I recently got a new boiler fitted and opted for the clever little Nest thermostat. I was a little disapointed to find the usage history only goes back 7 days and it was pretty basic, so I tapped into their API and built my own energy usage logger which live graphs can be found below.
How does it work?
Every 5 minutes the Nest API is queried and data including the current temperature, humidity, battery levels and so on is stored to a temporary SQL table. The data is then averaged out by hour, day and month and is stored permanantly in seperate database tables. The data is then pulled into graphs in my case, but could be used for all sorts of other things like automated alerts and more.
The data collected can be found below, at the moment it is displayed in the form of hourly, daily and monthly line graphs.