As Nest demonstrated time and again. Their thermostats had a defect at one point (not sure if it was ever actually fixed) where if your heating or cooling syst

As Nest demonstrated time and again. Their thermostats had a defect at one point (not sure if it was ever actually fixed) where if your heating or cooling system caused a surge in your wiring, your nest would get stuck with both heating and cooling at full blast, or something equally silly. The Nest thermostat was certainly not designed to fail safely or sanely.