My contributions to the February issue of tED Magazine included an update on metal halide rules. Reprinted with permission.

On February 10, 2017, U.S. Department of Energy (DOE) rules take effect that regulate the efficiency of metal halide lamp ballasts sold as part of new luminaires.

These rules update existing energy efficiency standards created by the Energy Independence and Security Act of 2007. The previous rules virtually eliminated probe-start lamps and ballasts from new medium-wattage (150-500W) luminaires, a segment of the market representing the majority of metal halide shipments.

The new rules establish minimum ballast efficiency standards for luminaires based on ballast type, location (indoor or outdoor) and rated lamp wattage (50-100, 101-149, 150-250, 251-500, 501-1000). DOE essentially modified standards for the medium-wattage segment while establishing new standards for the low-wattage (50-149W) and high-wattage (501-1000W) segments of the market.

Two of the existing exemptions remain in effect. These include 480V electronic ballasts and regulated-lag ballasts limited to applications such as heavy industrial, security and street and tunnel lighting. However, metal halide luminaires rated only for 150W lamps, rated for use in wet locations, and containing a ballast rated at ambient air temperatures higher than 50°C are no longer exempted.

Otherwise, the rules do not cover 1001-2000W lamp ballasts. They also do not cover replacement ballasts sold to maintain luminaires already installed.

For the past three years, manufacturers have evaluated their products on a case-by-case basis and continued, redesigned or discontinued them. Given metal halide is a declining technology under strong direct competition by solid-state lighting, a significant number of products may have been discontinued. In other cases, luminaires may have been redesigned for a different ballast and then retested. The result may be gaps in availability and an aftermarket mixing designs and redesigns. Check with the luminaire manufacturer about availability.

Compliant ballast options include pulse-start magnetic and electronic. Pulse-start magnetic ballasts provide the benefits of higher efficiency, superior lumen maintenance and greater color stability than probe-start ballasts. Electronic ballasts operate at an even higher efficiency, resulting in about 10 percent energy savings compared to magnetic ballasts. They may also improve lumen maintenance, extend lamp life and offer other features such as dimming. However, their higher cost and lower degree of ruggedness compared to magnetic ballasts have limited market penetration. The ballast may be high-frequency or low-frequency square wave. As high-frequency electronic metal halide ballasts are not compatible with all metal halide lamps, the lamp and ballast must be properly matched to avoid issues.

When it released the rule in 2014, DOE estimated energy savings would recoup the cost premium in 4.5 to nearly 20 years, depending on the luminaire and other factors. An exception was 1000W lamp ballasts with an estimated payback of less than a year.

For more information, consult the luminaire manufacturers.