Any body know of a reliable smart thermostat that does NOT require a “C” wire or am I wasting my time looking for one?
GoControl Z-Wave can be operated on 4 AA batteries and they last for over a year. You can also power it via a C wire.
There are many battery operated thermostats, including Honeywell, GoControl, Linear etc - the batteries last about 3-6 months depending on usage.
Alternatively you can use the Venstar add-a-wire system shown here to convert an existing wire into a C-Wire, we have it here in the lab and it works great:
Another option if you want zigbee is the Zen thermostat. It can be used without a C wire on most low-voltage systems, and is available in both the US and Europe.
You should be able to find more discussion of it in the forum, it’s been pretty popular.
Are you certain your wiring bundle doesn’t have an extra wire in it that can be used as C if hooked up properly?
Positive. I’ve checked and double checked.