Nest thermostat keeps restarting? Here’s the likely cause

⚡ Fast fix

• Power problem: Most restart loops come from weak or unstable power.
• Check the C-wire: Make sure it’s connected—or install a power connector.
• Quick charge: Plug in via USB for an hour if the battery is drained.
• Loose wiring: Reseat wires and check for low voltage (aim for ~24V AC).

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When your Google Nest Thermostat® keeps restarting, you can’t use its smart features. It’s confusing and frustrating, but you’re not alone. The team at Asurion learn tech inside and out to help with everything from installing new computer software to troubleshooting common smart thermostat problems. Try these steps if your Nest Thermostat keeps restarting all the time.

Check power and wiring connections

A Nest Learning Thermostat that keeps restarting often has a power issue.

Start by checking the C-wire connection. The C-wire, or common wire, is what provides continuous power to your smart thermostat. If you didn’t have a spare wire when you installed your thermostat, you probably used a Nest Power Connector.

Make sure either the C-wire or the Nest Power Connector is plugged in properly with a strong connection. Check that it has proper seating in the base plate. You don’t want the wires rubbing against anything and wearing down.

Look for low voltage or poor power draw from the HVAC system. You can test this with a multimeter to measure voltage. The result should be 24V AC.

If you notice any loose wires, reseat them. Use an adapter if necessary. Any wiring or power issues can cause the Nest Thermometer to lose continuous power access, making it continually restart.

Look for HVAC or compatibility problems

If the thermostat power and wires don’t seem to be the issue, it’s time to take a closer look at your HVAC system.

Your system may be short-cycling, turning on and off prematurely, because your furnace is overheating. HVAC wiring issues can also cause short-cycling. Make sure there are no restrictions to airflow, such as dirty filters or blocked vents, that could be causing your furnace to overheat. Also, check for damage or loose wires at the furnace control board.

When the furnace shares a circuit with accessories like humidifiers, that may also interrupt power flow at times, making the Nest Thermostat E keep restarting.

If your Nest Thermostat power issues persist and none of the DIY troubleshooting steps help, consider contacting a professional technician for help. It’s especially important to call a technician if you notice signs of electrical failure, such as:

• Burning smell
• Buzzing sound from breakers
• Signs of voltage drops, like dimming lights

A trained technician can safely perform voltage and compatibility checks to hopefully figure out the root cause of your Nest Thermostat problems.

Fix software and restart loop issues

It’s also possible that the Nest Thermostat software could be causing the Nest reboot loop.

Try turning off your Google Nest, waiting a minute or two, then turning it back on. You can also run a soft restart by going to Settings > Reset > Restart. A restart will keep all your settings and potentially fix minor software problems causing the restart loop.

Then, check for any available updates. Your thermostat should update automatically, but in case it didn’t, go to Settings > Version > Update. For older models (E or 3rd generation), go to Settings > Software Update. Install the update if it’s available.

If the restart problems persist, try a factory reset. This will erase your settings and bring the Nest back to default settings. Follow these steps:

1. Select Settings > Restart or Factory Reset.
2. Confirm your choice.
3. Set up the Nest Thermostat again and follow the steps to add it to your Google Home app.

If your Google Nest won't connect to Wi-Fi after you restart it, make sure your Wi-Fi is working by testing it with another device. Then, try moving your router closer to your Nest and restarting it to get the connection back.

If your Nest Thermostat goes back to continually restarting even after you’ve performed a factory reset and followed the other troubleshooting steps, the thermostat hardware may be the problem. Consider buying a new one or looking into other options for the best smart thermostat for your home.

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FAQ

Why does my Nest thermostat keep restarting?

Most commonly, it’s due to a power issue—like a missing or loose C-wire—or low voltage from your HVAC system.

Can a low battery cause a Nest thermostat to restart?

Yes—if the battery can’t hold a charge, the thermostat may reboot repeatedly.

How do I fix a Nest thermostat reboot loop?

Check wiring, confirm steady power (24V), restart the device, and update the software.

When should I replace my Nest thermostat?

If it keeps restarting after fixing power, wiring, and software issues, the hardware may be failing.