I'm unsure that it requires the internet, just a router and AP to direct connect the two devices together. Furthermore, if the the furnace is the root of the CO

I'm unsure that it requires the internet, just a router and AP to direct connect the two devices together. Furthermore, if the the furnace is the root of the CO emission it would be a boon to have the nest thermometer ask for forgiveness vs ask for permission to save you from death.