how to calibrate nest thermostat

Knowing how to calibrate Nest thermostat is essential if you want comfort in your home.

If your thermostat has calibration issues, you may need to check several things to restore it to normal working.

See below several steps you can use to calibrate your Nest thermostat.

To calibrate Nest thermostat, restart it. Press its ring until the screen becomes black. Allow it a few seconds to back up and start running. Read the temperature to see if it is correct when compared to an indoor thermostat reading.

What is Thermostat Calibration?

Thermostat calibration is the art of your thermostat initiating a cycle after sensing your room’s temperature.

The sensor can then decide if your room needs heating or cooling at a particular time of the day.

If the calibration is proper, the thermostat should read your room’s temperature correctly as it is, using an indoor thermometer.

Why is Nest Thermostat Calibration Important?

When you calibrate your thermostat once in a while, these are some of the benefits you will have.

1. Comfort                

You can be sure that during the hot weather, you will have the cool breeze you need.

Also, during cold weather, you will not suffer from cold because you will have the necessary warmth from your HVAC system.

2. It Prevents the Thermostat from Malfunctioning

If the thermostat does not read correctly, it may cause it to malfunction. Hence, calibration will improve its accuracy and efficiency.

3. You Will Save Energy

When your thermostat has improper calibration, you will need to adjust your temperature settings more often.

Of course, after frequently adjusting your thermostat, you will not expect anything less than a higher electricity bill.

What Causes an Improper Calibration in a Nest Thermostat?

If your Nest thermostat has calibration issues, it may be due to any of the following reasons.

  • Dust build-up
  • Loss of power
  • You bumped the thermostat

You will notice that your Nest thermostat has improper calibration when it has poor temperature control.

Also, the AC will have erratic behaviors like having too few or too many cooling cycles.

When you note these signs in your Nest thermostat, kindly call an HVAC expert to calibrate it.

How to Calibrate Nest Thermostat – Complete Steps

calibrate nest thermostat

Below are several steps you can use to calibrate a Nest thermostat if you love handy work.

Remember to incorporate an expert when you are not sure about any action.

Step #1: Check the Nest Thermostat Accuracy

To know that your thermostat is well calibrated, you first need to check if its reading is accurate.

To confirm that, use a thermometer. Tape it next to the thermostat and read your room’s temperature.

Wait for around a quarter an hour, then read the temperature of your room on both the thermometer and the thermostat.

Your thermostat is accurately calibrated if the reading is the same or has a variance of 10 F and below.

If the variation is more than 1 degree Fahrenheit, your thermostat will need calibration.

Kindly have an expert adjust your thermostat to get it reading the correct indoor temperature.

Also, it is crucial to practice calibration at least every month during the fall to ensure that your thermostat is always reading correctly. Besides, it helps you maintain your thermostat’s efficiency.

If you tested the temperature difference because you felt something else was incorrect, it would be wise to have an HVAC pro tune the thermostat for you.

Step #2: Restart the Thermostat

The simplest way to calibrate a Nest thermostat is to restart it. Press the thermostat’s ring until the screen becomes black. Give it some time to back up and run.

After restarting, the temperature value should be correct. Compare the readings with your thermometer. If the difference is still significant, go to the next step.

Step #3: Clean Inside the Thermostat Gently

Once you find a difference in the temperature readings, or a big variation, go on to clean the thermostat’s inside.

Remove the cover, then clean each part gently.

When cleaning, do not use rough components. Go for soft brushes or a soft piece of fabric.

You can also opt for a one-dollar bill, which is very soft, a bit abrasive, but thin. Hence, it is an excellent piece to clean inside the magnetic connections.

Do not go for a vacuum cleaner when cleaning your thermostat. The suction is quite hard and may be too strong for delicate parts like the coils.

In the case that you use a vacuum cleaner and a part of the thermostat breaks, do not suck it into the vacuum’s reservoir.

Step #4: Unbend the Mercury Vial

If your Nest thermostat has a mercury vial, it might be bent, causing your thermostat to have calibration issues.

Confirm that the mercury vial is straight using an eyeball. If it is bent, use a level to straighten it.

Do not attempt to use your fingers or any part of your body to level the mercury vial. Remember, mercury should not come into contact with your skin.

Also, you can consider calling a professional if you find it difficult to level the mercury.

Step #5: Adjust the Thermostats Calibration Screw

Your Nest thermostat might lack a mercury vial but will have a calibration screw. Adjusting this screw can also calibrate your thermostat.

Locate the calibration screw inside a curled metal in the thermostat. Find the size of the screw, then look for the right sized screwdriver to turn it back and forth.

Turn until the contacts open, then wait a few minutes to screw and close the contacts.

This opening and closing practice resets the contacts. Hence, if there was any lousy setting causing the thermostat not to calibrate, it fixes it.

Step #6: Check the Wiring

Have you adjusted the calibrating screw, but your thermostat is still having calibration issues?

Here is another way to try out.

Uncover your thermostat and check if all wires are secure and correctly inserted. Check if the wires are corroded with rust or have any dirt. 

Corrosion and dirt are a big issue to most thermostats and can reduce their efficiency.

So, remove the dirt or corrosion using a cotton swab. Confirm if the calibration is okay before closing the thermostat.

Step #7: Check the Temperature Again

Are you done with the above troubleshooting steps? To check if your thermostat is now in order, use a thermometer again to check the room temperature.

See if there is a difference between the readings on the thermostat and thermometer.

Remember not to read the temperature before 15 minutes are over to allow the thermostat time to calibrate.

If you still see a difference in the readings, your thermostat has a bigger issue. Hence, you will need an expert’s hand in it to try troubleshooting it for you.

Use a thermometer alongside your thermostat to read your room’s temperature. Check if the reading is the same on both devices. If not, restart your thermostat and check if the temperature will come back to normal.

If not, check the thermostat’s wiring to remove dirt and corrosion to fix the calibration issues.

Read Next: How to Set Nest Thermostat to Hold Temperature?


Understanding how to calibrate Nest thermostat will help you increase its efficiency.

Practice calibration every month even if you sense nothing wrong with your system.

The above steps are convenient and will help you when you are ready for the practice.

Nicole B