Honeywell Thermostat Battery replacement- A Complete Guide to replace All Honeywell Thermostats Model Battery

Honeywell thermostat installed at wall

Honeywell Thermostat has always been my favorite for years, not just because of its long 100 years of history but for the range of thermostats it has given in these years. Starting from the Series 1000 to new smart Wi-Fi enabled thermostats, you can find whatever you want in your budget. But due to its vast models, we are often confused with the right procedure to change batteries as the process changes with the models.

So, how can I change the Honeywell thermostat battery? Generally, you can change the batteries of the Honeywell thermostat by just pulling out the cover plate or just sliding out the battery compartment. Replace the battery and put it as it was earlier.

Now, that you know that changing or replacing the batteries in a Honeywell thermostat is quite easy and even a 10-year-old child can do it but there are few variations in the process with every model out there and therefore, I have come up with the detailed guide on Honeywell thermostat battery replacement same as I posted for Honeywell Thermostat reset for all models.

Before moving further, I would like you to make a note of that all Honeywell thermostats don’t run on batteries and  if you have a Honeywell thermostat having a LED display then you probably have a thermostat running on batteries.

When should you change the Honeywell Thermostat battery?

The battery of a Honeywell thermostat needs to be changed once a year and you will start getting notification for battery replacement 60 days before the battery lasts. Therefore, you get enough time to change the batteries, but is there a catch to this!

The Thermostat has a LED screen that starts showing Low Batt or Replace the battery on the screen. This is the first notification that you get which is probably 60 days before your battery goes down. However, another warning is the black screen and after this warning, your thermostat stops working.

You might have a thermostat that only uses a battery as an extra backup, and you might not be worried about changing the batteries of the thermostat. But believe me, even your thermostat use battery for the backup process but you still need to replace the battery as this might cause certain changes in the Time and Date settings of the Honeywell thermostat.

What battery does Honeywell Thermostat use?

Most of the Honeywell Thermostat models need AAA batteries nowadays, but there are thermostats that need AA batteries. So always make sure what batteries you need before starting the process to change the batteries.

Another catch is that some of the latest thermostats have a sliding battery compartment while others don’t have that, and you need to open the cover plate to change the batteries. For doing this, you can pull the cover plate from thermostat bottom and gently pull it out from the base plate.

You might need to unscrew some screws if needed. Also, make sure to turn off the electricity before you start replacing the batteries so that you might not end off exposing to any living wire.

How to find the model number of the Honeywell Thermostat? Is it necessary?

Since different thermostat models have different processes of battery replacement, you need to know What thermostat model you have at your home? You can check this on the official Honeywell Thermostat websiteOpens in a new tab. o you can even go through the steps mentioned below.

Steps to check the Honeywell Thermostat model number

I have seen that most of the thermostats have the model number printed on the front. However, if your thermostat does not have a model number printed on front of it then you can check in the LED display or you can find it on the back of the thermostat panel.

If you have to find out the thermostat model number from the back, use the below steps.

  • First of all, make sure to disconnect the electricity flow from the circuit. It will protect you from any living wire exposure.
  • Now, slide the thermostat from the bottom to remove it from the base plate.
  • Turn it back and note down the thermostat model number.
  • Now, fix the thermostat to the base place as it was.

Note:- If your thermostat doesn’t have a model number printed on its back then you can check out the same on the user manual provided with the thermostat.

Series 8000 Honeywell Thermostat Battery Replacement- Tested Models TH8110U, TH8320U & TH8321U

The 8000 series of Honeywell Thermostat are one of the best and most advance thermostats having a lot of new features and Wifi compatibility.

You can schedule programs, control humidity, ventilation, and many other features through your smartphone.

The “My Total Connect Comfort” web portal and the Honeywell App can also be used to control the 8000 series Honeywell Thermostat.

  • The first step for battery replacement of all the thermostats is to switch it off.
  • Once, you switch off the Thermostat, open the front cover by holding the base place and pulling out the front cover gently.
  • Replace the batteries (3) with new AAA batteries and make sure to check the + and – polarity of the battery.
  • Now, put the cover back and place it as it was attached to the base plate.
  • The battery replacement is done and now you can switch on the Thermostat.

Series 6000 Honeywell Thermostat Battery Replacement- Tested Models TH6110D, TH6220D & TH6320U

The one of most interesting features of Series 6000 Honeywell Thermostat is Program Schedule Feature. With this, you can schedule feature according to the days which can help save a lot of energy usage.

These thermostats have sliding battery compartment and therefore, the replacement is quite easy.

  • Switch off the Thermostat from the circuit breaker.
  • Press and pull the cover from the bottom to remove the battery holder.
  • Slide out the battery compartment and replace it with AA batteries.
  • Now, put the cover as it was fixed to the base plate earlier.
  • Make sure to check the polarity of the battery before placing the battery compartment.

The battery has been replaced; you can switch on the Thermostat.

Series 5000 Honeywell Thermostat Battery Replacement- Tested Models TH5110D, TH5220D & TH5320U

Series 5000 comes with Auto changeover feature which enables to switch between heating and cooling both by accessing the temperature of the room. The thermostat comes with a sliding battery compartment and you do not have to open the cover from the base plate to replace the battery.
  • Turn off the Thermostat.
  • Just press and pull the cover to take out the battery compartment from the top right corner.
  • Take out the battery compartment and Replace the battery (AA).
  • Now, place the top cover as it was before.
  • You have replaced the battery, its time to switch on the Thermostat.

Series 4000 Honeywell Thermostat Battery Replacement- Tested Models TH4210D & TH4110D

The 4000 Series Honeywell Thermostats come with built in compressor protection system. The controls are also good and can be used to control temperature, fan speed, heating system etc.

The LED display lets you know of the battery condition, temperature, time and date and other important stats.

  • Switch off the Thermostat from the main circuit breaker so that you are not exposed to any live wire.
  • Remove the Cover plate. Push it from bottom.
  • Now, change the batteries (AA) with fresh ones.
  • Put the cover plate back to the base place. Place it firmly.
  • Now that batteries are replaced you can Turn on the Thermostat.

Series 3000 Honeywell Thermostat Battery Replacement- Tested Models TH3110D & TH3210D

The 3000 Series also comes with built in compressor protection and therefore the compressors of the air conditioner and heating pump are always protected.

You need to replace the batteries once a year and the LED display notifies you 60 days before the battery needs to be replaced.

  • Turn the Thermostat Off.
  • Now, push and pull the thermostat cover from the bottom.
  • Once the cover plate is separated from the base plate, replace the batteries.
  • Put the cover back to the base place by sliding it gently until it gets fixed firmly.
  • Turn On the Thermostat.

Series 2000 & 1000 Honeywell Thermostat Battery Replacement- Tested Models TH1100DV, TH1110DV, TH1210DV, TH2110DV & TH2210DV

The 2000 and 1000 series are budget Thermostats from Honeywell. Mostly these thermostats are used in big complexes and apartments.

The thermostats have LED display and can be used with air conditioner and gas furnace.

Overall, if you are on budget and don’t want to compromise on the quality, you can go for the above models.

  • Like all other models, this model also needs to be switched Off first.
  • Now, take out the cover plate from the base plate. You have to pull it from the bottom of the plate.
  • Replace the batteries. It contains 2 AA batteries. Make sure to check the polarity of the battery ( + & -).
  • Put the cover back to the base plate.
  • Now, Switch on the Thermostat.

Some More Thermostats from Honeywell and How to replace their batteries?

Honeywell Thermostat -Model RTH110B

The Model RTH110B can control air conditioners, hot water system and central heating system but misses on some top-notch features like heat pump compatibility and programmability.

This Honeywell model has a thermometer which measures the room temperature and helps in maintaining the temperature of the room.

Replacing the battery

  • Turn off the thermostat.
  • Take out the cover and replace the battery.
  • Make sure to keep the +ve and -ve terminals of the battery right.
  • Put the cover back to the base plate.
  • You have changed the battery successfully. Turn On the Thermostat.

Honeywell Thermostat – Lyric Round (Model Tested RCH9310WF)

The Lyric round Thermostat comes with an amazing feature known as Geofencing. Basically, this feature takes your phone location and control your HVAC temperature accordingly.

The thermostat looks amazing with the full touch glass display having a lot of buttons to adjust temperature and other features.

You can easily connect this thermostat with third party accessories like IFTTT, Apple Watch, SmartThings, HomeKit, Alexa, Google Home etc.

Replacing the battery

  • Make sure to Switch Off the Thermostat and take out the thermostat from the sub-base.
  • Replace the old batteries with the fresh new AAA batteries.
  • Now, place the faceplate back to the sub-base.
  • Turn On the Thermostat.

Frequently Asked Questions on Honeywell Thermostat Battery

What are the best batteries for Honeywell Thermostat? The Honeywell Thermostat use AA or AAA alkaline batteries. You can check your thermostat battery in the user manual, or you can see the old installed batteries.

As far as the battery brands are considered, you can get anyone from Duracell, Panasonic or Kirkland.

What to do if the Thermostat displays Low battery even after the battery replacement? Generally, Low battery notifications goes off automatically once you replace the battery. But, if it is still there then you might have to reset the Honeywell thermostat.

What happens when the thermostat battery becomes dead? The thermostat starts displaying “Low Battery” 60 days before the battery replacement is needed.

The thermostat also goes black screen after some days of low battery display to save the battery power. But if you fail to replace battery within 60 days, the battery becomes dead and then your thermostat stops working.

What is the size of the battery used in Honeywell Thermostat? The Honeywell thermostat either use AA or AAA alkaline batteries. Most of the thermostats that use battery have LED display.

Why does my Honeywell thermostat show Low battery? The Thermostat shows Low Battery 60 days before the battery gets fully depleted to notify you to change the battery ASAP.


This is the site where I share all of the information about home security. I have been working in this industry from last 10 years and therefore, sharing all my experiences and learnings.

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