An ecobee wouldn’t be cheaper, I got this through my energy provider for 30 bucks after a ton of rebates and the ecobee was 150 vs 30 for the nest. For the new wiring, would the 3rd wire be where the others are, or is it a seaprete box? I have natural gas to heat my home if that’s needed. I can definitely do this myself as the hardest parts seem to be the fishing and finding the box. Also, can u send me a link for the wiring u mentioned? I either can’t find it or im searching the wrong words. Would this work? https://www.amazon.com/dp/B00W0JW20A/ref=cm_sw_r_cp_api_i_3BhGFbWQX1PAE