Motion sensors (occupancy sensors) automatically turn lights on and off so you only get (and pay for!) light when you need it (Photo 1). Using motion sensors can save you $100 per year. Some motion sensors need to be manually turned on but turn off automatically. They’re great for bedrooms because they won’t turn on when you move in your sleep. Some switches are installed in junction boxes; others are wireless. You can also buy light fixtures with built-in motion sensors. You’ll need special motion sensors for electronic ballasts that control CFLs. Special-order them at home centers or buy them on the internet. Use timers to control bath fans so the fan will run for a preset time to air out the room and then automatically turn off (Photo 2). You can set the length of time you want the fan to run. Be sure the timer you buy is rated for motors, not just lighting (check the label).