Smart thermostat now tracks energy usage history

The widely coveted Nest Learning Thermostat, which was sold out last fall before it managed to hit market early this year, has been updated with several pretty smart new features.

The $249 gadget from Nest Labs can now provide homeowners with a granular view of your energy usage for the past 10 days. You can see when heating or cooling was turned off (or on), how energy usage from the past week compares with what is going on right now, how weather played a role, and so on. You can look at this information on the device display or by using one of the iOS or Android mobile apps or Web apps that accompanies the technology.

Nest Learning Thermostat also has been updated with a feature called Airwave. You know how your air-conditioning system will often stay on for up to 10 minutes after you actually turn it off? This feature works in conjunction with an energy-efficient fan to make sure that cold air isn't wasted, pushing it throughout the house. Airwave automatically is switched on when the temperature outside is high and the humidity is low, according to the product update details.

If you already have a Nest Learning Thermostat (people in all 50 states do), the updates will be delivered to your device via a wireless update.