Guide to Honeywell Thermostat Battery Replacement 

A blank Honeywell thermostat display might freak you out. However, there’s nothing to panic about, and a quick battery replacement will resolve the issue. 

The replacement steps can differ given the numerous Honeywell Thermostat series, from the older 1000 models to the newest Wi-Fi-equipped versions. 

Guide to Honeywell Thermostat Battery Replacement

Nonetheless, a few troubleshooting steps can help you replace the thermostat battery like a pro, regardless of the series you own. 

Know Your Thermostat’s Model 

Knowing your thermostat’s model number is critical before undertaking a replacement. Popular thermostat models include: 

  • TH 
  • RTH 
  • T
  • CT
  • TL
  • RCHT 
  • RLV 

You can check the thermostat version name through the instruction manual provided by the manufacturer or using your product ID. If you lost the thermostat ID, try pulling the device’s wall plate. 

A few tugs will quickly remove the base plate. However, if you think you’ll damage it, consider getting professional help. 

Once the wall plate comes off, flip it over and read the model’s number on the back. Once you know the thermostat model, purchase the correct battery type for your model. 

Typical batteries are AAA, AA, or lithium-ion batteries. 

An All Model Honeywell Thermostat Battery Replacement Guide 

Replacing a thermostat battery is pretty easy whether you own a new thermostat model or an old one. The key is to determine your thermostat’s model, however. 

Once you know the version you own, you can quickly DIY replace the battery. 

1000 & 2000 Models

Homeowners who seek a budget-friendly thermostat that doesn’t sacrifice quality opt for the 1000 and 2000 series. Numerous multi-family households choose these models because of their optimal functionality. 

Each version features an LED display for easy control. The 1000 series include TH11000DV, TH1210DV, and TH1110DV. 

The 2000 series, on the flip side, include the TH2210DV and TH2110DV models. These series typically need 2 AAA batteries to operate. 

  • Turn off your thermostat and disconnect the circuit as a precautionary measure. 
  • Tug the cover plate from the base to install the new batteries 
  • Now swap the old AAA batteries with the new ones
  • The battery polarity must match the battery compartment markings 
  • Slide the battery cover plate onto the base and fix it
  • That’s it! You have successfully replaced the thermostat battery. Now switch on the thermostat and the circuit. 

3000 Models

The 3000 series include TH3110D1008 and TH3210D1004.  

These models feature built-in compressor protection making them stand out among the other popular versions. This feature protects your AC and heating compressors. Further, it also includes a display screen and a controlling system. 

The 3000 model series might require a yearly replacement. You’ll, however, get a battery alert 2 months before the battery dies completely.  

  • Turn off your thermostat and detach the circuit as a precautionary measure. 
  • Tug the cover plate from the base plate 
  • Place the previously installed batteries with the new ones 
  • Make sure the polarity matches the compartment markings.   
  • Place the cover plate on the base plate and slide it back 
  • Here you go, you have just completed replacing your battery. Turn on your thermostat and test its functioning. 

4000 Models 

This model includes TH4110D and TH4210D. It also features an impeccable control system and a built-in compressor protection system. You can easily set a preferred temperature and adjust the heating system.

This series also includes an LED display that notifies you when the battery drains and displays the indoor temperature, date, time, and more. 

  • Turn off your thermostat and disconnect the circuit breaker as a preventive measure. 
  • Cautiously remove the cover plate from the base plate
  • Replace the worn-out AA batteries with new ones. 
  • Do not forget to match the polarity with the battery compartment markings
  • Slide the cover plate and secure it firmly
  • Turn on the thermostat and check if it’s working. 

5000 Models 

These series include the TH5110D, TH5220D, and TH5320U models. 

If you own the 5000 model, you do not need to tug the battery cover because it features a sliding battery compartment. Instead, sliding the battery slot will do the job. 

This model also has an Auto Changeover feature. So, if you want to use the AC and the heating system on the same day, you can do so with this feature. It automatically shifts between cooling and heating after detecting the temperature. 

  • Turn off your thermostat. 
  • Gently press and pull the cover plate to remove the battery compartment.  
  • Swap the old AA batteries with the newly bought batteries
  • Match the battery polarity with the compartment markings 
  • Place back the cover plate and push it down to secure it 
  • Switch on your thermostat and see how it’s working. 

6000 Models 

The 6000 models include TH6220D, TH6110D, and TH6320U. 

If you own one, lucky for you as it also features a sliding battery slot. However, that’s not the only perk. The 6000 model has some cool hardware upgrades to offer better functionality. 

For instance, it includes a Program Schedule feature, allowing you to set different weekdays and weekend settings. 

It also offers 4 pre-set settings to help you lower the energy costs. 

  • Turn off the thermostat and pull out the cover plate by pressing it gently
  • Remove the battery compartment and replace the old AA batteries 
  • Make sure you install the battery properly by matching the battery polarity to the compartment markings 
  • Slide the plate back to secure it 
  • That’s it! You’ve successfully replaced the batteries in your 6000 thermostat model. 

8000 Models 

The TH8320U, TH8110U, and TH8321U belong to the 8000 series. These thermostats include a touchscreen controller and Wi-Fi. 

It wouldn’t be wrong to say that the 8000 series surpasses the previous models due to these features.

You can control ventilation, humidity, and other settings all from the comfort of your smartphone. 

So, if you’ve mounted your thermostat in your living room, you can operate it from your bedroom without moving out. 

  • Turn the thermostat off. 
  • Pull out the thermostat cover plate. 
  • As soon as the cover plate separates from the base plate, you’ll see 3 AAA batteries.
  • Replace these old batteries with the fresh ones 
  • Do not forget to match the battery polarity with the battery compartment markings. 
  • Place the cover back and turn on your thermostat to check if the blank screen is gone and the functioning is restored. 


The RTH110B might not be programmable or compatible with a heat pump, but it includes other incredible features. For instance, you can use it to control central heating systems, ACs, and hot water systems.  

Besides, it also includes a thermometer that displays the internal temperature. As such, it ensures keeping your room temperature to an optimal degree. 

  • Turn off the thermostat. 
  • Pull off the cover plate. 
  • Take out the old batteries and add the new ones. 
  • Ensure to match the battery polarity with the compartment markings. 
  • Place the cover plate back and press it down to secure it 
  • Turn on your thermostat and check if it’s working fine. 

Lyric Round 

This model has come a long way since its launch. Currently, it features a striking glass display equipping control wheels and buttons. It also includes geofencing technology, allowing you to control the climate per your location. 

This technology helps the thermostat to detect the temperature of the place where your smartphone is located. Next, it sets the HVAC unit temperature accordingly. 

It also works with Apple HomeKit, Apple Watch, and Samsung SmartThings. 

  • Turn off your thermostat and disconnect the circuit as a safety measure 
  • Remove the cover plate of the thermostat to reveal the AAA lithium battery
  • Replace the old one with the new battery 
  • Again, remember to check that the battery polarity matches the battery compartment markings.
  • Place the plate back on the thermostat and press it down firmly 
  • Turn on your thermostat and see if the blank display is gone. Your thermostat should work fine at this point. 


HCW80 functions with HC60NG – a relay module. The thermostat model wirelessly passes the information to the relay module, and the latter works to alter the temperature. 

You can also manually set the temperature if you want. This would require you to use the dial. 

The typical HCW80 model features 2 AA batteries that have extended battery life. Here’s how you can replace the battery if you own this model. 

  • Turn off your thermostat. 
  • Gently press and pull the cover plate to remove it from the base plate 
  • Navigate the AA batteries and pull them off to add the new ones 
  • The battery polarity must match the battery compartment markings for a proper adjustment
  • Slide the cover plate back on top of the base plate 
  • Congratulations! You have successfully changed the thermostat batteries 
  • Turn on your device, and you’re good to go. 

Closing Notes 

A thermostat is an excellent gadget to see the current room temperature and adjust it per your preferences. Besides, you get more advanced functionalities and features with new and varying models on the market. 

But as with any battery-operated appliance, thermostats can run out of power. You’d need to replace the battery at this point. 

We discussed the replacement steps of various thermostat models in the guide. Find yours and take action before the worn-out battery takes a toll on your thermostat compartments. 

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