A:Answer Compatible with Alexa? Supposedly, but I have never been able to get Alexa to control my Nest (not Google-Nest) thermostat. Buy a google home mini to use if alexa won't work. About that "c-wire'; My old non-google nest thermostat-E worked without a C wire for several years. I just replaced it with a new google-nest thermostat E a few weeks ago after the wifi transmitter failed, and so far, it is working without the C wire. HOWEVER, I have another residence that I installed the more expensive non-google-nest learning Thermostat and it has never been able to work without the C wire for longer than a week, maybe less. Maybe the newer google-nest branded learning thermostat won't have that problem, but I'm not sure. IF YOU DON'T HAVE A C-WIRE, I STRONGLY SUGGEST YOU BUY A PRODUCT LIKE VENSTAR'S OR HONEYWELL'S "ADD A WIRE" PRODUCT. But I would check your wiring first. I found my furnace had an unused fifth wire in the cable, I just needed to hook it up at both ends.