Track lights provide direct beams of high-quality light for use in retail displays, galleries, museums, and residences. They’re useful in places where lights need to be aimed at different angles and where the position of the light may be changed frequently. Until recently, the only light sources that could provide the right kind of illumination for track lighting were inefficient halogen lamps. However, newer light sources now provide an array of options.
Low-wattage metal halide (MH) lamps introduced in the mid-1990s gave designers and specifiers the first energy-efficient alternative. Compact fluorescent lamps are available for some types of track lighting, and LEDs have become a good choice for a growing number of applications. These lamps reduce energy use and last much longer than halogen lamps, leading to reduced lamp-replacement costs. However, the costs for energy-efficient lamps and fixtures are significantly higher than those for halogen units, so these newer technologies are most likely to be cost-effective in applications with long burn hours and where changing lamps is difficult. Advanced halogen reflector lamps that will meet federal regulations are also now available and will keep halogens in the game for a while longer.
What are the options?
Halogen lamps, CFLs, MH lamps, and LEDs are all used in track lighting (Table 1). Each has strengths and weaknesses.
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.
How to make the best choice
Compare the cost-effectiveness of halogen with other energy-efficient alternatives. The cost-effectiveness of energy-efficient options depends on the intensity of their use and on local electricity costs. Energy efficiency and long life make up for higher first costs quickly in areas and applications where electricity and maintenance costs are high and usage is most intense.
Try before you buy Alternative light sources produce different color effects than halogen lamps, and may provide a different light distribution. Make sure to test the lighting before any major conversion to be sure that the results are acceptable. In addition, because ballasted fixtures (unlike halogen fixtures) are designed to work with only one lamp wattage, it’s important to determine the right lamp size before you purchase any fixtures.
Account for lumen depreciation Halogen lamps lose less than 5% of their light from the time that they’re new to the time that they fail. MH lamps lose 10% to 40% of their rated output after 40% of their rated life. LED lamps don’t generally fail outright, but their output fades over time and the accepted definition of the end of lamp life is when output has degraded to 70% of its initial value. This phenomenon can shorten the lamp’s effective life if output becomes too dim for the application, or it can force designers to overlight the application when it’s first installed.
Avoid halogen lamps where heat can cause problems LED lamps reject most of their waste heat by conduction and therefore keep illuminated objects cooler. MH lamps and CFLs emit less IR radiation than halogen lamps do, and LEDs emit even less. Lamps with low-IR radiation can reduce the fading and drying of objects and may increase the lifetimes of some displayed objects, such as food.
Use long-life sources to minimize disruptions In applications such as retail display lighting in windows and areas tightly packed with products, long-life sources such as LEDs will reduce the frequency of relamping and therefore reduce maintenance disruptions.
Look for Energy Star–qualified LEDs or DLC-listed LED fixtures Look for Energy Star–qualified products to ensure that LED replacement lamps are of good quality. And for good quality LED track fixtures, check the DesignLights Consortium’s (DLC’s) Qualified Products List.
Don’t use MH lamps where warm-up and restrike delays could cause problems. MH lamps require a warm-up period, which can be troublesome after power interruptions or in applications where lights are frequently turned on and off. CMH lamps on electronic ballasts take 1 to 3 minutes to reach full output and as much as 10 to 20 minutes to restrike after a shutdown or power interruption.
Be sure the track can handle the weight in a retrofit. MH track lights can fit into existing tracks designed for halogen fixtures. However, magnetically ballasted MH track lights weigh considerably more than halogen units and could exceed the weight capacity of the track. Electronically ballasted fixtures weigh considerably less and may not present such a hazard.
What’s on the horizon?
LEDs continue to come down in cost as their performance improves and are becoming a cost-effective option in a growing number of applications
Who are the manufacturers?
Here’s a partial listing of companies that offer metal halide lamps and track-lighting fixtures.
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