my nest learning thermostat keeps switching to eco mode when i'm home, i don't want it to do that

Diagnosis

The Google Nest Learning Thermostat (4th Gen) utilizes a feature called Home/Away Assist to automate energy savings. When the device switches to Eco mode while you are present, it is experiencing a "false away" trigger. This happens because the system relies on a combination of the thermostat's built-in PIR (Passive Infrared) motion sensor and the geofencing data from your smartphone's GPS. If the thermostat is installed in a low-traffic hallway or behind a door, the onboard sensor may fail to detect movement for a period of 30 minutes to 2 hours, leading the device to conclude the house is empty. Furthermore, the 4th Gen model integrates deeply with the Google Home app's "Presence Sensing" logic. If your phone's location permissions are set to "While Using the App" instead of "Always," or if battery optimization settings are putting the Google Home app to sleep, the system will stop receiving "Home" pings from your mobile device. When the thermostat sensor is blind and the phone location is stale, the system defaults to the Eco temperature setpoints to prevent energy waste, regardless of your actual presence.

How to Fix It

To stop the thermostat from autonomously switching to Eco mode, you must refine the Presence Sensing triggers within the Google Home app. Follow these exact steps:

1. Open the Google Home app on your primary mobile device.
2. Tap the Settings gear icon in the bottom right or navigate to the Devices tab and select your Thermostat.
3. Scroll down to Presence Sensing (found under the "Home & Away" or "Automations" section depending on your app version).
4. Locate the list of devices used to determine presence. Toggle OFF the "Learning Thermostat" as a presence sensor if it is located in a room where you don't spend much time. This prevents the PIR sensor from overriding your phone's location.
5. Ensure your smartphone is toggled ON in this list.
6. Exit the app and go to your phone's System Settings > Apps > Google Home > Permissions.
7. Change the Location permission to "Allow all the time". If it is set to "Allow only while using the app," the thermostat will switch to Eco the moment you lock your phone screen.
8. Disable Battery Optimization for the Google Home app to ensure the GPS ping remains active in the background.

If That Didn't Work

• Disable Home/Away Assist entirely: If you prefer manual control over automation, go to the thermostat's physical dial, push the ring to open the menu, select Settings > Home/Away Assist and toggle the feature to Off. This completely kills the automated Eco switching.
• Check for "Eco" Schedules: Ensure you haven't accidentally created a scheduled Eco event. In the Google Home app, check the Schedules tab. Look for any "Eco" blocks that may have been automatically learned from your previous habits. Delete any blocks that conflict with your current home hours.
• Add Additional Presence Sensors: If you have other Nest devices (like a Nest Protect smoke detector or a Nest Cam) in high-traffic areas, enable them as presence sensors in the Google Home app. This provides the system with more "eyes" to confirm you are home, reducing the chance of a false Eco trigger.
• Reset the Learning Phase: If the thermostat has "learned" a bad habit, go to the physical device, navigate to Settings > Reset > Schedule. This clears the learned patterns and forces the device to start fresh based on your current manual adjustments.

Heads Up

• Sensor Obstructions: Ensure there are no curtains, furniture, or decorative covers blocking the front of the thermostat. The PIR sensor has a limited field of view; even a partial obstruction can trigger Eco mode.
• Eco Temperature Gap: Check your Eco temperature settings. If your "Eco" heat is set to 62°F and your "Home" heat is 72°F, the jump is drastic. Setting a narrower gap can make accidental switches less disruptive.
• Connectivity Drops: If your Wi-Fi signal is weak (indicated by a "W5" error or intermittent offline status), the thermostat may lose contact with the Google Home cloud and default to Eco mode as a fail-safe. Consider a Wi-Fi extender if the signal is below -65 dBm.