Halogen lamps, CFLs, MH lamps, and LEDs are all used in track lighting (Table 1). Each has strengths and weaknesses.
Table 1: Choosing the right lamp type
When choosing track lighting, it’s important to consider how you’re going to use it—each type of lamp is appropriate in different applications (A). Lamp types—halogen, CFL, metal halide, and LED—also differ in efficacy, life, and color quality (B).
Advanced halogen lamps. Advanced halogen lamps use advanced halogen infrared (IR) technology. IR coatings redirect wasted heat energy emitted by the lamp filament back to the filament to increase its temperature and thus increase light output without increasing wattage. These products provide a 20% to 30% increase in efficacy but cost two to three times more than standard halogen products.
Metal halide lamps. MH lamps, especially ceramic metal halide (CMH) units, have improved in recent years and can compete with halogen lamps in most applications except for deep dimming; MH lamps suffer from an undesirable color shift when they’re dimmed. They’re generally not dimmable below about 50% of initial output. CMH lamps offer better color quality and exhibit less color shifting than conventional quartz MH lamps, and their light output degrades more slowly. CMH lamps provide good color quality, long life, and a variety of lamp shapes and sizes—including MR16, PAR20, PAR30, PAR38, T-6 single-ended, and T-6 double-ended—all of which have been incorporated into track lighting designs. Newer CMH lamps that draw as little as 20 watts (W) have enabled the technology to compete with halogen lamps and CFLs. Some of the low-wattage, self-ballasted CMH products may have low power factors, so harmonic distortion and high neutral currents could be a concern if they’re deployed in high concentrations (check the lamp specifications for power factor).
Compact fluorescent lamps. CFLs aren’t a good choice for track lighting applications where you need concentrated beams of light, but these lamps are suitable for track lights used for flood-type light distributions and wall-washing. CFLs are also of limited value when dimming is necessary; dimmable CFLs cost more, and they generally don’t dim as deeply or as smoothly as halogen lamps. Fluorescent lamp track heads often require baffles to reduce glare for shoppers or room occupants.
Light-emitting diodes. LEDs have a number of properties that make them good candidates for track lighting applications. Because LED light output is directional, manufacturers can theoretically design the systems to match the light distribution patterns of conventional lamps or to provide new ones. However, it’s important to test products to make sure that they provide the desired light spread. LEDs emit neither ultraviolet (UV) nor IR radiation, so they can be used in museums and other areas with UV-sensitive objects as well as in grocery stores and other applications where objects are sensitive to heat. LEDs in track lighting come in two general forms: Directional LED bulbs, such as PAR lamps, can be installed in track fixtures, or track lights may come with integral LEDs built in. The biggest challenge for LEDs is to replace small halogen lamps such as the MR16 because it’s difficult for LEDs to dissipate the heat that they generate in a small package. However LED products are available to replace MR16s of up to 50 W.
Track lights for energy-efficient lamps are similar to track lights for halogen lamps (Figure 1). The track can be recessed into the ceiling, mounted to the surface of the ceiling, or suspended from the ceiling in a configuration known as a pendant mount. The track head—which includes the lamp housing, lamp, socket, and a reflector cone—moves along the track and may be integrated into the track or suspended in a pendant mount. In addition, some individual track lights can be connected directly to a junction box. Ballasts are typically housed in the track head, although they may also be recessed into the ceiling plenum. Track lights also offer options for switching individual lamps or groups of lamps.
Figure 1: LED track lighting fixture
Track lights for energy-efficient lamps are similar to those for halogen lamps. This light-emitting diode (LED) fixture was a prizewinner at the Next Generation Luminaires competition.