Nest Thermostat Flashing Color Guide – Red, Blue, Green, Orange, Yellow

By Trae Jacobs,

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The Nest thermostat is a must-have smart device for your home. The Nest Thermostat regulates the temperature to keep your indoor space comfortable and monitors your energy usage. The best part is that it communicates vital information to you that is easily manageable.

To maximize the usefulness of your Nest thermostat, you need to understand what it is telling you. The various face colors have different meanings, and here are the important ones you need to know.

What Each Color Means

The Nest thermostat gives you complete climate control for your indoor space. This smart device will tell you all sorts of information about your home. The Nest Thermostat will:

Display the current temperature.
Record your energy consumption.
Help you make energy-conscious decisions whether you are heating or cooling your home.

Each color the Nest thermostat face displays tells you something different. These colors and messages vary according to your Nest thermostat product type.

Color	Products	Reason
Red	Nest Thermostats	Low battery.
Blue	Heat Link for Nest Thermostat E, 3rd Gen Nest Learning Thermostat	The thermostat is connecting to the Nest app or a software update.
Green	Heat Link for Nest Thermostat E, 3rd Gen Nest Learning Thermostat, 2nd Gen Nest Learning Thermostat	The heat is on.
Green	Nest Thermostats	Software update.
Orange	Nest Thermostats	Low battery.
Yellow	Heat Link for Nest Thermostat E	Something needs your attention.
Yellow	3rd Gen Nest Learning Thermostat, 2nd Gen Nest Learning Thermostat	The thermostat is disconnected from the Heat Link.
Yellow	2nd gen Nest Learning Thermostat	The heat Link is in manual mode.

Red

A red flashing light on the Nest thermostat indicates that the battery is low but is currently charging.

How to Fix:

If your Nest thermostat has a blinking red light, you do not need to take any action.

Follow these steps to speed up the charging:

Remove the display from the base.
Connect a USB cable to the USB port and plug it into a wall outlet.
Once fully charged, place the device onto its base.
Press firmly until you hear a clicking sound to ensure the Nest thermostat is properly attached.

A frequently recurring blinking red light could indicate a problem with your Nest thermostat’s wiring. You may need to connect a common wire to your device’s control board to resolve this issue.

Blue

If your Heat Link for Nest Thermostat E or 3rd Gen Nest Learning Thermostat displays blue lights, it can mean one of several things.

Heat Link for Nest Thermostat E

During setup or re-establishing a Nest App connection, a Heat Link for Nest Thermostat E will slowly flash blue.

When the blue light blinks faster, it means that the device is performing a software update.

Heat Link for 3rd Gen Nest Learning Thermostat

If you have a 3rd Gen Nest Learning Thermostat, a slowly flashing blue light indicates that the Heat Link is waiting to connect to your device.

Green

Depending on your Nest Thermostat type, a green light can have different meanings.

Heat Link for Nest Thermostat E

On a Heat Link for Nest Thermostat E, a blinking green light signifies that your device is controlling your heating system.

A solid green light indicates that manual heating mode via the Heat Link is on.

Heat Link for 3rd Gen Nest Learning Thermostat

A solid green light on a Heat Link paired with a 3rd Gen Nest Learning Thermostat means that the device is on and operating normally.

If the hot water or heating functions are manually activated on the Heat Link, these indicator lights will also light up green on your thermostat.

Heat Link for 2nd Gen Nest Learning Thermostat

If you have a 2nd Gen Nest Learning Thermostat, a constant green light indicates that your device is actively paired with the Heat Link.

A green flashing light signifies that heating has been engaged.

Blinking Green Light on a Nest Thermostat

On any Nest Thermostat, a flashing green light means the device receives a software update. This process should last a few minutes at most.

What To Do if a Nest Thermostat Is Stuck on an Update?

If your Nest Thermostat has a blinking green light lasting 15 minutes or longer, it may be frozen or stuck on an update.

To resolve this issue, detach the device from its base and re-install it to clear the error. You can also manually restart the Nest Thermostat through the Settings menu.

Orange

An orange flashing Nest thermostat means the same as a flashing red light. It needs to be recharged because the batteries are low.

An orange light can also indicate that the device is in heating mode on a Nest Learning Thermostat or Nest Thermostat E.

For some users, a blinking orange light with a green light can indicate a heating problem. Air will come from your HVAC vents, but it will not be warm. You would be best served by contacting tech support for assistance.

Yellow

A yellow light on your Nest thermostat has different meanings depending on which model you have in your home.

Heat Link for Nest Thermostat E

A flashing yellow light on a Heat Link for Nest Thermostat E indicates that something needs your attention. This could relate to paired systems such as water boilers or heat pumps.

Check your Nest Thermostat face to identify the problem or issue.

Heat Link for 3rd Gen Nest Learning Thermostat

A solid yellow light on your 3rd Gen Nest Learning Thermostat indicates that your device has disconnected from the Heat Link.

When this happens, your thermostat cannot control heating or hot water in your home. However, these can be manually activated on the Heat Link.

Heat Link for 2nd Gen Nest Learning Thermostat

A flashing yellow light on a 2nd Gen Nest Learning Thermostat means that heating functions are being manually controlled through the Heat Link.

White

If the Nest Thermostat is blinking white, it is reconnecting to the router. Nest Thermostats have limited functions if they’re not connected to the internet.

If you have the WiFi error W5 on a Nest Thermostat, there are some quick fixes you can do.

Other Nest Thermostat Flashing Colors

As we have seen, the Nest thermostat uses many colors to communicate with you. Are there any other colors the Nest thermostat will flash to notify you?

Yellow and Green Flashing Together

On a 2nd Gen Nest Learning Thermostat, yellow and green lights may occasionally be seen flashing together.

When the green and yellow lights alternate every other second, the Heat Link is searching for a thermostat to pair with.

If the green and yellow lights blink quickly, the Heat Link is resetting to the factory default settings.

Green Leaf With Lightning Bolt

If you enroll in the Nest Renew program, you may see a green leaf with a lightning bolt on your Nest Thermostat.

This symbol indicates that your heating or cooling has been adjusted to take advantage of cleaner energy or lower rates.

A leaf icon without a lightning bolt indicates that your Nest Thermostat has activated Eco mode. This typically happens when your device fails to detect the presence of anyone in your home.

No Lights

When your Nest Thermostat is functioning normally, you will not see any lights.

However, a blank screen can also occur during a power outage. If your device is unexpectedly offline, you should see an error message on your Nest Thermostat display or in the app.

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