“The federally funded National Optical Astronomy Observatory (NOAO) reports that poorly-aimed, unshielded outdoor lights waste $2 billion (17 kilowatt-hours) of energy in the U.S. each year.”
So what can be done?
“According to the McDonald Observatory’s Dark Skies Initiative (DSI), the solution to light pollution is 90 percent education and 10 percent technology. “We can reclaim vast amounts of energy currently wasted inadvertently into the night sky...by using light fixtures that are shielded to reflect light down where it is needed, as well as using the smallest number of lights and lowest wattage bulbs necessary to effectively light an area,” says DSI. Leading by example through the installation of downward-pointing outdoor light fixtures is a great place for home and building owners to start: “Once people see it in action, and understand its implications for cost savings and enhanced visibility, they are far more likely to adopt good lighting practices on their own.” “