Originally Posted by SLOweather
Yes, you can.
Wow, I'm surprised at this answer. I've seen this discussed dozens of times and always heard that this was not possible. Interesting.
Well, I did a little more reading and see that if you buy a Thermostat that can run off of battery power it is possible to do this.
In my research I found folks that have done this and have it working flawlessly, but others have all manor of AC control issues.
But it's good to know it's possible.
I found a YouTube video that looks to show you how: