I&#x27;m curious why the nest can&#x27;t do exactly that.  Have a simple microcontroller running a thermostat, with hard low, soft low, hard high, soft high.  Then let the brain twiddle the soft low&#x2F;high all it likes.  If the brain goes missing, the micro just carries on brainless with the previous settings.  If the brain really screws the pooch, at least the hard low can kick in somewhere before pipes burst.<p>It seems like a safety-net would be high-school easy, and at least let them claim they&#x27;ve learnt from their mistakes.