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Why Nest Thermostat Showing Wrong Temperature? – Troubleshooting Guide

Nest thermostats offer the highest convenience. Not only do they learn what temperatures you like, but they also spare you from manually adjusting your air conditioning unit all the time. But like all electrical appliances in your home, Nest thermostats are susceptible to issues, such as displaying the wrong temperature.

Nest thermostats show the wrong temperature when still learning your preferences when placed in cold or hot spots, when the room takes longer to warm up, and when in the maintenance band. Solutions include mounting the thermostat in the right place and giving it time to learn your preferences.

In this article, we’ll explore some issues that make your Nest thermostat show the wrong temperature and how to fix them.

1. Nest Thermostat Is Still Learning Your Preferences

One of Nest thermostats’ coolest features is learning what temperatures you like at different times of the day and adjusting the AC unit automatically. Essentially, the Nest thermostat is a temperature sensor that reads the room temperature and automatically creates a schedule based on your patterns.

The process takes a couple of days, during which your thermostat may not display the room’s actual temperature. However, you can still set up a temperature schedule manually and adjust it at any time.

As your thermostat learns what temperatures you like, there could be slight differences between what temperature displays on your thermostat and what the actual temperature is. This difference could also occur when you change the temperature frequently or when you reinstall your thermostat.

How To Fix?

As your thermostat learns your preferred temperature, the best thing you can do is wait for a couple of days (2-3 days is enough). Also, ensure that the thermostat has been installed in the right place, somewhere in the middle of a frequently used room. 

If that does not work, you can reset the thermostat in the following steps:

  1. Open the Quick View menu
  2. Go to Settings
  3. Turn the thermostat ring and adjust it to Reset
  4. Select All Settings to completely reset your thermostat

You can also select other options (Schedule, Away, and Network) if you wish to retain specific information. For instance, the Schedule option erases all your set points. The Network option deletes all the network information from your thermostat.

Please note that resetting your thermostat may result in losing additional information, including your temperature schedule.

You may also like: Why Air Conditioning Unit Won’t Turn On? 3 Troubleshooting Steps

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2. Nest Thermostat Is Placed in a Cold/Hot Spot

Your Nest thermostat’s location is critical to its optimal performance. For instance, when you place your thermostat in direct sunlight or near a hot furnace or running electrical appliances, you’re likely to get the wrong reading. Such zones do not represent the actual temperature of the room.

When the thermostat gets the wrong reading, so does the heating and cooling system. What follows is a ripple effect of undesired outcomes, such as discomfort and higher energy bills.

How To Fix?

Mounting your thermostat in a suitable location ensures that your unit captures the right temperature. But what is the right location? First, avoid placing your Nest thermostat near a window. This should help prevent direct contact with sunlight and cold drafts.

Secondly, avoid placing your thermostat near other electrical devices. Electrical appliances emit a significant amount of heat when left to run too long. This feeds a nearby thermostat with inaccurate temperature data. Also, avoid mounting your Nest thermostat on metal surfaces since they gain and lose heat fast.

3. Deadband/Maintenance Band/Temperature Swing

Deadband, maintenance band, or temperature swing is an important feature of the Nest thermostat, which helps to conserve energy when the heating or cooling system is switched on. Essentially, a Deadband is a certain temperature range in which the thermostat will not activate the heating and cooling system. 

It’s a smart way to conserve energy, as the heating or cooling system won’t constantly turn on and off when the temperature is around the set point. This feature is helpful when there’s a huge margin between hot and cold temperatures in the same building on the same day.

The maintenance band on the Nest thermostats allows the temperature to fluctuate by a few degrees before the heating and cooling elements kick in. It also spares the heating and cooling system from premature wear and tear.

How To Fix?

Unfortunately, there is no way to readjust the Nest thermostat Deadband. Nest thermostats usually have a temperature swing of about 1-2°F. Bigger variations above 2°F could make your house uncomfortable, but the good news is that you can have greater control with ThermoTweak, a cloud-based temperature swing limiter application.

ThermoTweak enables homeowners to maintain a temperature swing of 1°, which keeps your home closer to the desired temperature. All you have to do is sign up and activate your thermostat. However, do not mess with the differential, which could affect the shelf life of the heating and cooling system’s components.

4. The System Stays on for a While After Being Turned Off

Sometimes, your Nest thermostat isn’t the problem – it’s the AC system. If you’re like most homeowners, you’ve probably noticed that your heating and cooling system stays on for a while after you turn it off. This is normal, but it can be annoying. So, what other reasons make this happen?

  • A faulty electronic control board
  • Faulty thermostat
  • Faulty thermistor

The electronic control board communicates with various air conditioning unit components, including the fans, motor, compressor, and heater. Essentially, the electronic control board tells the AC unit when to turn on or off in response to temperature changes.

The thermistor and thermostat work together to detect temperature changes and relay the information to the electronic control board. If any of these components are faulty, you could see the temperature difference between, increased run time, and danger to your AC unit.

How To Fix?

One of the simplest ways to fix this problem is to run your thermostat on auto. If that doesn’t solve the problem, check your unit manually.

  1. Open your air conditioner and check for the thermostat, thermistor, and control board condition.
  2. Pay attention to loose wires, disconnected components, and jammed relay switches.
  3. Scan for burnt elements or charred marks on the control board.
  4. For a more comprehensive check, you will need to test for continuity on each component with a multimeter.
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Take note of your AC unit. If it’s undersized for the room, you may need to swap it with a bigger, more powerful unit.

5. Nest Thermostat Shows a Rounded Temperature

Your Nest thermostat shows a temperature that has been rounded off to the nearest 1°F (0.5°C). But in the real sense, the thermostat uses unrounded temperature to call the heating and cooling components. As such, the temperature reading on your thermostat or Nest app may appear different from the actual temperature.

How To Fix?

You can see the unrounded temperature in your Nest thermostat’s technical information.

  1. Go to Settings
  2. Select Technical Info
  3. Select Sensors

Although Nest thermostats display accurate temperatures, there is no other way to disable the rounded temperature. You can only view this information from the technical settings.

Conclusion

If you’re having trouble with your Nest thermostat showing the wrong temperature, don’t worry. First, try restarting your thermostat and if that doesn’t work, reset the device, as this will clear any settings and schedules and require a fresh reinstall. Finally, if nothing seems to work, get in touch with a professional AC repair company to get your unit fixed.