In recent years, ballast manufacturers have begun marketing a premium fluorescent ballast called a “high-efficiency ballast” for operation of 4-foot T8 lamps. A high-efficiency ballast provides the same level of light output as a standard electronic ballast but does it with 2-–5 fewer watts. For a cost adder of about 10-–20 percent, the ballast can add energy savings of up to 7 percent.
For example, a lighting system consisting of a .77 ballast factor operating two T8 lamps may draw 51W with a standard ballast and 47W with a high-efficiency ballast, resulting in savings of 4W.
One manufacturer averages savings to a dollar per lamp per year. Doing some quick math, that would be a lamp operating 2,500 hours per year (10 hours per day, five days per week, 50 weeks per year) at a cost of 10 cents per kilowatt-hour (kWh). That’s reasonable.
Now, suppose we install two high-efficiency ballasts driving four T8 lamps in fixtures mounted on 10-foot-by-10-foot centers (100 square-foot area). The use of high-efficiency ballasts would add about 3 to 6 cents per square foot to the cost of the project while reducing annual energy costs by about 4 cents per square foot, generating a simple payback of 8–16 months. Such combinations can reduce system watts by a total of more than 45 percent when upgrading older T12 systems and 20–30 percent when replacing standard T8 systems.
High-efficiency ballasts are, therefore, popular for retrofits because they offer a relatively low-risk way to increase energy savings while providing light levels equivalent to a typical 34W T12 system. The ballasts suit almost any commercial application that is suited for 4-foot T8 lamps operated by standard electronic ballasts.
The ballast can be specified as instant or programmed start. High-efficiency programmed-start ballasts, which can offer the same efficiency as standard instant-start ballasts, reduce wear and tear on the lamp that occurs during startup, which can maximize lamp life in frequently switched applications, such as occupancy sensor installations.
The ballast can be specified as low (less than .86), normal (.86–1) and high (greater than 1) ballast factor, providing flexibility of selection of light levels and utility in a broad range of applications, including high-bay spaces. Many ballasts offer universal-voltage operation, simplifying installation for contractors. Both fixed-output and dimmable models are available. And some ballasts have features, such as anti-striation and anti-arcing, which enhance safety and reduce concerns about maintenance.
A major problem with high-efficiency ballasts, however, has historically been a clear definition of just what this type of ballast is and how to recognize one among a marketing clutter in which every electronic ballast is called a “high-efficiency” product. To provide clarity and formally recognize the industry’s most efficient ballasts for 4-foot T8 lamps, the National Electrical Manufacturers Association (NEMA) launched the Premium Ballast program in 2008. The program, based on the successful NEMA Premium model for electric motors and transformers, creates an efficiency target established by Consortium for Energy Efficiency specifications and recognizes ballasts that meet it with a special logo that can be printed on the ballast label.
Advance (now Philips Lighting Electronics), GE, Osram Sylvania, Robertson Worldwide and Universal Lighting Technologies all have certified high-efficiency products as NEMA Premium Ballasts. NEMA has published a list of these products in a PDF document titled “NEMA Premium Electronic Ballast Program,” which is available on its Web site.
NEMA advises the following specification language for retrofit or spot replacement: “Ballast shall be NEMA Premium electronic ballast (do not substitute).” Then, specify the starting method, number of lamps (1–4) and ballast factor.
The NEMA Premium Ballast program currently covers electronic ballasts for operation of 4-foot T8 lamps but may expand in the future to cover T4 and T5 ballasts, HID ballasts and LED drivers and power supplies.
DILOUIE, a lighting industry journalist, analyst and marketing consultant, is principal of ZING Communications. He can be reached at www.zinginc.com.