The most important lighting effectiveness factor is the amount of light provided for the tasks being performed. Even an office manager with little training in electric illumination can quickly learn how to spot low-quality lighting almost instantly. The quality of a lighted environment depends mostly on the quality of the products used to provide the lighting. Lighting system flexibility is far more important to achieving effective lighting than it is to achieving efficient lighting. Better lighting may entitle an organization to lower insurance rates.
More effective lighting can help reduce gasoline consumption.
But lighting is for people. Turn it off and they cannot get done that which they need vision to do. Better seeing conditions help people perform their visual tasks faster, with fewer errors, among other positive effects. Just a small productivity boost can easily be worth 10 times that amount. If you provide too little, people will not be able to see as well as they otherwise could.