(Not all thermostats have replaceable batteries.)
- Turn the thermostat to the “Off” position.
- Make sure the fan is set to “Auto”
- Depending on the thermostat, remove the cover for the batteries, or remove the faceplate, or remove the entire thermostat from the base.
- Replace the batteries.
- Reverse whatever action you took on step 3.
- Turn the thermostat back on by setting it to “Cool” or “Heat” and adjusting the temperature accordingly.