When your lights are on and you leave the room, do you shut them off or leave them on? Outside of your home, do you use motion sensor lights or lights that stay on all night? Leaving lights on when and where it is not needed is very wasteful. According to the International Dark Sky Association, in the United States alone for an entire year, outdoor lighting uses 120 terawatt-hours of energy to illuminate streets and parking lots. This is enough energy to meet New York City’s total electricity needed for two years! Their research states that 30 percent of all outdoor lighting in the United States is wasted, especially if the lights are not shielded. This adds up to be about $3.3 billion, which is enough money to fund an annual trip to Mars. This waste also causes the release of 21 million tons of carbon dioxide per year, which is adding to the problems of climate change. In order to make up for this release of carbon dioxide, we would have to plant 875 million trees annually. However, there are a few ways that we can help reduce this waste.
It is highly recommended that any outdoor lights for homes or illuminating streets use quality lighting. This could cut energy use by 60-70 percent and help save billions of dollars and cut carbon emissions. The International Dark Sky Association recommends installing LEDs and compact fluorescents (CFLs) because they can help reduce energy use and protect the environment. These lights help lower carbon emissions by reducing the demand for electricity. CFLs are very efficient, but it is complicated to calculate their conservation. The rule of thumb when using these lights is if you are leaving a room for less than 15 minutes, keep them on; but if you are leaving the room for more than 15 minutes, turn them off. The operating life of CFLs is affected by the number of times that it is turned on and off. LEDs are unaffected by the number of times you turn them on and off and have no negative effects on their operational lifetime. They are very small light bulbs that fit into an electrical circuit and do not have a filament that burns out, unlike the traditional incandescent bulbs. LEDs do not become very warm and emit a variety of colors such as red, yellow, green, or white lights. Only warm-white or filtered LEDs should be used. They produce the same amount of light and color rendition without emitting excessive amounts of blue light. These lights have improved in quality and fallen in prices, replacing many of the outdoor lighting in communities around the world. However, because LEDs are safer for the environment and do not use as much energy, do not give in to the temptation to over-light. You should continue to be shutting your lights off when they are not necessary.
Another way to reduce energy and light pollution is to make sure that outdoor lighting is fully shielded and direct light is only where it is needed. Fully shielded lights can produce the same amount of light on the ground as unshielded ones, but with less energy and cost. Outdoor lights should only be pointed downward and not toward the sky. When light is emitted into the sky, this is what causes sky glow. According to the Lighting Research Center, sky glow is of most concern to astronomers because it produces excessive light to dark areas of the sky and reduces their ability to view celestial objects. You should also use dimmers, timers, or motion sensors on your outdoor lights to ensure dark areas and save energy. This will make sure that lights are on only when necessary.
Another way to reduce the harmful costs of light pollution is to turn your lights off whenever you can. You must try to reduce unnecessary indoor lighting. This goes for office buildings, homes, and stores. Many office buildings keep their lights on at night. Use the sunlight to your advantage and try not to turn on lights during the day. Keep your curtains and shades open to provide natural light. Decorating and painting rooms with brighter colors helps to reflect the natural light.
Always remember, helping to reduce light pollution starts at your doorstep.
The Energy Cost of Light Pollution
In school, I remember the same two basic lessons being pounded into our heads during the environment units- turn off the water when you brush your teeth and turn off the lights when you leave the room. Every once in a while I see a girl in the bathroom standing over the sink with the water on at full power and die a little bit inside but I have found that most people know about that one. As for the lights, the repercussions you mentioned were not things that I normally think of when I turn off the lights. I usually do it to save the energy (electricity costs money and I like to live on the Earth) but not of the skyglow and such. It will definitely be a forerunning thought the next time I leave the room and debate whether or not to turn off the lights for a few minutes.
I had never heard of CFLs before and thought that it was very interesting that their operating life depends on the number of times they’ve been turned on or off. I knew that turning off the lights when you leave the room is important, but I had no idea about the numbers behind energy wastage. The context that you provide for the numbers is very helpful because it’s easy to understand that $3.3 billion is a lot of money, but I couldn’t grasp literally how much money it is.
I honestly didn’t know why so many people around me have been using LED lights, because I think they’re very harsh, but I didn’t know they were more environmentally friendly. I might have to consider that the next time I buy a lamp!