight beam control is not needed.

Retrofit Considerations

Although compact fluorescent retrofits are great successes, they do raise application issues. For example, not all incandescent fixtures can handle other lamps. The following issues should be considered before upgrading:

Size

Shape and size vary, so certain compact fluorescents work better in certain applications. Check manufacturer data for lamp/adaptor dimensions to ensure proper fitting.

Dimmability

Current screwbase (retrofit) compact fluorescents cannot be dimmed— dimmer s must be replaced with switches to upgrade properly. Failure to do so is a fire hazard. Dimmable compact fluorescent systems exist, but they usually require a new luminaire, including a dimmable ballast, four-pin compact fluorescent lamp, and dedicated dimming control.

Optical Efficiency And Projection Distance

fluorescents do not provide the same optic control as incandescent or high intensity discharge lamps. Compact fluorescents with integral reflectors do not achieve the same projection distance as most incandescent lamps. Use compact halogen reflector lamps for applications requiring greater projection.

Orientation And Temperature Effects

When positioned base-up or horizontal and ambient temperature is approximately 25° C (77° F), compact fluorescents provide optimal lumen output. Enclosing compact fluorescent lamps in indoor fixtures may lower lumen output because of higher ambient temperatures inside the fixtures. When ambient temperature drops in cold regions, outdoor compact fluorescents have lower lumen output and might fail to start. Consult the manufacturer for minimum starting temperature and performance data.

Harmonic Distortion

In a typical 4-wire, 3-phase power distribution system, harmonic distortion adds current to the neutral wire. Although electronic ballasts have a higher effect on harmonic distribution, "low-harmonic" ballasts are available. When compact fluorescents are a small part of the electrical load, the harmonic current is diluted. But when compact fluorescents are a lar GE par t, specify low-harmonic electronic ballasts with less than 30 percent total harmonic distortion.

Theft Resistance

Some lamps are now designed with a locking base option. Unless a special tool is used, the lock prevents the lamp from being removed from its socket. This not only prevents theft, it is ideal for preventing "snapback," the tendency for occupants to replace expired compact fluorescents with incandescents.