jack2008,
Welcome to the forum.
I've been looking at your post for some time now - sorry for the delay.
While I applaud your desire to save energy, I must say that I'm not a fan of using home automation for HVAC systems. These systems are rather complex with various feedback controls and safety devices. I would normally propose that you install the appropriate design HVAC control system to meet your needs (i.e. put the smarts in the heating system, don't override it with an automation system).
As I reread your post, you appear to asking if it would be possible to use a commercial thermostat along with a motion sensor to jump modes from un-occupied to occupied. That may be possible and not too objectionable since the heating system is still in control.
You do have a number of challenges -
- You mentioned a commercial boiler - Is this a radiant heat system or boiler/forced air system. If the system is radiant, the recovery time will likely be excessive (i.e. when the occupants arrive and trigger the system they will need to wait a long time for the room(s) to become comfortable).
- Do you have multiple zones/ sensing locations?
- What is the electrical environment in the office? Is this a muti-office complex or a stand alone building?
Assuming that the answers to the above don't blow this project out of the water, there are a few thermostats available that offer a setback function that can be activated via RF.
Smarthome makes an Insteon based adapter that
might be linked to a Insteon RF motion sensor:
Insteon Thermostat Adapter. I say
might because the Insteon motion sensor has not yet been formally released.
There are ZWave compatible thermostats as well:
ZWave Thermostat. I am far less fluent in Zwave tech. There are ZWave motion sensors available, but you may need additional hardware to interface them to the thermostat.
I'm presenting these as options to give you an idea of what is available. You will need to check compatibility with your existing system. I did not recommend an X10 thermostat because I could not locate a device that would allow you to trigger the setback mode using a Home Automation interface. The RCS and HAI products that I have seen allow you to "Totally control" the thermostat using X10 - This I would not recommend.
Boiler