Nest Thermostat Not Cooling | Let’s Fix It

Are you using a Nest thermostat in your home, which does not effectively cool your home?

A variety of reasons could cause this, and there are several reasons why the device might not be cooling, or worse, that it is blowing hot air when it should be blowing cold air.

Regardless of the solution, it would be best if you began by troubleshooting the problem. A rewiring is usually required to fix the problem.

Troubleshooting Nest Thermostat Not Cooling

The incorrect labeling of your wiring is causing it, so the Nest thermostat does not cool because it is hooked up to your old thermostat’s “Conventional” side instead of the “Heat Pump” side.

You should redo the wiring from your old thermostat setup using the heat pump side and rewire your Nest accordingly to avoid this scenario.

Thermostat Not Cooling

Mislabeling of thermostat wires

The next time you have a hunch, you might be misidentifying your cooling system and, as a result, mislabeling your wires. Read through this article.

Precisely Analyze Your Home Cooling System

First and foremost, you need to determine what type of cooling system you have in your house. This can easily be done by checking your external system, as this is the easiest method.

An air conditioner should be marked with a label to determine whether it is an air conditioner, a heat pump, etc.

Alternately, if you want to obtain more information about the device, the brand name plus the model number can be found on the device and Googled to get more information about it.

If the outside system appears to be engaged, another great investigative tip is to turn on the heat in your house and see if the outside system kicks in as well. Then it is confirmation that you are indeed using a heat pump if it does show up on the screen.

Since you’re experiencing Nest Thermostat cooling problems, it’s possible that you have a heat pump system but had thought you had a conventional one.

Relabeled Thermostat Wiring

You’ll likely need to relabel the thermostat wires from their original configuration now that you know what kind of cooling system you have.

It would be beneficial if you had a picture of the wiring setup on your old thermostat to refer to during the process.

Using that photo, all you have to do is relabel the wires with the Heat Pump row.

After appropriately labeling your wires, you can use Google’s free Nest compatibility checker to confirm your wires are compatible.

To set up your Nest device, you will need to use the compatibility checker, which automatically generates the correct Nest thermostat wiring for your specific device.

The Nest thermostat needs to be rewired

Whenever you are rewiring your Nest thermostat, please ensure no power goes to the device before starting. So you can safely work on the wiring, a circuit breaker should be turned off for that room.

Take off the display from your Nest thermostat, look at the diagram generated by the compatibility checker, and begin disconnecting and reconnecting the needed wires based on the results.

To ensure that all the Nest Thermostat wires are securely connected to the right places, it is important that you double confirm that they are not kinked.

After replacing the Nest Thermostat display screen, turn back on the circuit breaker, and the product should be working as it should.

Once your Nest has booted back up, you should notice that your cooling issue has been resolved.

NOTE: Do you know What Is the Best Way to Connect a Nest Thermostat to a Phone?

A circuit breaker tripped

You can check your circuit breaker box to see if any breakers have tripped or if you still have problems with cooling. It is very easy to check to see if any switches are in the off position.

Once you have done this, you flip the breaker on, then off, and then back to the on position. By doing so, the breaker should be reset, and you should be able to fix the problem.

circuit breaker tripped Nest thermostat

Wiring issue in RC, RH

Older thermostats are sometimes equipped with a single R wire, bridged using a piece of metal to the RC or RH wire. These wires can be easily overlooked.

However, the Nest thermostat separates the RC and RH wires into their ports to be used separately. You should connect one red wire to the RH port on Nest if you only have one red wire.

RC, RH Wiring Issue Nest Thermostat

However, if this does not resolve your issue, try connecting the red wire to the RC port instead and see if that resolves the issue.

Blowing a fuse inside the air handler

Having a blown fuse within your air handler can also cause your Nest thermostat cooling to stop working. Getting to this fuse can be a little tricky and may require the removal of many screws to remove the air handler cover.

You will be able to see a circuit with a handful of fuses once you have gotten inside.

Blowing a fuse inside the air handler Nest thermostat

Since they’re relatively inexpensive, replacing all the fuses is easy if you don’t know which one is blown.

Troubleshooting: Additional Tips

There is still a chance you will have cooling issues if you have made it this far, but you can try. Here are some last fixes.

Make sure your cooling system is compatible with Nest

If your cooling system is not compatible with the Nest thermostat, there is always a possibility that it is not compatible. It is important to note that the Nest is incompatible with high voltage or solid fuel systems.

Depending on what it uses, you may not be able to use the Nest effectively with your home’s cooling system.

It should make determining this fairly simple for you to conclude based on your already done work.

Reboots the system

Resetting your Nest thermostat may not resolve an issue as serious as your thermostat not cooling, but it is still worth giving it a shot.

You can accomplish this by cutting the power to the Nest thermostat in another way or by turning off the fuse – you need to make sure it’s completely shut down.

It is recommended that you wait five minutes after turning the  Nest thermostat back on before turning it back on.

Wait a few minutes while the device reboots, and then once the Nest thermostat reconnects with the systems in your home, you should wait a little longer.

It is also possible to apply a manual reset directly to your device:

  • You can open the Quick View menu by pressing the thermostat ring.
  • Choose the settings that suit your needs.
  • Press and hold the ring until it reaches the Reset position.

Thermostat Reinstallation

You will want to ensure that the Nest thermostat is actually causing the problem if you have made it to this point and are still experiencing cooling issues. You could do this by reinstalling the old thermostat, which is one way.

As with the last time, you will have to start by switching off the fuse for the  Nest thermostat before touching any wiring.

You can check whether anything is wrong with the wiring in your home by installing your old thermostat.

For instance, if the old thermostat worked perfectly, but the  Nest thermostat didn’t, the Nest isn’t working properly.

It is more likely that the wiring for your cooling system is malfunctioning if the old thermostat isn’t working either. The electrical system likely needs to be inspected by a professional electrician.


You might want to contact a professional if you’re still experiencing cooling issues after attempting all the above.

Having a professional check out your wiring will allow them to detect all of the problems you may not see in yours. Furthermore, they can complete their work in the safest manner possible.


Want to Read more?

Are Bose Earbuds Waterproof? | Complete Guide

Leave a Reply

Your email address will not be published. Required fields are marked *