This morning, we noticed that although the library was completely empty, all the lights and fans were up and running. A lot of energy was being wasted, so we decided to determine just how much energy was being consumed in the library. Because it is difficult to measure the energy usage of the fans, we decided to just estimate the energy usage of the lights instead. Equipped with the knowledge that each light has roughly 80 Watts, we estimated that the library uses roughly 16,160 Watts per hour, or roughly 16 kWh. Because 1 kWh accounts for $0.16 in energy costs, 16 kWh costs the school about $2.50 an hour. We realized that this was something that needed to be fixed, so we began to brainstorm ideas of how to solve it. This is a costly problem that can be solved with lights that turn on only when the library is in use, so that the energy can be conserved when school is not in session.