I'm trying to install a new thermostat that needs a C wire hookup. There are currently 4 wires running from the thermostat to the furnace, none of them are a c wire. When I look at my furnace itself it has a spot to put a c wire but it's currently being used by my whole-home humidifier.
If I run a separate 18-1 wire from my thermostat to the furnace can I just wire both the humidifier and thermostat to the one c-wire hookup?