Metal halide lamp fixtures are commonly used in industrial buildings and high-ceiling commercial applications such as gymnasiums and big-box retail stores. Metal halide lamps are also used in some low-ceiling applications and in street lights and other high-light-output applications.
In December 2007, Congress enacted EISA, setting initial minimum efficiency standards for 150-500 W metal halide lamp fixtures. The standard became effective in January 2009, requiring a minimum ballast efficiency of 88% for pulse start ballasts and a minimum ballast efficiency of 94% for magnetic probe start ballasts.
In February 2014, DOE published updated standards for metal halide lamp fixtures. The standards apply to fixtures designed to operate lamps with wattages between 50 W and 1000 W. The new standards would improve the efficiency of the ballasts that are used to drive the metal halide lamps. The efficiency standards can be met by the use of improved magnetic ballasts which consist of metal coils wrapped around a magnetic core. The final standards for 100-150 W fixtures are weaker than those initially proposed by DOE. Had DOE stayed with the proposed levels, the higher efficiency level could have been met with the use of cutting-edge electronic ballasts, which use electronic circuitry instead of a core and coil. The new standards also prohibit the use of probe-start ballasts in fixtures greater than 500 W. Pulse-start lamps have better lumen maintenance than probe-start lamps, which means that a customer can replace probe-start fixtures with lower-wattage or fewer pulse-start fixtures while maintaining the same light output.
According to DOE, products meeting the new standards sold over thirty years will save light fixture buyers more than $1.1 billion, reduce CO2 emissions by about 25 million metric tons, and reduce electricity use by 46 to 58 billion kWh, or about enough to meet the total electricity needs of 4 to 5 million typical U.S. households for one year. the new standards take effect in Feb 2017.
The California Energy Commission adopted a two-tiered standard for metal halide lamp fixtures: the Tier 1 standards became effective January 1, 2010, and the Tier 2 standard became effective January 1, 2015. The California standards are exempt from federal preemption.
The energy losses in typical magnetic ballasts are about 10-30% depending on the wattage. High-efficiency electronic ballasts can cut those losses in half. About 2.7 million metal halide lamp fixtures are shipped annually.