Without a typical light kit ceiling fan energy efficiency is at an optimal level. However, installing a standard ceiling fan light kit will draw more energy than a ceiling fan motor. Adding an Energy Star rated lighting kit to your ceiling fan will cut the energy used in half compared to that of a standard light kit. Additional energy savings can be made by purchasing a ceiling fan with an Energy Star rating which can move the air up to 20% more efficiently than a standard fan. Many leading manufacturers offer both ceiling fans and light kits with the Energy Star rating and prominently display it.
Additional energy savings can be had by simply turning the ceiling fan and lights off when you leave the room. Using the lights and fan in a reasonable manner, constantly adjusting the speed of the blades and turning the lights on and off repeatedly will use more energy than letting the fan run at a constant level.