I want to add new thermostats in my home. Luckily, the wiring to my thermostat has an unused wire in the bundle for the required "C-Wire". It has R,G,Y,W, and an unused blue. The thermostat wiring goes to the air handler which appears to not have any 24V terminal I can use.

The air handler is connected to the furnace with a R,W and unused green wire. (I haven't traced the a/c wiring yet). The furnace control has an unused 24V terminal inside it.

Is it sensible to wire the unused green in the furnace to the 24V terminal, and then pigtail that green to the blue in the Air handler to supply the thermostat 24V on that blue?

I guess what I'm asking in a general sense: does it matter from where the 24V 'c-wire' is sourced ?

(I can and will post more pics and schematics if needed when I get back home).


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