I'm assuming after reading the owner's manual that the batteries are required. I purchased this 80 dollar thermostat at a garage sale for 5 dollars in an unopened box. So i thought it might be good futureproofing for my home. I had a very nice high efficiency Rheem furnace installed a few years ago. Just using the old round dial thermostat.
All I want out of the new high tech programmable Honeywell for the time being is ultra basic set-and-forget heat. I don't care at all about losing settings in a power outage. I hate the idea of complicating my life with having to worry about batteries going out and replacing them regularly. Why can't I just put a 120vac/3vdc transformer in the basement and run 3vcd through two of the unused wires in the 18/5 and connect the wires to the battery terminals inside the thermostat? Does connecting the 'C' wire power this thermostat without the need for the battery backup?
Or is there a way that honeywell has provided for me to do this that I don't know about?