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Whenever somebody’s home, your Nest thermostat can use Early-On to start heating or cooling early so that your home will reach the scheduled temperature on time. Simple programmable thermostats will only start heating or cooling at the time you’ve scheduled. They don’t take into account how long it takes for your home to heat and cool, so your home won’t reach the scheduled temperature until later.

When Early-On is enabled, your Nest thermostat automatically calculates how early it should turn on heating or cooling so your home will reach a scheduled temperature on time. To do this, your thermostat takes into account the weather, what it has learned about how quickly your home warms and cools, and how efficient your system is.

Early-On works a lot like preheating the oven when you’re making cookies. You typically start heating your oven a few minutes ahead of time so that it’s the right temperature when you’re ready to put your batch of cookies in to bake. Now imagine that your oven knew you’d be done mixing the dough at 5 PM and would automatically turn on early to be 350°F/175°C right at 5 PM.

Early-On basics 

Early-On learns about your home and system

After installation, your thermostat will take a few days to learn how long it takes for your home to heat and cool. During this period, in order to save energy your thermostat will not preheat or precool your home regardless of your Early-On setting. Once your thermostat is done learning, it can start preheating and precooling according to your Early-On settings. 

Without Early-On

If your thermostat’s still learning about your home, or if you disable Early-On, here’s what to expect: 

  • Your thermostat will start heating or cooling your home at the scheduled time.
  • For example, if your schedule has a target temperature of 72°F/22°C at 6:00 PM, your thermostat will start heating or cooling at 6:00 PM. So your home may not reach 72°F/22°C until much later than 6:00 PM. Time-to-Temperature will show you about how long it will take for your home to reach the target temperature.

With Early-On

After your thermostat has learned about your home, here’s what to expect when Early-On is enabled:

  • Your thermostat will start heating or cooling your home before the scheduled time, using what it has learned about your home to predict how long it will take to reach the target temperature.
  • For example, if your schedule has a target temperature of 72°F/22°C at 6:00 PM, your thermostat might start heating or cooling at 5:30 PM to get your home to 72°F/22°C at 6:00 PM.

When Early-On starts, your system varies based on factors like the weather and how long it’s taken to heat or cool your home in the past. If you enable Early-On, your thermostat can begin heating up to 5 hours before a scheduled temperature.

graph 1 shifted image

How Early-On learns 

Early-On will continually adapt to the weather forecast and how fast your home heats up or cools down. This is to improve its Time-to-Temperature estimates and keep you comfortable while it helps you save energy.

For example, on a cold day the Nest thermostat might need to start heating at 5:00 AM to reach your target temperature by 7:00 AM. But on a mild day, the thermostat may only need to start heating at 6:50 AM.

Early-On won't activate if everyone's away 

If you use Home & Away Routines (Home app) or Home/Away Assist (Nest app), Early-On can turn your system on early to reach your scheduled temperature on time as long as someone is home.

But if everyone is away and your thermostat switches to Eco temperatures, it will try to stay in Eco until someone comes home. This means that it will wait to start preheating or precooling your home until someone comes home or until someone manually changes the temperature in the app.

How to change Early-On settings 

You can change Early-On settings on your thermostat or with the Nest app. In some homes, Early-On may use more energy because it will run your system longer. You can either limit the preheating time or turn Early-On off to help save energy.

With the Nest app

  1. Open the Nest app and tap your thermostat.
  2. Select Settings Nest settings icon.
  3. Tap Early-On.
  4. Choose the following options:
  • Tap the switch to enable or disable Early-On.
  • Select Max Duration to limit preheating in the middle of the night and early morning. This can be useful if your system is noisy and you don’t want it to wake you up too early.

With the Home app

  1. Open the Home app Google Home app.
  2. Touch and hold your device's tile.
  3. At the top right, tap Settings  and then Temperature preferences and then Early-On.
  4. You have two options to set:

On the Nest Learning Thermostat or Thermostat E

  1. Press your thermostat ring to open the Quick View menu.
  2. Select Settings Nest settings icon.
  3. Select Nest Sense.
  4. Select Early-On.
  5. Choose the following options:
  • Select Start early to enable Early-On, or select On schedule to disable Early-On.
  • Select Max Duration to limit preheating in the middle of the night and early morning. This can be useful if your system is noisy and you don’t want it to wake you up too early.

Note: If you have a radiator and air conditioning, you'll choose the Max Duration in the Heat Pump Balance menu.

Early-On may help save energy in your home 

With your old thermostat, if you wanted your home to be warm by 9:00 AM every day, you might have scheduled heating to start at 8:00 AM. Early-On can calculate how long it will take to heat your home in the morning, and it may not need the full hour of extra heat to keep you comfortable. On a mild day, it might only need to start heating at 8:50 AM.

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Early-On is great if you’ve been guessing and setting your own “Early-On” temperature in your schedule. Now, you can set your schedule for the temperature you want when you want it, and Early-On will take care of the rest.

Troubleshoot when Early-On settings are missing 

Nest thermostats detect what wires you have inserted into the connectors and use System Match to tell what kind of heating and cooling system you have. If Early-On isn’t compatible with your system, settings won't be available in the app or on your thermostat.

So you may have an incompatible system, or there could be a wiring issue that makes your thermostat think you have an incompatible system.

Check what kind of system you have installed, then check your thermostat wiring:

  1. If your system warms the floors or radiators in your home, you have a radiant system. Early-On doesn’t work with radiant systems. They use True Radiant instead to manage preheating.
  2. If your system blows air through vents in your home, you have a forced air system, and there should be Early-On settings. If not, your thermostat may not be wired correctly or may think it’s connected to a different type of system.
  3. Check your thermostat’s wiring by pulling off the display. If there’s no wire in the G connector, your thermostat may assume it's connected to a different type of system because G wires control the fans that push air through the vents in your home.
  4. Check your heat type by going to Settings Nest settings icon  Equipment  Heat Type on your thermostat. Make sure to select the type of heating that you have: Forced AirIn-floor radiant, or Radiators.
  5. If you think that the wires are configured incorrectly, contact a professional HVAC technician to help you correct your system wiring and setup.

If you have more than one type of system

  • If you have a heat pump with auxiliary heat, how early your system will start cooling your home is determined by Early-On. How early your system will heat your home is determined by Heat Pump Balance.
  • If you have a radiator system and a cooling system, True Radiant will control how early your home preheats and Early-On will control how early your system precools.
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