Next on the list: tackling heating and cooling costs. About half of energy costs can be attributed to heating and cooling. Programmable thermostats help households save about $180 a year. But instead of remembering to set the right temperatures, Nest Labs, founded by Tony Fadell, best known for designing the iPod, introduced a learning thermostat that adapts to households' behaviors, schedules and preferences, automatically turning down heating or cooling when nobody's home. In addition, the thermostat will suggest more energy-efficient temperatures to help homes further cut costs. Nest, which connects to homes' WiFi networks, can be adjusted remotely via laptop, smartphone or tablet.