thermostat that learns your daily habits over time

Nest - the Learning Thermostat

Meet the only thermostat that improves with time.
No more programming, no more constantly changing the temperature. The NestTM Learning ThermostatTM programs itself in a week to keep you comfortable and save energy.

Teach Nest to save.
Nest will do what you tell it, so teach it energy saving habits: turn the temperature down at night or when you leave the house, and don’t turn the temperature too high or low.

Energy saving features like Auto-Away™ and Energy History will become available as Nest learns.
Auto-Away turns heating and cooling down automatically when no one is home, saving energy when you don’t need it. Energy History shows you how much energy you’ve used daily.

Source: nest.comAdded: 25 October 2011