How Do I Fix My Nest Thermostat With Low Battery?

All we know is that the Nest thermostat receives power from the HVAC system. All thermostats you use, whether 1st, 2nd, or 3rd generation, all come with inbuilt batteries.

A Nest thermostat is the best investment you can make because it will help you save money on bills. You might be struggling to charge your thermostat and may have a question in your mind.

How do I fix my Nest thermostat with low battery? Today, in this article we are covering all the important basics and other things you need to know to fix the battery problem. And, in the end, you will be an expert! So, without wasting time let’s get started.

The lifespan of a Thermostat Battery?

Without charging from the HVAC system, the thermostat battery can last from a couple of hours to a few days. Battery life depends on uninterrupted charging from the HVAC system.

The continuous flowing of power can save your battery and can last for 5 to 10 years without any problem. However, if there is tension in the battery, it may last for 2 years only. 

How Can You Check the Battery Level of Your Thermostat?

How Do I Fix My Nest Thermostat With Low Battery 1

If you find your thermostat is running on low batteries then your first call of action should be to check on the battery level. To determine the level of your thermostat you have to follow the below steps.

  • First, check the Quick View Menu, and press and hold the thermostat ring until you see that.
  • Go to settings >> Technical information >> Power. 
  • If you find out the battery is 3.7V or higher than this, your thermostat should be disconnected because of the low battery. And, the lin current should be over 20mA.
  • However, when you find out the lin current is below 20mA and the battery level is below 3.7V then your battery indicates a low battery sign.

How Do I Fix My Nest Thermostat With Low Battery?

As we already discussed, the Nest thermostat maintains its charging from the Rh or RC wiring from the HVAC system. That means when your HVAC system runs, it charges the thermostat automatically.

You do not need to charge it manually. If you are facing a low battery warning continuously, the battery is not charging itself, or else your thermostat has died. There are a few ways to fix this issue.

Step 1: Check the Base Connection of Your Nest Thermostat

Sometimes it happens when the thermostat is not set up with the base and the connectors are not lined up, this stops the flow of power. 

Step 2: Charge it With USB Cable

When your thermostat indicates the sign of battery is low, use the USB port back of the Nest Thermostat. 

  • Remove the thermostat display.
  • Plug it into the USB port which you use to charge your phone or in your computer device. 
  • A light will start blinking in front of your thermostat and that’s the confirmation of charging. And, the color of the light depends on the percentage or level of charging of your thermostat. It normally takes half an hour to charge the battery but if the batteries are fully drained, it may take up to 2 hours to charge fully. 

Step 3: Charge your battery manually

If you have an earlier Nest thermostat model then you’re lucky who can charge their battery manually. Plug a USB cable in your Nest thermostat, it will quickly fix the battery problem and will start charging the battery.

But keep this thing in mind, this is a temporary solution. This manual charging will decrease the efficiency of the battery. 

Step 4: Replace the battery

If you are still facing the same issue, not charging the battery even after holding the charger then there are chances your battery is dead. Replacing your battery is the only option, now open your thermostat compartment and remove the battery.

And, insert a new one. But if you are not able to replace it or get confused then call their customer care. 

Step 5: Reset or Restart

Honestly, it works sometimes and this should be your last effort. Once you restart your Nest thermostat then plug in a USB or wall charger into this. 

Tips to Solve the Battery Issues

  • Once you buy a new Nest thermostat for your home, register with the Google Nest app. This will help you to secure your right to a limited warranty. This warranty can last one to two years. 
  • If you are going to call customer service, I recommend you check the limitation to avoid wasting time and explain the situation better. 
  • Keep your HVAC system neat and clean for better function. Alos, change the filters from time to time. 
  • If you have a mouse at your home and suddenly, you are facing a problem in the thermostat then you should call an electrician in order to check the wires. All we know is that the mouse can chew the wires. 
  • If you are living in an older home and the wiring of this home is 20 or more years older then you must check the wiring before taking action against the thermostat. 

How Long Nest Thermostat Battery Can Last?

How Do I Fix My Nest Thermostat With Low Battery Level

To charge the battery thermostat uses the voltage in the cable. When the power is shut, the battery can stay for a maximum of 2 to 3 hours.

You will notice when the thermostat is running on low power the display will be turned off and wifi connection also be disconnected automatically.

This wifi and display thing happens to save the battery for a little longer time. You can’t control your Nest thermostat via an app when it’s running on low battery. 

How to Replace the Nest Thermostat Battery?

You should buy a high-quality 1.5V triple-A alkaline before replacing the batteries from your Nest device. 

  • First, remove the display from its mounting base by pulling that outwards. 
  • Remove the old batteries from your Nest thermostat and set them aside. 
  • Now, replace the old batteries with new AAA batteries. 
  • You have to push the display back onto the base. 


I hope you understand now, how to deal with your Nest thermostat with its showing low battery. You can easily fix the problem now because we already discussed everything above.

I would also give you another piece of advice to install UPS or generators if power interruption is very common in your area. Nest thermostat batteries are for backup in the device and they can not stay for a longer period of time. 


Also Read: How to Charge Nest Thermostat with & without C-Wire

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