None of our mechanical thermostats have a Calibration feature. They are only calibrated in the factory prior to shipping.
Due to the inaccuracy that comes with using a mechanical thermostat, the numbers on the front of the thermostat may not exactly match the room temperature. If this is the case, please simply ignore the numbers and adjust the set
temperature knob higher or lower to achieve the desired room temperature from your heating or cooling equipment.
On the current Line Voltage thermostats being shipped, the numbers have been removed from the cover to avoid confusion and a range is labeled “Comfort Zone”. Turn the knob either higher or lower as needed.
Mechanical thermostats are just not that accurate. If better accuracy is required, We would suggest that you upgrade to an electronic programmable thermostat.