I have installed 3 temperature sensors, one on the first floor, and two on the second floor (one in the master bedroom and one in my home office). Each sensor publishes updates to a Topic, similar with this http://cloudutilsj.appspot.com/topic/c7ba6e1b6c849d37.
Then I have created a Google Spreadsheet where I listed all rooms that have temperature sensors, the public URIs of the sensors, the target temperatures for those rooms and the schedule. This way I can easily express the fact that different rooms need to be comfortable only between certain hours of the day. In the past, achieving comfortable temperature in my home office for example was difficult because the thermostat was on the first floor thus unaware of the actual temperature in the office for optimal control. Not anymore.
Once I had this in place I published the Spreadsheet as CSV and I created a program that reads the published CSV and adjusts the thermostat for optimal control. Beautiful!
Now I'm looking for controllable floor vent registers, but so far I could not find any. If you are aware of such a product please drop me a line at contact at smartergadgetsstore.com. My goal is to have the vents monitor the spreadsheet as well and only blow air into the rooms that are "active" at a certain time.
