How to change batteries in your Honeywell or Emerson thermostat (EASY Steps)

Most thermostats have a battery to store the settings when the power goes out. These settings determine when the heating system in your home has to work. It saves energy as your heating system doesn’t have to work when you don’t need it. This battery might need to be replaced from time to time. Changing the batteries in your thermostat is not as scary as it sounds. However, it is a bit of a hassle. Luckily, we have explained how to change batteries in your thermostat so that you can save yourself some time and trouble in the future. 

What batteries does a Honeywell thermostat use?

Thermostats generally use AA batteries. Some also use custom batteries. You will have to check the manual or Google your model number to make sure that you get the correct ones for your device.

Thermostats can require multiple batteries. There is often an indicator on the screen that warns you when the batteries are running low. If you notice this, it might be a great moment to order new ones. These batteries generally last a few years so you shouldn’t have to replace them too often. 

Make sure that the batteries that you buy have the right wattage as cheaper versions are often less strong. Your thermostat might not work when you use them. Rechargeable batteries should work just fine.

It is best to do this during summer or fall so that you are prepared for winter. It is annoying if your heating system doesn’t work when you need it. To avoid this, it is best to schedule maintenance of your heating system during the fall as well. Plumbers are very busy during the winter so you might have to wait a long time before you get serviced. 

How to change batteries in a Honeywell or Emerson thermostat

To change the batteries in your thermostat, you will generally need to follow these steps: 

  • Find the button on the panel that allows you to open it. 
  • Press this button and open up the panel. Some models don’t have a button and you just have to pull the panel open. Be careful when you do this as most thermostats are made out of plastic and can be quite fragile.
  •  Once you have opened up the panel, you should see the batteries. They are often located on the top of the panel. 
  • Now it is time to remove the batteries. If you are not able to remove the batteries, you can use a small prying tool.
  • Once the batteries have been removed, you can install the new ones. Check the instructions on the panel to see in what direction the batteries have to be installed. This has to be correct or the batteries won’t work properly.
  • Now we can close the panel. Make sure that it clicks together properly. Don’t force things. Start on the opposite side of the button that closes the panel.
  • The last step is to verify that the thermostat gives a signal that the battery level is high again. You will generally get an icon with the battery level on the screen (you might have to press some buttons in the menu if you don’t see it).

These steps work for most Honeywell thermostats. These are the most popular in the USA so chances are that you have one of these brands as well. 

Some smart thermostats make it harder to replace the battery. The Nest thermostat is an example of this. It is best to wear rubber gloves when you work on this. Start by removing the cover plate. You will need a Philips screwdriver to open up the part that holds the batteries. Check in the video below what screws need to be removed. Be careful with the connections as these cables can be quite fragile. This is something that a lot of people break if they are not careful.

It is best to get a small plastic prying tool to remove the battery. Clip the connector of the battery in place and close the thermostat again. You should get a confirmation that the battery is full. If you are not comfortable doing this, you can ask an electrician to do this for you.

 If this doesn’t work for your thermostat, you can look up the manual online to see how it needs to be done. Some manufacturers make it harder to replace the batteries. Keep in mind that opening the device might void the guarantee. 

When you are replacing the battery, it might also be a great idea to think about getting a new thermostat. Newer ones are more energy-efficient as they learn how you live. They are able to turn down the heating when you aren’t at home and turn it on when you are. These advanced features can make it worth it to upgrade to a newer system.

If you don’t want to get a new thermostat, you can also check the current settings. Most people tend to heat their homes too much. For example, you can turn down the heat after a certain hour so that you don’t heat the home while you are in bed. All these small tweaks can add up and save a lot on your heating bills. We have discussed how to troubleshoot your thermostat here. 


Changing the batteries in your thermostat is not as scary as it sounds. It is actually not that difficult. Follow the instructions in this article and you can change the batteries in your thermostat in no time. This is not something that has to happen often but now you can do it yourself!

For most thermostats, this is a straightforward process that should take less than 15 minutes. Some smart thermostats make it harder to replace the battery. You will need a screwdriver and some patience to get the batteries replaced. If you are not comfortable doing this, you can ask your plumber or electrician to help you out.