A few weeks ago, my apartment complex installed new UtilityPRO programmable thermostats in all of the units. As part of the CPS Energy Peak Saver program. Quite a convenient little gadget, but a little creepy too. With this thermostat, CPS has the ability to modify the temperature remotely without me knowing. Although I personally couldn’t care less, I spoke with some friends who didn’t like this idea. So that got me thinking — I wonder how difficult it would be to disable this remote access.
A little googling revealed that the thermostat I had was a Honeywell UtilityPRO, which handles remote communication through the ZigBee protocol. With this knowledge in hand, I did what any good computer scientist would do and ripped the damn thing apart (carefully, of course). What follows are the steps that I followed in removing the ZigBee COM module, which in turn disabled any remote communication with the thermostat.