Nest Thermostat Fan Always On: How to Turn it Off!

Using your fan, whether you’re heating or cooling the home, ensures that you have an even temperature throughout because it improves air circulation.

But if your Nest fan runs continuously, even when the heating and cooling options are turned off, this indicates a problem.

It may also potentially create a problem for you because you’ll have a higher electric bill, you’ll overwork your HVAC/forced air system, and you’ll have to replace your air filter sooner and more often.

It’s wise to resolve the problem as soon as you notice it, and you don’t have to be a whizz to figure it out.

Why Won’t My Nest Thermostat Fan Turn Off?

We’ll start by covering the most common reasons that Nest fans can continually run. Understanding the problem will prevent it from happening again and give you a better knowledge of your Nest thermostat.

While your Nest thermostat is heating or cooling your home, the Nest fan or forced air system will automatically come on. This is the default setting for the thermostat unless you change it.

If your Nest fan or forced air system has a separate fan wire in your Nest thermostat’s G connector, this means that you can turn the system fan on even while it’s not in heating or cooling mode.

This also means that your Nest thermostat allows you to set up a fan schedule, control the fan speed and manually turn your fan on or off in the Nest app or on the thermostat itself.

It’s on fan-only mode

This feature gives you the option to set a time range to turn the fan on even if it isn’t in heating or cooling mode. Press the Nest thermostat ring and navigate to the main menu.

Then select the “Fan” option and check if the “Fan-Only” mode is enabled. If it is, pick “Stop Fan,” and it should turn off. If it doesn’t turn off, that might be an indication that it’s set to a fan schedule.

It’s on a fan schedule

The thermostat has a fan timer feature that allows you to set a schedule for the times that the fan is on or off.

Press the Nest thermostat ring and open the main menu. Navigate to “Settings” and go through the menu until you locate “Fan Schedule“. You should see a “Disable” button that allows you to turn off any enabled daily fan schedule.

Also, ensure that your Nest fan isn’t set to the “Always” mode, which will quite literally keep your fan spinning constantly.

How to Change Your Nest Thermostat Fan Settings

This section is about what to do if you want to switch off the fan manually. You’ll also get a good look at your fan settings while going through these steps, and it’s a great idea to get better acquainted with them.

You have to keep an eye out as you scroll through to make sure that there aren’t any settings enabled that might be causing it to still run. This step is necessary because it’s quite a common occurrence that people accidentally toggle settings and don’t realize it.

How to change Nest settings on the Nest Thermostat

Depending on which model Nest thermostat you have, the settings and options will be different, so make sure you know which instructions you need.

Nest Thermostat

Tap your thermostat’s touch bar and choose “Fan“. Choose how long you would like your fan to run and press “Confirm“. Select “Start” to turn the fan on.

The fan will turn off after the time you’ve set it to, but if you want it to stop immediately, select “Stop” in the fan menu.

Nest Learning Thermostat and Thermostat E

First, go to the menu view on your thermostat and navigate to Quick View. Then select “Fan“. After that, you can set a timer for when you want the fan to turn off by turning the ring.

This is also where you can adjust the fan speed if you have a multi-speed fan. If you want to stop the fan immediately, you can pick “Stop Fan“, and it’ll stop. Make sure to check the Nest thermostat display for a spinning fan icon because that means it’s still on.

How to change Nest settings on the Nest app

First, navigate to the Nest app on your device and then select your thermostat. Select “Fan” and put in how long you want it to run for.

This is also where you can adjust the fan speed if you have a multi-speed fan. If you want to make the fan turn off immediately, you can select “Stop” and turn it off.

What to Do If It Still Won’t Turn Off

If you’ve tried to turn the fan off manually, change the settings, or if your thermostat model doesn’t give you fan control options in either your app or on your thermostat, you might want to consider some of the following possibilities next.

*If you aren’t sure whether the problem is with the Nest or your HVAC system, simply re-install your old thermostat and see if the problem persists. If the problem is resolved by using your old thermostat, then the issue must be a result of your wiring or else the Nest thermostat itself.

Faulty Thermostat

There might be something wrong with your thermostat. The Nest sensor might not be able to detect that the room is at the desired temperature, which would trigger the fan to stop running at the appropriate time.

Software Problems

A bug in the software can make the fan spin continuously even after you attempt to turn it off. In this case, it might be beneficial to reset your thermostat.

Resetting the thermostat will undo any settings that may have been accidentally enabled as well as delete the errors by rebooting the system. While this should fix any software problems, there’s no guarantee.

Faulty Wiring

This might have happened during installation; there could be something wrong with the wiring of the Nest thermostat or the fan. Detach the Nest from the wall and see if you can find any broken and disconnected wires.

If you do find some wiring that looks wrong or if you’re unsure, consult your user’s manual for guidance.

Hardware Problems

A continuously running fan can also be a sign of hardware problems, either with the fan or with the Nest thermostat. The easiest and quickest way to ascertain whether or not your fan problem is hardware related is to detach the Nest sensor from the wall.

If the fan keeps spinning after you’ve detached the sensor, then it’s probably a problem with your fan. If the fan stops spinning, the problem is with your Nest thermostat.

If you’ve tried everything or if you’ve determined that it’s a hardware issue, it’s definitely time to call for help. Consult the relevant support team for your HVAC/forced air system or Nest support. You can also consult a technician.


Why does my Nest thermostat’s fan run even when the system is off?

This could be due to a number of factors such as a software glitch, faulty wiring, or an incorrect setting. To determine the cause, check your fan settings, try resetting the thermostat, and examine the wiring. If you’re still having problems, it may be time to consult with a technician.

What is the role of the G wire in my Nest thermostat?

The G wire, or fan wire, is what allows your Nest thermostat to control the HVAC system’s fan independently of the heating and cooling modes. If your system has a G wire, you’ll be able to manually turn your fan on or off, control its speed, and set up a fan schedule.

How do I know if my fan problem is due to faulty wiring?

One way to determine if faulty wiring is causing your fan problem is to disconnect the Nest thermostat. If the fan continues to run, then the issue is likely with the fan. If the fan stops, the issue might be with the thermostat’s wiring.

Can software problems cause my Nest thermostat’s fan to run continuously?

Yes, a bug in the software can cause the fan to run continuously. Resetting the thermostat can often fix software problems.

What should I do if resetting my Nest thermostat does not solve the problem of the fan running continuously?

If resetting your Nest thermostat doesn’t solve the issue, it might be time to seek professional help. You can consult with the support team of your HVAC/forced air system or Nest support, or you can hire a technician.

How do I reset my thermostat?

Navigate to “Settings” on your thermostat, then find and select “Factory Reset“. You’ll be prompted to confirm your choice, and after you do, it should reset itself.

How long should I run my Nest fan?

This is totally up to you and dependent on your temperature needs and preferences but bear in mind all the cons laid out at the beginning of the guide.

How to Regularly Maintain Your Nest Thermostat and HVAC System

One way to avoid running into issues with your Nest thermostat or your HVAC system’s fan is to perform regular maintenance checks. This will not only help you avoid problems but also extend the life of your equipment.

Once a month, check the Nest’s batteries. Most models will alert you when the batteries are low, but it’s a good idea to check them manually as well.

Remember to replace your HVAC system’s air filter at least once every three months, or more often if you have pets or allergy sufferers in your home. A clogged filter can affect the performance of your system and may even cause the fan to run continuously.

Also, keep the area around your HVAC system and thermostat clear. Dust and debris can interfere with their operation, and heat sources near your thermostat can affect its temperature reading.

Lastly, consider having your HVAC system inspected by a professional at least once a year. They can spot and fix potential issues before they turn into major problems.

For more troubleshooting tips on Nest thermostats, see:

Final Thoughts

Usually, when your fan keeps running, there are a variety of reasons why and so it’s best to investigate and troubleshoot thoroughly. You’ll want to ensure that it’s something you can’t fix yourself before you pay someone to do it for you.

Generally, it’s fairly simple to resolve the issues that may be causing your fan to work improperly.