Energy Efficient Lamp and Ballast Choices
REPORT PREPARED FOR enLIGHTen AMERICA
Experts associated with the enLIGHTen America campaign sponsored by the National Electrical Manufacturers Association (NEMA) recommend considering a complete system upgrade, redoing both the lamp, ballast and control systems at the same time to maximize savings and efficiency. That may well be true even for systems installed during the past decade.
“Advancements in lamp, ballast and control technologies have allowed lighting users to truly ‘have it all’ and benefit from the most energy-efficient, cost-effective, long-lasting and high-quality lighting systems to date,” says Susan Bloom, director of corporate communications for Philips Lighting. “These developments can reduce lighting costs by as much as 30 to 50 percent and total facility energy consumption and costs by up to 20 to 25 percent.”
According to enLIGHTen America, many commercial operations have ballast systems with a life that is typically 10 to 13 years of use.
At the end of ballasts’ life cycle, organizations can reduce energy use by relamping with lower wattage lamps and electronic ballasts. Additional options are to select ballasts designed to operate the lamps at even lower wattages and install controls — a good route for optimizing lighting efficiency in any space. In either instance, total wattage is reduced, lowering the annual energy spend for lighting.
Range of Lamp Choices
For many organizations, replacing older T8 systems with high-efficiency versions nets significant costs savings without too much expense. “Advances in T8 technology have substantially improved system efficiency,” says Mary Beth Gotti, manager of the GE Lighting and Electrical Institute for GE Consumer & Industrial.
According to enLIGHTen America, T8 reduced wattage lamps fall into the following categories:
30W T8 Lamps: For instant start and programmed start ballasts, 30W T8 systems are available. Because of the high population of instant start ballasts already in the field, switching to this energy-saving lamp can be a simple substitution.
28W T8 Lamps: 28W T8 lamps are available for instant start and programmed start ballasts; when operated with a reduced-power (low light output) ballast, power consumption is 24 percent lower than a standard reduced-power instant start system with a 6 percent reduction in light output.
25W T8 Lamps: 25W T8 lamps with a compatible electronic ballast can be installed for additional energy savings.
It should be noted that reduced wattage T8 lamps, like their T12 counterparts, have application restrictions such as minimum starting voltages, temperature sensitivity, dimming and inverter operation that do not apply to full wattage lamps. Check with the manufacturer to be sure that an application is appropriate for these lamps.
Super T8 Lamps: Super T8 lamps are 32W T8 lamps but with a barrier-coat design, high lumen maintenance, long service life and high light output — more than 3,100 initial lumens as opposed to 2,850 for a typical standard T8.
“High-efficiency T8 technology just keeps getting better,” says Susan Anderson, manager of energy relations at Osram Sylvania. “In recent years, we have optimized lumen output, lumen maintenance and lamp life to provide high lumen lamps — super T8 lamps — that can be paired with lower wattage/low ballast factor electronic ballasts to reduce energy usage while delivering appropriate light levels.”
As already noted, reduced-wattage T8 lamps are not typically compatible with dimming ballasts: however, if dimming is desired or required, facility executives should consider using high -lumen, full wattage T8 lamps.
T5 lamps present another option for efficiency. “Lately we’ve been seeing a phenomenal response for T5 lamps with electronic ballasts,” Ward says.
High-efficiency T5 systems offer an alternative to T8 and traditional HID. Delivering high-lumen output, new T5 HO (high output) fluorescent lamps provide an energy-efficient option for industrial and high-bay applications previously dominated by HID technology. The smaller diameter of T5 lamps contributes to luminaire efficiency.
“Compared to 400-watt universally mounted metal halide systems, T5 HO systems, for example, can provide 44 percent energy savings and deliver as much as 75 percent longer lamp life, as well as associated reductions in maintenance and relamping costs,” Bloom says.
LEDs are another innovative technology that facility executives should consider. “We’re beginning to see the emergence of LED, especially white light LEDs,” Ward says. “Technology advances are allowing LED systems to rival the efficiencies of some fluorescent and high intensity discharged (HID) systems.”
“Operating and maintenance costs, as well as carbon footprints, are minimized by LEDs,” says Bill Morreal, vice president of marketing for Juno Lighting Group. “LEDs can offer a lifespan of over 50,000 hours, so these systems can last up to 10 years, operating 12 hours a day.”
In addition to long life, LEDs give off very little heat. They are increasingly popular as replacements for incandescents in such applications as exit signs and traffic signals, as well as specialty applications like retail freezers.
LEDs work better in some applications than others. Anderson recommends them for use in applications such as refrigeration cases, task or undercabinet and display case lighting, recessed downlighting, walkway and landscape lighting. In some cases they can also be used for lighting roadways and outdoor areas.
In places where incandescent or CFL downlights were previously used, LED replacements are often ideal. According to Morreal, LEDs are available in warm 3000K, mid-range 4100K and even cooler color temperatures.
Gains in Ballast Technology
During the last decade, high-efficiency ballasts have become readily available. Generally speaking, they produce the same level of light output as standard ballasts, but do so more efficiently, saving 2 to 5 watts per ballast.
Using high-efficiency T8 ballasts can save an estimated $1 per lamp per year. They are also ideal for facility executives who want to retrofit a space and upgrade to a more efficient system without making the switch to T5.
When high-efficiency T8 ballasts are used with 25W to 30W energy-saving T8 lamps, the combination can reduce energy use by the lighting system up to 48 percent when compared to older T12 systems, according to NEMA.
Additionally, many high-efficiency ballasts are available with universal input voltage to simplify stocking requirements and replacement.
According to NEMA, universal-voltage ballasts adapt automatically for voltages in a wide range, including standard voltages of 120V and 277V. This means fewer ballast models can handle a greater number of applications, reducing inventory requirements.
Fluorescent lamps aren’t the only technology to have gained from developments with electronic ballasts. One concern with older generations of probe start metal halide lamps was lumen depreciation. With electronic technology, new pulse start metal halide lamps may be able to achieve 90 percent lumen maintenance over a 20,000-hour lamp replacement cycle, says Bryant. With improved lumen maintenance, lower wattage systems can be used and that means energy can be saved.