How To Change Nest Smart Thermostat To Air Conditioning

To change your Nest thermostat to air conditioning, simply switch the device's mode to Cool. The exact steps depend on your Nest model, but the process is quick and can be done directly on the thermostat or remotely via the Google Home or Nest app.

Understanding your Nest thermostat modes

Before making the switch, it helps to know what each mode does so you select the right one for your needs. Your Nest thermostat offers four main modes:

• Cool, The system runs your air conditioner to lower the temperature to your set point. This is the mode you want for summer.
• Heat, The system runs your furnace or heat pump to raise the temperature. Use this in winter.
• Off, The HVAC system is completely turned off. No heating or cooling will occur, though the thermostat itself stays powered.
• Heat•Cool, This is an automatic mode where you set both a minimum and maximum temperature. The Nest will switch between heating and cooling as needed to keep the temperature within that range. It’s ideal for unpredictable weather or when you want the system to handle both functions without manual changes.

For most users, switching to air conditioning simply means selecting Cool. If you want the Nest to handle both heating and cooling automatically, choose Heat•Cool instead.

Change to cool mode on a Nest Learning Thermostat (3rd gen or E)

If you own a Nest Learning Thermostat (3rd gen) or the Nest Thermostat E, follow these steps to switch to cool mode using the physical ring:

1. Press the thermostat ring to open the Quick View menu.
2. Turn the ring to highlight Mode and press the ring to select it.
3. Turn the ring again to highlight Cool.
4. Press the ring to confirm your selection. The display will show the cooling icon (a snowflake) to confirm the change.

That’s it, your Nest is now in air conditioning mode. You can adjust the temperature by turning the ring up or down.

Change to cool mode on a Nest Learning Thermostat (4th gen)

The 4th gen Nest Learning Thermostat has a slightly different interface. Here’s how to switch it to cool mode:

1. Press the thermostat toward the wall to open the main menu.
2. Turn the dial to highlight Mode and press the dial to select it.
3. Turn the dial again to highlight Cool.
4. Press the dial to confirm. The snowflake icon will appear on the display.

Once you’ve done this, your 4th gen Nest will begin cooling your home to the temperature you set.

Change to cool mode on a Nest Thermostat with touch bar

The Nest Thermostat (the non-Learning model with a touch bar on the right side) uses a different control method. Here’s how to switch it:

1. Tap the touch bar to wake up the display and open the menu.
2. Slide your finger up or down on the touch bar to highlight Temperature mode.
3. Tap the touch bar to select it.
4. Slide your finger to highlight Cool.
5. Tap the touch bar to set it. The snowflake icon will appear on the screen.

This model is often sold as the “Nest Thermostat” without the “Learning” label, so if you have that one, these are the steps you need.

Change to cool mode using the Google Home or Nest app

If you prefer to change the mode remotely, or you’re not near the thermostat, use the app. The steps differ slightly depending on which app you have.

Using the Google Home app (all Nest models)

1. Open the Google Home app on your phone or tablet.
2. Tap Favorites or Devices at the bottom of the screen.
3. Select Climate from the list of device types.
4. Choose your Nest thermostat from the list.
5. Tap the Temperature mode icon (this icon changes based on the current mode, it might show a flame, a snowflake, or a circle with a slash).
6. Select Cool from the options that appear.

The change is sent to your thermostat instantly via Wi-Fi.

Using the Nest app (for Nest Thermostat E and Nest Learning Thermostat)

1. Open the Nest app on your phone or tablet.
2. On the home screen, select your thermostat from the list of devices.
3. Tap Mode, this is usually shown near the bottom of the thermostat’s detail screen.
4. Choose Cool from the pop-up menu.

Both apps will confirm the change, and your thermostat will switch to air conditioning mode immediately.

Testing your air conditioning and troubleshooting

After switching to Cool mode, you should verify that your air conditioning system actually turns on and cools properly. Here’s how to test it and what to do if something isn’t working.

1. Set the temperature below the current room temperature. On your thermostat, lower the set point by at least 5 degrees. This forces the system to call for cooling.
2. Wait a few minutes. The AC may take a couple of minutes to start, especially if it has a built-in delay to protect the compressor.
3. Check the vents. Hold your hand over a supply vent. You should feel cold air blowing out within 5-10 minutes.
4. Listen for the outdoor unit. If you have a central AC, the condenser unit outside should be running (fan spinning, compressor humming).
5. Monitor the temperature.

If the AC doesn’t turn on or blows warm air, try these troubleshooting steps:

• Check the mode again. Make sure the thermostat is still set to Cool and not Off or Heat.
• Check the set temperature. It must be lower than the current room temperature for cooling to activate.
• Inspect the air filter. A dirty filter can restrict airflow and cause the system to overheat or freeze. Replace it if it’s clogged.
• Verify the circuit breaker. Ensure the breaker for your AC unit is in the “On” position. Sometimes a tripped breaker can go unnoticed.
• Check for error codes. The Nest display may show a warning or error code. Refer to the Google Home app or Nest support for what the code means.
• Restart the thermostat. If you suspect a glitch, you can reset a smart thermostat by going to Settings > Reset > Restart on the device. This won’t erase your settings but will reboot the system.
• Check the C wire. If your system isn’t getting power, you may need a common wire (C wire). While Nest thermostats often work without one, some systems, especially zoned ones, require it. If you’re unsure, consult a professional.

If none of these steps resolve the issue, your HVAC system itself may have a problem (like a refrigerant leak or a faulty capacitor). In that case, contact a licensed HVAC technician. Nest thermostats are designed to work with most 24V systems, but if you have a high-voltage system, a professional may need to install a step-down transformer to make it compatible.

Once your AC is blowing cold air and the temperature is dropping, your Nest thermostat is successfully switched to air conditioning mode. Enjoy the cool comfort!

For the wider topic, see reset a smart thermostat.