In order to be able to control the climate of each room individually, it is essential to have a temperature sensor in every room. They also have to be located in the right location and at the right height. Typically, this means away from doors and at about 1.5m above floor level.
Retrofitting them into our existing home has proved very hard work. Using wireless sensors would make more sense in an existing building but, only if you actually have the ability to control heating and cooling on an individual room basis. In our current home we are using NOT DEFINED with Dallas DS1920 temperature sensors, to monitor the temperatures in most room. This is more of an experiment as we don't have the ability to control temperature on a room by room basis.
In a new build these can be designed in and installed and wired up quite easily.