Complains about not having a common wire for an ecobee, cobbles together a separate box with a USB cable draping down around the door jamb - love it :)
As others pointed out, put a plain old bi-metallic thermostat in parallel with these confounded computerized thermostat as a fail safe. Frozen pipes are no joke! I have one in parallel with my Nest and would probably do it with a "normal" thermostat anyway as I've had those fail in weird ways in the past too. Redundancy on critical systems is never a bad thing.
As others pointed out, put a plain old bi-metallic thermostat in parallel with these confounded computerized thermostat as a fail safe. Frozen pipes are no joke! I have one in parallel with my Nest and would probably do it with a "normal" thermostat anyway as I've had those fail in weird ways in the past too. Redundancy on critical systems is never a bad thing.