Wilson says the Petersens’ T-12 fluorescent bulbs generated about 70 to 80 lumens per watt of electricity, versus 104 to 110 lumens per watt for their new LED lamps. Additional energy is saved by no longer driving the fluorescent ballasts. The result: more light for less electricity.
Switching to LED lamps also resulted in no change to the Petersens’ photoperiod lighting system in their free-stall barn, which ensures 16 hours of 20 footcandles of light per day from 6:30 a.m. to 10:30 p.m. The system is regulated by a master-timer switch and a photo eye to detect daylight, and continued to function consistently after the LED lamps were installed.
Best of all, Petersen estimates that the dairy’s monthly lighting bill has been cut by more than 60 percent since the LED lamps were installed last February.
LED lighting is not exactly “new” technology, as it first was invented in the 1970s. But Kevin Janni, professor and extension engineer at the University of Minnesota, says the technology and its applications have improved tremendously in recent years. “The light spectrum and quality is much more appealing now, and products that can tolerate moisture and dust are making LED lighting a more practical option for agricultural settings,” he says.
Janni believes high-quality LED lamps are an excellent option for new dairy construction or remodeling because they are more efficient and last longer than fluorescent, metal halide or high-pressure sodium lighting options.
Wilson says the life of a well-maintained LED lamp is 50,000 hours or more, compared to 15,000 to 20,000 hours for the other common barn-lighting options. And, as a plus for outdoor and semi-outdoor settings, “they love cold,” says Wilson. “They actually function better and last longer in cold conditions. I have tested them at conditions as low as -20°F, and they performed perfectly.” He adds that LED lamps will function in extreme heat as well, but prolonged exposure to high heat (110 to 120°F) will shorten their lifespan. In addition, Wilson cites the following additional benefits of LED lighting:
• LED lights contain no gas or mercury, so government-regulated disposal is not required.
• Unlike metal halide and compact fluorescent lights, LED lights do not need to “warm up.” They produce instantaneous light as soon as they are switched on.
• Constructed of high-quality aluminum and recycled plastic, LED bulbs will not shatter like fluorescent or metal halide bulbs.