Honeywell Thermostat Battery Replacement

The batteries on your Honeywell Thermostat can easily last around a year, but after that, they need a replacement! The good news is you don’t need an expert to replace the batteries if they run flat. Just 5-minutes of your busy schedule, and you can quickly replace the batteries.

How to replace batteries on a Honeywell Thermostat? First, turn off the power, disconnect the live wire, and remove the cover plate. Next, get the old batteries out, and change them with a pair of new AA batteries. Put the cover plate back in place, turn on the thermostat, and you are good to go.

Still, confused and need a detailed explanation for battery replacement on your Honeywell Thermostat? Read on, and you’ll find all the necessary information to do it without any hassles.

General Precautions & Equipment Needed

Before I go ahead with explaining the steps to replace the battery on a Honeywell thermostat, it’s essential to know the general precautions and equipment required. 

General Precautions 

  • Turn off the Thermostat and Remove the Live Wire 

Always turn off the thermostat before removing the baseplate, and remove the live wire carefully. This reduces the risks of any current-related injuries that can be fatal sometimes.

  • Wear Rubber Boots and Gloves

It would be great if you could get a pair of rubber boots and gloves on. You can even use them for other current-related repairs, so it’d be a good investment.

  • Scan the Instruction Manual

Knowing your thermostat better will ease the overall thermostat battery replacement process. Also, you can learn more about the particular thermostat model you’re using.

Equipment Needed

  • A screwdriver (if the cover plate gets jammed)
  • A set of AA  or AAA batteries (for 8000 series)

How to find the Model Number of the Honeywell Thermostat? Is it necessary?

Before changing Honeywell Thermostat’s batteries, you should know about the thermostat model you are using. While most of their models have a similar battery replacement process, there are some models that require a different approach. Here’s how you can find the model number.

  1. Carefully isolate the thermostat’s circuit from the live wire. As your model has batteries, the thermostat could still be on.
  2. Pull/slide the thermostat off the base plate. Some models, including the RTH230B, require you to pull the cover plate gently from the button to get it off.
  3. Note down the model number on the back, and you’ll also find general instructions related to battery information.
  4. Reposition the thermostat, and follow the steps listed below according to the model number you own.

Honeywell Thermostat Battery Replacement: Step-by-step Process

Change Batteries on Honeywell Thermostat 1000, 2000, and 3000 Series

Honeywell’s 1000 and 2000 series is immensely popular among folks on a budget. These thermostats offer ultimate convenience and easy controls, thanks to the built-in LED screen. The particular 1000 and 2000 series include TH1100DV, TH1210DV, TH2110DV, and TH2210DV.

The 3000 series is pretty expensive, as it offers smart features like compressor protection to prolong the life of your appliances. While the model has different features, the process of replacing the batteries is the same as that of the 1000 and 2000 series. The Honeywell Thermostat 3000 Series includes models like TH3110D1008 and TH3210D1004.

  1. Carefully isolate the circuit from the live wire, and turn off the thermostat.
  2. Pull the faceplate gently and remove it from the baseplate. You can now see the batteries.
  3. Remove the old batteries, and install new ones in place. Make sure the battery’s position is correct.
  4. Put the faceplate back in its place, and connect the circuit with the live wire.
  5. Turn on the thermostat, and it’ll back up immediately.

Change Batteries on Honeywell Thermostat 4000 Series

The Series 4000 has improved models and is very popular among homeowners. The thermostat lets you have complete control over the temperature, while you can quickly adjust the emergency heating system. The most famous models of the 4000 series are TH4110D and TH4210D.

  1. Turn the thermostat off, and isolate it from the live wire.
  2. Insert your fingers at the bottom of the cover plate, and pull it outwards.
  3. You can now replace the old batteries with a pair of new AA batteries.
  4. Slide the cover plate back on the base plate, and make sure it fits perfectly.
  5. Turn on the thermostat, reconnect it with the live wire, and you are good to go.

Change Batteries on Honeywell Thermostat 5000 and 6000 Series

Honeywell introduced the 5000 and 6000 series to make your life even more convenient. No struggling with removing the cover plate since these series have a removable battery compartment. Some models of the 5000 and 6000 series are TH5220D, TH5320U, and TH5110D.

  1. Turn the thermostat off. Press and pull the cover plate gently to remove it.
  2. Take the battery compartment off from the top-right corner, and replace the batteries.
  3. Put the cover plate back by sliding it on the base plate, and turn the thermostat on.

Change Batteries on Thermostat 8000 Series 

The Honeywell Thermostat 8000 series models have a big touchscreen and built-in Wi-Fi and come equipped with smart connectivity. This series also offers the Honeywell My Total Connect Comfort, so you can use a mobile app to control the thermostat remotely while being out of the home.

The 8000 series includes models: TH8320U, TH8110U, and TH8321U.

NoteUnlike other models, Honeywell Thermostat 8000 Series models use AAA batteries. 

  1. Turn off the thermostat, and hold the cover plate gently.
  2. Pull it outwards to remove the cover from the base plate.
  3. Remove the old batteries, and install new ones carefully by checking the polarity.
  4. Put the cover plate back, and turn on the thermostat.

Thermostat Sill Not Working After Replacing Batteries. What Should I Do?

In 90% of the cases, the thermostat will be back up as you turn it on. But if it doesn’t work, these could be the possible reasons.

  • You have not installed the batteries in the right orientation.
  • The connection with the live wire is not proper.
  • The faceplate is not seated correctly.

Reinstall the faceplate, check the live wire connection, and reinstall the batteries to make the thermostat work. If nothing helps, it’d be great to seek expert assistance.

How to Find Out if the Thermostat Needs a Battery Replacement?

The Honeywell Thermostat requires a set of batteries to power up the screen. If the display does not work, it could indicate a low battery. Also, some models like the 8000 series give a low battery warning before the screen dies. Note the date of installing fresh batteries, and you can expect them to run flat between 11-12 months.


1. What are the best batteries to use with Honeywell Thermostat?

A: Duracell CopperTop AA Alkaline Batteries are perfect for Honeywell Thermostats. The batteries run longer, so you can have a smooth experience using the thermostat.

2. How do I reset my Honeywell thermostat after changing the battery?

A: Unfortunately, Honeywell thermostats lack a reset feature, causing problems while resetting them. Follow these steps to reset a Honeywell thermostat after replacing the batteries:

  • Power off the thermostat, isolate it from the live wire, and remove the batteries (even if they are fresh).
  • Put the batteries in the wrong orientation after removing the cover plate.
  • Wait for 10-15 seconds, and install the batteries correctly.
  • Your thermostat will be reset to factory settings.

3. Can a Honeywell thermostat work without batteries? 

A: Yes, you can use the Honeywell thermostat without batteries. However, you need to tweak the device for it, which requires changing a few connections. Here’s a detailed video on how to use a thermostat without batteries.

4. What happens when the battery dies in the thermostat? 

A: If the thermostat batteries go flat, it’ll lead to the heating/cooling system stopping, and you’ll see the LED display go black. The only solution is changing the batteries to get all appliances back up.


Now that you know everything about replacing Honeywell thermostat batteries, you can quickly do it whenever required. I recommend keeping the user manual handy so that you know about each part of the thermostat, and it’ll reduce the risks of any damage. Always disconnect the live wire before proceeding with changing the batteries. 

Still, facing issues with your Honeywell thermostat? Drop your problems down in the comments section, and I’ll try to get back to you ASAP with the easiest resort.