An uncalibrated thermostat can cause your HVAC system to work harder than necessary, leading to high energy consumption and more-than-usual wear and tear. If energy bills start increasing without any corresponding change to outdoor temperatures or utility pricing, your thermostat may be due for calibration.
The Room Temperature and Setting Don't Match
If, no matter how often you set the thermostat, the setting and room temperature never match, the unit has likely lost accuracy. The cause may be a calibration issue. Or, the unit may have a wiring problem affecting its function and power supply.
If both your thermometer and your thermostat display the same temperature reading, the thermostat's accuracy and efficiency are good. A difference of 3 degrees or less is generally nothing to worry about. If the readings are different, there is likely an issue affecting your thermostat's function.
Thermostat acts as the brain for your HVAC system and regulates your home temperature, so it's important to ensure that it is properly calibrated. If the thermostat isn't adjusted, it won't be able to read your home temperature correctly, and your HVAC unit will never achieve your desired temperature.
They must also be calibrated after an extreme temperature change (e.g., after measuring a hot food first and then a frozen food, or after a thermometer is dropped). All calibrated thermometers should be accurate within 2 degrees (plus or minus 2 degrees).
Incorrect temperature readings can lead to undercooked food, increasing the risk of foodborne illnesses. Regular calibration of your food thermometer is the best way to maintain its accuracy. It helps you avoid the pitfalls of undercooking or overcooking, ensuring your meals are both delicious and safe.
If your thermostat is not reading correctly, it might be due to a dirty or faulty sensor. A quick fix could be to gently clean the sensor with canned air to remove any dust buildup. However, if problems persist, replacing the thermostat could be the next step.
Easy Maintenance: Tighten the Calibration Screw
It's located inside a curled piece of metal inside the thermostat. Using an appropriately sized screwdriver, turn the calibration screw to open the contacts. Wait a few seconds, then turn the screw to close the contacts.
If the temperature is set to 74°F but the thermometer shows 78°F, you will have to recalibrate the thermostat to account for this 4-degree deviation. Even with older AC units or furnaces, you might have to recalibrate your thermostat from time to time.
The Vicks Non-Contact Infrared Body Thermometer provides accurate and color-coded results in just two seconds or less. It is easy to operate, gets the job done quickly, and can be used on the body or liquids, which is why it is our top choice.
A bad thermostat can be detected when your AC or furnace is not turning on, your HVAC systems are not turning off, the thermostat not responding, your HVAC system is short-cycling, the room temperature not matching the temperature displayed on the thermostat, and the programmed setting resetting themselves.
Checking the calibration of your thermostat is easy and should be done once a year, generally in the fall. To do so, locate your home's thermostat and tape an accurate thermometer on the wall next to it. Wait 15 minutes and check the temperature reading on both devices.
Turn on the heat on the thermostat and increase the temperature. You should hear a sound from both the thermostat and the furnace, and whichever doesn't make a sound has a problem.
Get an Indoor Thermometer
Another way to test your thermostat is to use a thermometer. Place the thermometer in the room and turn on the AC. After a few minutes, check the thermometer to see what temperature it's reading. The temperature should be lower than when you started.
Using a small screwdriver, gently turn the calibration screw or move the adjustment lever until the thermostat's temperature reading matches the thermometer's reading. Make minor adjustments and allow time for the thermostat to adjust to the new setting before rechecking the temperature.
Dirty or worn flame sensors, blower motor problems, clogs in the condensate lines, and electrical issues are some of the many problems that can leave your HVAC system failing to deliver the temperatures you've programmed in your thermostat.
Clean the Thermostat
Sometimes, when the room temperature doesn't match the thermostat setting, the problem could be dirt buildup on its interior parts. A dirt coating around the inner components may create excess heat and cause the thermostat to give the wrong readings.
Locating the Reset Button
Remove the thermostat cover by either snapping it off or unscrewing it, depending on the model. Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it.
If your thermostat is set to a temperature regulation mode or has an energy-saving program enabled, it might reset to conserve energy.
There are two main types of thermometers. The dial or bi-metallic stem thermometer and the digital or instant read thermometer. The bi-metallic stem thermometer is a mechanical thermometer which must be calibrated regularly. A digital or instant read thermometer is electronic and cannot normally be calibrated.