For outlets certain to become dedicated charging stations, consider installing a Combination USB Charger With Tamper-Resistant Receptacle. Its twin USB charging ports add capacity and eliminate the need for a bulky adaptor. According to the manufacturer, using this receptacle rather than a traditional charger to charge a cellphone can save about $30 per year in electricity. It costs about $18. Cooper Wiring Devices, 866/853-4293,