According to the US Department, of Energy, “the cost effectiveness of turning off lights depends on the type of bulb and the cost of electricity. The type of light bulb you use is important for several reasons. All light bulbs have a nominal or rated operating life, which is affected by how many times they are turned on and off. The more often they are switched on and off, the lower their operating life.” The type of lights and the price of electricity determine whether it’s best to turn lights off when you leave a room. Consider using sensors, timers and other automatic lighting controls. See energy.gov’s recommendations for when to turn off the various types of lights in your home.