tcdent didn't say redundancy for a thermostat. For example, a fireplace and some wood is redundancy that covers both thermostat failures and power failures. If

tcdent didn't say redundancy for a thermostat. For example, a fireplace and some wood is redundancy that covers both thermostat failures and power failures. If you live in dangerous weather as mentioned in the original comment, it would be stupid not to have a Plan B.