Initial Design for my SmartHome project

I have prepared an initial design for my Smart Home. The first version of the system will simply be able to detect the temperature in the house and turn the heating on or off.

I chose this design on the basis that I should concentrate on a single use case at first. I also wanted to make maximum use of the equipment I already have installed (all the items in green are already installed and only the items in white remain to be ordered). I also have a number of redundant communication paths because this is advised in the Insteon whitepaper.

As always, I would welcome feedback from people with more experience in this area.