Sure, at least for traditional two-wire thermostats that turn on when the circuit is closed: connect them in parallel.<p>The Nest is so obviously a product designed in warm California—not anywhere that sees truly hard winter. If it were designed well, it would fail safe (furnace on). I&#x27;d rather have a hefty heating bill from my furnace running 24&#x2F;7 than have all of the pipes in my house freeze and break. If I ever install a Nest or other smart thermostat, it will be in parallel to the bimetallic-strip-and-mercury-switch from forty years ago.