Bests & Worsts Reviews from Amazon

Was impressed by all the positive reviews and joined the bandwagon and bought a Nest Generation3 Thermostat. Hooked number it up and it was impressive for about two weeks until outside temperature dipped to -10. Thermostat shut down and kept throwing error code e73. Called Nest support and after being on hold for 45 minutes finally talked to an agent who had me check wires, voltage, wifi. Finally asked me to replace with old thermostat which I no longer had. Called my HVAC guy I normally deal with thinking problem was with furnace. First thing when he arrived showed him thermostat and he just smiled and said not another one of these. He has had issues with other Nest Thermostats. He explained that the battery for these is not very big. They actually try to share a very small portion of power from your furnace circuit. He said when it gets very cold, the circuit for the air conditioner shuts down so it cannot start and I lost my power feed. He put back on a mechanical thermostat and furnace started right up. Did some checking on internet and seems to be a known issue. Nest-that is a big fail !!!!. Cost me $150 for the service call and new thermostat. Do not buy one if you live in area that gets extremely cold. Mine is going back the the vendor.