What do the screen colors on a Nest thermostat mean?

On the Nest Thermostat E and Nest Learning Thermostat, Google says the display changes between orange for heating, blue for cooling and black for off or Eco. Google's troubleshooting page adds that when the screen changes color, the thermostat is trying to turn your system on.

Does every Nest thermostat learn a schedule?

No. Google says only the Nest Thermostat E and the Nest Learning Thermostats have Auto-Schedule. The Nest Thermostat, the 2020 model, does not. On the models that have it, Auto-Schedule is on by default.

Why does my Nest thermostat start heating before the scheduled time?

That is Early-On. Google says the thermostat can start heating or cooling early so the home reaches the scheduled temperature on time, and can begin heating up to 5 hours ahead. It only does this when someone is home.

What temperatures can I use for Eco?

Google gives the Eco ranges as 40 to 70°F for heating and 76 to 90°F for cooling. When you switch to Eco by hand, the thermostat ignores the schedule until you switch it back to heating or cooling.

Google Nest thermostats: messages and settings explained

Google Nest thermostats speak mostly in colors and short messages. An orange screen means the thermostat is asking for heat, blue means cooling and black means off or Eco. Many settings live in the Google Home app rather than on the thermostat. This page explains how the models differ and links to a page for each message.

Which Nest thermostats does this site cover?

Google sells and supports several models, and they do not all behave the same way. The ones its help pages distinguish are:

Nest Learning Thermostat (4th gen)
Nest Learning Thermostat (3rd gen and earlier)
Nest Thermostat E
Nest Thermostat, the model released in 2020, which runs on two AAA batteries

The differences matter for some messages. A blinking red light means a low battery that is charging on the Thermostat E and the Learning Thermostat up to the 3rd gen, while the 4th gen shows dark yellow instead. Learning features also differ by model, as the FAQ below explains. Each page on this site names the model a fact applies to.

How do you read a Nest thermostat screen?

Two numbers and a color tell you most of what is going on. Google says the large number in the center is the target temperature, and the small number near the edge is the current temperature measured by the thermostat's sensors. If a Nest Temperature Sensor is active, the display shows that sensor's reading instead.

On the Nest Thermostat E and Learning Thermostat, the color shows what the thermostat is doing: orange while heating, blue while cooling, black when it is off or in Eco. Google's troubleshooting page says a color change means the thermostat is trying to turn the system on. If the screen is orange or blue and nothing starts, the thermostat is asking but the system is not answering, which is a different problem from a thermostat that never asks.

Where are the settings?

Some are on the thermostat and some only in the Google Home app, and the split depends on the model. The ones readers ask about most:

Maintenance band. Google's name for the temperature differential: the drift the thermostat allows before starting the system. It adjusts the band automatically. On the Learning Thermostat (4th gen) you can change "Heat temperature difference" and "Cool temperature difference" in Advanced configuration in the Home app.
Compressor lockout time. The minimum time between compressor cycles, also in Advanced configuration. This is Nest's version of compressor protection.
Heat Pump Balance. For heat pumps with auxiliary heat (AUX): Max Comfort (the default), Balanced, Max Savings or Off. Google says AUX heat can cost about 2 to 5 times as much as running the heat pump.
Early-On. Starts heating or cooling early so the house reaches the scheduled temperature on time.
Eco temperatures. The setpoints used when nobody is home or when you choose Eco.

What do the common Nest messages mean?

Each has its own page:

A flashing red light on the ring or display: Nest thermostat flashing red light.
"Delayed" or "Starts in" on the screen: Nest thermostat says "Delayed".
The thermostat switching to Eco on its own: Nest Eco mode turns on by itself.
AUX on a heat pump system: why your thermostat shows AUX.

For settings that work the same way across brands, see the temperature differential and recovery mode.

Every Google Nest page on this site

How Nest Auto-Schedule learns, and how to turn it off
How does Nest Auto-Schedule work?
Nest "No power to Rh wire" message
What does "No power to Rh wire" mean on a Nest thermostat?
Nest Eco mode turns on by itself
Why does my Nest thermostat switch to Eco on its own?
Nest Eco temperatures explained
What are Eco temperatures on a Nest thermostat?
Nest Eco vs ecobee Away vs Honeywell Away
What do Eco and Away modes actually do on each brand?
Nest Heat Pump Balance explained
What does Heat Pump Balance do on a Nest thermostat?
Nest thermostat flashing red light
What does a flashing red light on a Nest thermostat mean?
Nest thermostat low battery warning
Why does my Nest thermostat say the battery is low?
Nest thermostat says "Delayed"
Why does my Nest thermostat say "Delayed"?
Room sensors vs the thermostat sensor
Which temperature does the thermostat use when you have room sensors?

Frequently asked questions

What do the screen colors on a Nest thermostat mean?: On the Nest Thermostat E and Nest Learning Thermostat, Google says the display changes between orange for heating, blue for cooling and black for off or Eco. Google's troubleshooting page adds that when the screen changes color, the thermostat is trying to turn your system on.
Does every Nest thermostat learn a schedule?: No. Google says only the Nest Thermostat E and the Nest Learning Thermostats have Auto-Schedule. The Nest Thermostat, the 2020 model, does not. On the models that have it, Auto-Schedule is on by default.
Why does my Nest thermostat start heating before the scheduled time?: That is Early-On. Google says the thermostat can start heating or cooling early so the home reaches the scheduled temperature on time, and can begin heating up to 5 hours ahead. It only does this when someone is home.
What temperatures can I use for Eco?: Google gives the Eco ranges as 40 to 70°F for heating and 76 to 90°F for cooling. When you switch to Eco by hand, the thermostat ignores the schedule until you switch it back to heating or cooling.