Nest thermostat not cooling: causes and solutions 

In the modern world, more and more companies are trying to create a device that will make your life in the house much more comfortable and favorable by controlling the temperature and even the humidity of the room. One of these devices is the Nest thermostat, which can show the temperature and create a hot or cold airflow.

However, for people who live in hot climates and like to use a cooling system, the “Nest Thermostat not cooling” issue can be a tragedy. If this problem is relevant to you, then this article will help you, as we will discuss the causes of this problem and possible solutions.

nest thermostat

What is a thermostat and HVAC system? 

The Nest thermostat is a device you can connect to through the nest app on your smart device and have complete control over the instruments that change the temperature and humidity inside your home.

Moreover, the thermostat itself can show you exactly what changes have occurred, for example, a decrease in temperature from an open window, and so on.

What the thermostat connects to is called the HVAC system. HVAC stands for heating, ventilation and air conditioning system. That is it is a set of devices, for example, a heat pump system and air conditioner, which affects the atmosphere throughout the house.

The Nest Thermostat and the HVAC system are connected by a wired system and if there is a problem in the HVAC system, then this problem will also go to the thermostat.

What is a cooling system in Nest thermostats? 

A cooling system is a system by which the Nest thermostat can reduce the temperature inside the room by creating cold air.

Most often, this thermostat is assisted by devices such as an air conditioner and all you need to turn on the cooling system is to use your phone or the thermostat screen to select the temperature you need.

Nest thermostat not cooling: causes and solutions 

Why is my Nest thermostat not cooling? 

To successfully solve the problem with a non-working cooling system, you must first understand why exactly this problem occurred in the Nest Thermostat.


The first thing that could cause this problem is an internet connection problem inside the Nest device.

If the Nest display screen does not have an internet connection, you will not be able to control the temperature, that is, the cooling system, from your phone.


Perhaps because the thermostat was trying to reach the target temperature, the thermostat system could overheat and the battery inside could drain quickly.

Such a problem may arise due to a broken system for constantly recharging the device from the HVAC system or a broken c-wire.


In particular, the problem with sensors occurs on the old thermostat, since the sensor system can wear out over time and without proper diagnostics.

Sensors are responsible for connecting your thermostat to other devices that change the temperature and they also recognize when the temperature has gone beyond the desired climate in the room. If the sensors are broken, then the heat pump or conditioner cannot be activated.

Nest thermostat not cooling: causes and solutions 

Wiring system

Also, it is very important to check if there is a problem inside the wiring system inside the thermostat itself and internally connecting it to the power supply, since the wires are very fragile.

Very often, it is the old thermostat that has a large number of exposed and worn wires.

A problem with common wire or regular wire can lead to malfunctioning of the thermostat and lack of power to control the cooling of the device.


Auto-schedule is a feature that allows you not to worry about temperature changes even when you sleep, but if you have a problem with the auto schedule, it will be difficult to activate room cooling.

The thermostat works according to the schedule and if there is a problem with the schedule, this can lead to a breakdown in the entire system.


An incompatible system is a huge problem especially if you just swapped out an old thermostat for a new one and didn’t check if the thermostat parts fit your HVAC system.

In the case of incompatibility, some functions, such as a moisture test, may work, but there will be no connection to individual devices, such as a cooling conditioner or heat pump.

Nest thermostat not cooling: causes and solutions 

How do I fix my Nest thermostat not cooling? 

After we have discussed exactly the causes of the “Nest thermostat not cooling” issue, it is worth understanding what methods can be used to solve this problem.

Cooling system

The first thing you can do is confirm thermostat cooling system. You need to specifically check if the Nest thermostat is properly wired to the cooling system.

In case you have an old thermostat, then you need to refer to the user manual to understand how to correctly confirm the cooling device.


A mandatory item is to check the Nest thermostat wiring system. To do this, you must first remove the Nest thermostat screen.

Now you need to check the wiring inside, see if all the wires are connected correctly and if any bare wires need to be replaced. Then plug the thermostat back in and turn it on.


There may be a problem with the common wire connection to your Nest Thermostat.

In this case, you need to first turn off the thermostat, then get to the thermostat wiring section and find the c-wire wire and then disconnect it. Reboot the device and check if the cooling system has improved without the c wire.

Circuit breaker box

Also, often problems in the thermostat can be associated with the circuit breakers box, namely the problem with the switch inside the breaker box.

You need to open the circuit breaker box and pay attention to the lever that is responsible for activating the Nest Thermostat and HVAC systems and if it is off, switch it to ON mode or try turning it off and on.

Nest thermostat not cooling: causes and solutions 

Auto schedule option

As we said earlier, the problem may lie within the scheduling system of your thermostat, to check this, you must first open the thermostat application on your phone.

After that you will see the “ECO temperature” button, you must turn it off and also turn off the Auto schedule. Now check if the blowing cold air system is working.

RC or RH wiring

This problem is more relevant for the new Nest Thermostat models than for the old thermostat. Try turning off RC and RH in your thermostat’s wiring compartment, then start it.

If the cooling system did not work or the thermostat itself stopped working, then reconnect the RC and RH and check if the problems are fixed.

Blown fuse

HVAC blown fuse box can become not only a problem with the operation of the cooling system but also completely ruin the charging system of the thermostat itself.

You need to check if there is a blown fuse inside the HVAC system and if you notice them, it is better to replace them immediately or consult the user manual for help.

In-compatible nest

Another option is to replace your heating and cooling units if they don’t fit your thermostat. In the event of a problem with the connection of the thermostat to the system, temperature control will not be possible.

You can refer to the user manual or try to find which devices are suitable for your thermostat to immediately purchase the right one.

Software update

Although this cause seems unlikely, an outdated software update on your Nest Thermostat can indeed lead to a huge number of problems, such as the inability to connect to the cooling system.

To fix this you need to go to the settings either on your phone or on the device itself and start the update process.

Y1 Terminal connection

The last method to solve this problem is to disconnect the wire in the Y1 wiring section that is responsible for cooling and connect it back.

Factory reset of your Nest thermostat 

A good way to solve any problem, even with the cooling system, inside the Nest Thermostat is to factory reset, but the main thing is to follow the instructions to do everything right and not damage the system inside.

First, you need to activate your phone, which should have the Nest app installed.

You need to select the thermostat you want to reset, after which you can select the settings option, you need to go into it and if you scroll down you will notice a factory reset menu that you need to click on.

Nest thermostat not cooling: causes and solutions 


Why does my Nest thermostat say in 2+ hours to cool?

If you receive such a message, it means that your Nest Thermostat needs more time to fully understand the information about the device for reducing the temperature and scheduling/duration of work. 
It is better to wait until this process is over to calmly enjoy the cooling of the room because if you suddenly stop the process, you can damage the operation of the device.

Why is my Nest not turning on my AC?

The reason that your AC does not turn on and, as a result, a cooling issue occurs, most often is either a problem with connecting to Wifi or a problem with charging the thermostat itself, since when the charge is low, the device cannot perform its work properly.

How do you force Nest to cool? 

You can make your thermostat cool. To do this, you also need to open the Nest app on your phone, and then select your thermostat, which should already be in cooling mode.
You need to hold down the temperature button, after which the count will appear, which you need to set on your thermostat. The main thing here is to do everything carefully and try not to press other buttons, so as not to damage and create an obstacle to the operation of the thermostat, as well as improve the connection between the device and the cooling instrument. 


We hope that after reading this article “Nest Thermostat not cooling” will no longer be an actual problem for you. Moreover, now you know all the causes of the problem between the Nest Thermostat and cooling system and understand what are the methods for solving these problems under different circumstances, and different tools.

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