Consider fluorescent lighting instead of incandescent lighting. Install mercury vapor or sodium vapor lamps for large exterior or high-bay interior areas. Proper lighting is an environmental factor that is often overlooked or is given little attention during planning, construction, or maintenance of dairy facilities. Worker efficiency, safety, and comfort can be improved with proper lighting in a dairy unit. In addition, research has shown that supplementing lactating cows with 16 to 18 hours of light per day increases milk production by five to 16 percent as compared to cows exposed to 13.5 hours or less of light per day.
Factors affecting efficiency include amount of light per watt and lamp life.
Fluorescent, metal halide, and high-pressure sodium lighting systems are significantly more expensive than incandescent. However, the energy cost savings combined with longer lamp life offset the higher initial costs for energy-efficient lighting systems. The energy-efficient alternative will typically pay for itself in two years or less in dairy applications. Other characteristics to consider when selecting a lamp type are starting temperature and warm-up. The minimum starting temperature for most fluorescent lamps is 50 F. Ballasts are available that allow fluorescent lamps to start at -20 F, but costs are significantly higher than for standard ballasts.