Studies show that people conserve more energy when they can see their usage in real time. The Maestro eco-minder dimmer operates on a similar principle. It features an LED display that changes from red to green when homeowners are saving energy by at least 15 percent. The green light moves down to show additional energy savings. It comes in white, almond, and ivory. Cost: $45.50. Lutron Electronics. 888-588-7661.