“It’s best not to try to replace your thermostat during a time ... “And hold on to the old thermostat. If you mess things up ...

Once you figure out what type you need, remove the thermostat from the wall and find the battery compartment, replace the old ones with new ones, and return the battery compartment to the thermostat.

His teardown revealed burned insulation, bare conductors, and scorched plastic on the not-so-old unit; bearing a 2008 date code, the thermostat must have replaced one of the originals.