Google Nest Thermostat Troubleshooting: Heating, Cooling & Connectivity

Easy 15-30 minutes

The Google Nest Thermostat is a popular smart thermostat known for its learning capabilities and energy-saving features. This guide covers common issues with temperature control, connectivity, and the Nest app.

Thermostat Not Heating or Cooling

Check the Basics

  1. Verify the thermostat is set to "Heat," "Cool," or "Heat • Cool" mode (not "Off")
  2. Check that the target temperature is set above (for heating) or below (for cooling) room temperature
  3. Look for any schedule that might have changed the temperature
  4. Check if Home/Away Assist has set the thermostat to Eco mode

Thermostat Shows "Delayed" Message

This is a safety feature that protects your HVAC system:

  • Wait 2-5 minutes—the system should start automatically
  • If it happens frequently, check your C-wire connection
  • The Nest may be underpowered—consider adding a C-wire or Nest Power Connector

System Short Cycling (Turning On and Off Quickly)

  • Often caused by power issues—check the C-wire or add the Nest Power Connector
  • Air filter may be clogged—replace it
  • System may be oversized for your home—consult an HVAC professional
  • Check that the thermostat is level and properly mounted to the base

HVAC System Not Responding at All

  1. Check your circuit breaker—reset if tripped
  2. Verify the Nest display shows power (not blank)
  3. Go to Settings → Equipment and run a test for each system
  4. Check wire connections at the thermostat base
  5. Check wire connections at your furnace/air handler

Temperature Reading Issues

Thermostat Shows Wrong Temperature

  • Temperature sensor is in the thermostat—location matters greatly
  • Avoid installing near: direct sunlight, exterior walls, air vents, drafty areas
  • Electronics and lamps nearby can affect readings
  • Compare with a separate thermometer at the same location

Room Temperature Doesn't Match Setting

  • Normal variance is 1-2°F—HVAC systems aren't perfectly precise
  • Check for drafts, poor insulation, or blocked vents in the room
  • Large temperature swings may indicate system sizing issues
  • Adjust temperature differentials in Settings → Equipment → Continue → Heating/Cooling differential

Using Nest Temperature Sensors

If you have remote Nest temperature sensors:

  • Make sure the sensor is active (check in app)
  • Verify which sensor is being used for control (Settings → Temperature Preferences → Temperature Sensors)
  • Sensors work best at chest height, away from sunlight and vents

WiFi and Connectivity Issues

Thermostat Won't Connect to WiFi

  1. Nest Thermostat supports 2.4GHz and 5GHz WiFi
  2. Check that WiFi password is correct
  3. Move router closer or add a WiFi extender
  4. Check for router firmware updates
  5. Try forgetting the network and reconnecting

Thermostat Shows Offline in App

  • Check home internet connection
  • Restart the thermostat: pull it off the base, wait 10 seconds, reattach
  • Restart your router
  • Check WiFi signal strength in Settings → Technical Info
  • Google may be having server issues—check Google Nest status page

Can't Control Thermostat Remotely

  • Thermostat must be connected to WiFi
  • Verify you're logged into the correct Google account
  • Check that the thermostat appears in your Nest or Google Home app
  • Try signing out and back into the app

Battery and Power Issues

Thermostat Display is Blank or Won't Turn On

  1. Pull the thermostat off the base and plug into USB charger for 30 minutes
  2. Check that wires are securely connected to the base
  3. Check your circuit breaker
  4. Verify your HVAC system has power (check furnace switch)
  5. If using only heating wires (no C-wire), the battery may have drained

Low Battery Warning

Nest thermostats charge from your HVAC system. Low battery indicates a power problem:

  • Your system may not have a C-wire (common wire)—consider adding one
  • Install the Nest Power Connector at your furnace (no new wiring needed)
  • Check that heating/cooling runs long enough to charge the battery
  • Make sure system isn't short cycling

Battery Draining Quickly

  • Frequent WiFi disconnections drain battery faster
  • Very old furnaces may not provide enough power
  • A blown fuse in your furnace can reduce power
  • Consider adding a C-wire for reliable power

Schedule and Learning Issues

Thermostat Not Following Schedule

  1. Check if Home/Away Assist is overriding the schedule
  2. Verify the schedule in app: Settings → Schedule
  3. Manual adjustments create "learning" that can override schedules
  4. Turn off "Auto-Schedule" if you want strict schedule control

Learning Feature Not Working Well

  • Nest needs 1-2 weeks to learn your preferences
  • Make manual adjustments when you want the temperature changed—this teaches Nest
  • If learning creates bad schedules, go to Settings → Reset → Schedule to start over
  • You can disable Auto-Schedule and create a manual schedule instead

Home/Away Assist Not Working

  • Everyone in the home needs the Nest app with location permissions enabled
  • Check that Home/Away Assist is turned on in app settings
  • The thermostat can also use its built-in sensor—ensure it has a clear view of the room
  • It may take hours for the thermostat to switch to Away mode

App and Integration Issues

Thermostat Not Appearing in App

  1. Ensure you're using the Google Home app (Nest app is being phased out for newer devices)
  2. Make sure you're signed into the correct Google account
  3. Check that the thermostat is set up and connected to WiFi
  4. Try removing and re-adding the thermostat

Google Assistant/Alexa Not Controlling Thermostat

  • Verify the thermostat is linked in Google Home or Alexa app
  • Check that the thermostat is online
  • Use the exact name: "Set living room thermostat to 72 degrees"
  • Try unlinking and relinking the account

Energy History Not Showing

  • Energy history takes a few days to populate
  • Thermostat must be connected to WiFi to log data
  • Check in Google Home app under the thermostat's settings

Display Issues

Display Too Dim or Too Bright

  • Nest has a light sensor—display adjusts to room brightness
  • Check Settings → Display → Brightness for manual adjustment
  • Farsight can be turned on to show temperature when you approach

Screen Frozen or Unresponsive

  1. Press and hold the thermostat ring for 10 seconds to restart
  2. If still frozen, pull it off the base and reattach
  3. As a last resort, pull off the base and charge via USB, then reattach

Error Codes

E73, E74, E75 (Power Errors)

  • These indicate the Nest isn't getting enough power from your HVAC system
  • Add a C-wire or Nest Power Connector
  • Check for blown fuse in furnace
  • Ensure wires are properly connected

N260, N261 (No Power to Rh or Rc Wire)

  • Check wiring at both thermostat and furnace/air handler
  • Check circuit breaker and furnace power switch
  • Check for blown fuse at furnace (usually 3-5 amp)

Factory Reset

If problems persist, factory reset the thermostat:

  1. Go to Settings → Reset → All Settings
  2. Or: Press and hold the ring for 10+ seconds until it restarts, then press again to access reset menu
  3. This removes all settings and schedules but keeps it on your account
  4. To fully remove: also go to the Google Home app and remove the device

When to Contact Support

Contact Google Nest support or an HVAC professional if:

  • Error codes persist after troubleshooting
  • Wiring is damaged or unclear
  • HVAC system makes unusual noises
  • You're uncomfortable working with HVAC wiring

Google Nest support: support.google.com/googlenest or call 1-855-469-6378