Technologies > METAL HALIDE TRACKLIGHTS

 

Description: Traditionally, incandescent/halogen has been the preferred light source for track, although compact fluorescent has made in-roads due to its efficiency. About 10 years ago, manufacturers began offering low-wattage metal halide lamps, which quickly became a viable alternative.

Today’s low-wattage metal halide lamps come in very small sizes, are typically ceramic metal halide for improved lamp performance, and are operated by integral electronic ballasts. Otherwise, the metal halide lamp/ballast track-head attaches to line-voltage track systems like incandescent track-heads, with no special wiring and little learning curve required by the installer.

Characteristics: Metal halide lamp and ballast offerings are rapidly expanding. For indoor use, the wattage ranges from 20W to 100W. The fixture types available include accents as well as wall washers and floods incorporating PAR, T4, T6, ED17 and the newer MR16 and CDM-111 lamps. While manufacturers say the T6 G12-base lamp in 39W and 70W is the most popular for new construction, interest is growing in smaller lamps such as the T4 and MR16 in lower wattages. Most of these lamps are ceramic metal halide, which provide better color rendering, color stability and lumen maintenance than standard metal halide lamps.

Advantages: Advantages of low-wattage metal halide include higher efficiency and longer lamp life, both of which can reduce owner operating costs. Metal halide track lighting can replace incandescent spotlights on a one-to-one basis and save 50-70 percent of the energy. Some manufacturers offer metal halide fixtures as direct replacements. Alternatively, metal halide lighting can increase illumination 2-3 times at the same energy level as incandescent, enabling the same track to generate more light. For example, one 70W metal halide track-head can replace up to three 90W incandescent track-heads. Additionally, the average service life of a metal halide lamp is 10,000-15,000 hours compared to 3,000-4,000 for a typical incandescent or halogen lamp.

It is difficult to maintain existing light levels and meet tough new energy codes without using metal halide track lighting, particularly the latest ASHRAE/IES 90.1-2004, which reduces power allowances in retail spaces from 1.9W/sq.ft. (1999/2001) to 1.5W/sq.ft. But while it does help, it is not the complete solution since most codes assess track energy usage based on linear feet of track, not actual consumption. Typically, the installation must combine metal halide track lighting with a current-limiting device as prescribed in the energy codes. This device may be offered by the track manufacturer as an option for their systems.

Metal halide track offers other benefits. Compared to compact fluorescent, metal halide can also offer greater color (if a ceramic metal halide lamp) and sparkle and depth in the visual field (because it’s a point source). Another aesthetic benefit is potential reduction of track-heads, resulting in a cleaner look for the space. Due to significantly reduced heat output, air-conditioning requirements can be reduced, and lighted objects can be less affected by heat generated by the lighting system.

Disadvantages: One disadvantage is initial cost—metal halide lamps and track-heads can cost up to five times more to purchase than halogen and incandescent track lighting, and therefore must be justified from a payback or life-cycle cost point of view.

In addition, most metal halide track lighting is not dimmable (except with a limited offering of dimmable ballasts), and is not instant-on (requires a warm-up period), limiting application with occupancy sensors and other shut-off controls. And metal halide is generally not considered suitable for very tight beam spreads (<7°).

 

See also:

Ceramic Metal Halide Lamps

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