How To Test The Thermometer In Your Thermostat

If you are not getting the heat you need, you should learn how to test the thermometer tin your thermostat. Your thermostat controls how your home is heated, cooled and ventilated. The thermometer inside your thermostat controls the signal functions of the thermostat and when it doesn’t work, you need to check it out following some simple checks and maintenance.

How to Test the Thermometer

  • If you believe the thermostat isn’t operating due to a faulty thermometer, test it.  Tape a piece of paper towel to the wall next to the thermostat and then tape a household thermometer to the paper towel. The paper towel should impede the thermometer from reading the wall temperature. You want only an air temperature reading. Wait for 15 minutes to read the thermometer. If the thermometer in the thermostat reads differently, you need to perform some thermostat maintenance. Leave your taped to the wall thermometer in place when conducting your thermostat maintenance check and adjustments.
  • Turn the thermostat off at the breaker box panel. Make sure it is off by clicking to the “Fan” setting. Obviously if it doesn’t kick on, there’s no power.
  • Clean the thermostat by removing the cover and then rubbing a piece of adhesive shelf liner or even a dollar bill between all the thermostat’s contact points.
  • Turn the power back on and repeat the thermometer test. If still not reading correctly, try changing any batteries. Check with the manufacturer’s instructions for the correct batteries to use. Once the batteries are changed, repeat your thermometer test again.
  • If the problem is that the heater or air conditioner turns off and on constantly, you probably do not have a thermometer problem. More than likely, you have a faulty heat anticipator. This is a device designed to shut the thermostat off when the room reaches your selected temperature setting. While you have the cover off, locate the center disk and move its lever control toward the “longer” setting. Sometimes a thermostat does not read properly because over time the screws attaching it o the wall loosen, making the device not level which can create faulty readings. Readjust the thermostat to make sure it is square with the wall and re-tighten all attachment screws.

If All Else Fails

If all your adjustments and tests still cannot get you a correct thermometer reading, consider replacing the old mechanical unit with a new digital electronic thermostat with an LED temperature readout. New digital models do not use traditional thermometers and are much more efficient at temperature control as well as displaying an accurate reading.

NOTE: Many power companies offer discount programs replacing old inefficient thermostat with new digital programmable models that through monthly reduction in energy bills will more than pay for the investment in the long run. Also check to see if you can take advantage of any federal, state or local tax savings offered to motivate homeowners to make the switch.