How to Change the Battery in a Honeywell Thermostat

November 6, 2023
A pile of batteries

A well-functioning thermostat is the unsung hero of home comfort, quietly ensuring your living spaces remain at the ideal temperature. However, even the most reliable Honeywell thermostats require occasional battery changes to operate efficiently. Given the variety of Honeywell models on the market, each with its own instructions, a comprehensive guide is essential. This article will walk you through the steps to change the battery in your Honeywell thermostat successfully.


Before diving into the battery replacement process, ensure you have the necessary tools and materials. You’ll typically need a set of fresh AAA or AA batteries, depending on your Honeywell model, and possibly a Phillips screwdriver. Safety should be your top priority; always turn off the thermostat and, if possible, disconnect it from the main electrical supply to avoid any risk of electric shock. Some models may also require you to remove the device from its wall mount, so exercise caution to avoid damaging the wires connected to the thermostat.

Identifying Your Honeywell Thermostat Model

Knowing the specific model of your Honeywell thermostat is crucial for a smooth and successful battery replacement process. Different models may have varying battery types, compartment locations, and removal methods. Therefore, identifying your model ensures you follow the correct procedure and use the appropriate materials.

Finding the Model Number

To find your thermostat’s model number, you can usually locate it printed on the front of the device. If it’s not visible there, you may need to check the LED display or look at the back of the thermostat panel. Sometimes, you may have to remove the thermostat from its wall mount to find the model number. Always turn off the electricity before doing so to avoid any safety risks.

How Your Model Number Affects the Process

Understanding your model number is not just about knowing which batteries to buy; it’s also about understanding the nuances in the replacement process for that specific model. Some models may require additional steps or precautions, making it essential to identify your thermostat model beforehand.

General Steps for Honeywell Battery Replacement

Changing the battery in a Honeywell thermostat generally involves a series of straightforward steps, but the specifics can vary depending on whether you have a programmable or non-programmable model. Here’s a high-level overview to give you an idea of what to expect:

  1. Turn off the thermostat and disconnect it from the electrical supply for safety.
  2. Locate the battery compartment. This is often on the side or back of the unit.
  3. Remove the battery compartment cover or the entire faceplate, depending on the model.
  4. Take out the old batteries and dispose of them properly.
  5. Insert the new batteries, paying attention to the polarity.
  6. Replace the cover or faceplate.
  7. Turn the thermostat back on and check for proper functioning.

Battery Replacement for Programmable Honeywell Thermostats

  1. Gently pull the lower right corner of the thermostat to loosen it.
  2. Separate the cover from the body while keeping the body attached to the wall.
  3. Replace the batteries, usually AAA, ensuring correct polarity.
  4. Snap the cover back into place.

Battery Replacement for Non-Programmable Honeywell Thermostats

  1. Hook your finger underneath the outer plastic ring and pull it towards you.
  2. This will give you access to the inner components.
  3. Replace the batteries, often AA, ensuring you match the polarity correctly.
  4. Push the outer ring back into place.

Model-Specific Guides

While the general steps for replacing a Honeywell thermostat battery are similar across models, some nuances can make each model’s process unique. Below are detailed guides for some of the most common Honeywell thermostat series.

Series 8000

The Series 8000 thermostats are advanced models with features like Wi-Fi compatibility and humidity control.

  1. Turn off the thermostat.
  2. Open the front cover by holding the base plate and pulling out the front cover gently.
  3. Replace the old AAA batteries, ensuring correct polarity.
  4. Replace the front cover and turn the thermostat back on.

Series 6000

Known for their program scheduling features, these models generally have a sliding battery compartment.

  1. Switch off the thermostat from the circuit breaker.
  2. Press and pull the cover from the bottom to remove the battery holder.
  3. Replace with new AA batteries, ensuring correct polarity.
  4. Replace the cover.

Series 5000

These models come with an auto changeover feature and a sliding battery compartment.

  1. Turn off the thermostat.
  2. Press the cover to remove the battery compartment from the top right corner.
  3. Replace the AA batteries.
  4. Replace the top cover and turn the thermostat back on.

Series 4000

These models come with a built-in compressor protection system and an LED display.

  1. Turn off the thermostat from the main circuit breaker.
  2. Remove the cover plate by pushing it from the bottom.
  3. Replace the AA batteries.
  4. Replace the cover plate and turn the thermostat back on.

Series 3000

These models also come with built-in compressor protection.

  1. Turn off the thermostat.
  2. Push and pull the thermostat cover from the bottom.
  3. Replace the batteries.
  4. Replace the cover and turn the thermostat back on.

Series 2000 & 1000

These are budget-friendly models commonly used in large complexes.

  1. Turn off the thermostat.
  2. Pull the cover plate from the bottom of the plate.
  3. Replace the 2 AA batteries, ensuring correct polarity.
  4. Replace the cover and turn the thermostat back on.

Model RTH110B

This model can control air conditioners, hot water systems, and central heating but lacks some advanced features.

  1. Turn off the thermostat.
  2. Remove the cover and replace the battery.
  3. Ensure the terminals of the battery are correctly oriented.
  4. Replace the cover and turn the thermostat back on.

Lyric Round Model

This model comes with features like Geofencing and a full-touch glass display.

  1. Turn off the thermostat and remove it from the sub-base.
  2. Replace the old AAA batteries.
  3. Replace the faceplate with the sub-base.
  4. Turn the thermostat back on.

Each of these model-specific guides aims to provide you with the most accurate and helpful information for changing the battery in your Honeywell thermostat. Always consult your user manual for additional steps or precautions unique to your model.

Why Change the Battery?

The lifespan of batteries in Honeywell thermostats typically ranges from eight months to a year, depending on the model and usage. Most Honeywell thermostats have a low battery indicator light or display a “Low Batt” message, giving you about 60 days to replace the batteries. Ignoring these signs can lead to more than just an uncomfortable home temperature. A dead battery could result in the loss of your customized settings and, in some cases, may even cause the thermostat to malfunction. Timely battery replacement is crucial for maintaining both comfort and functionality.


Even with the best intentions, you may encounter issues after replacing your Honeywell thermostat’s battery. If your thermostat doesn’t power up or function correctly post-replacement, here are some common troubleshooting steps:

  • Check Polarity: Ensure the batteries are inserted with the correct polarity. Reversing the polarity can prevent the thermostat from turning on.
  • Reset the Thermostat: Some models require a system reset after battery replacement. Consult your user manual for specific reset instructions.
  • Check for Corrosion: Inspect the battery terminals for any signs of corrosion or damage, which can affect performance.
  • Firmware Update: For smart thermostats, ensure your firmware is up-to-date.
  • Consult User Manual: When in doubt, always refer to the manual or contact Honeywell’s customer support for model-specific guidance.

By systematically addressing these issues, you can resolve most post-replacement problems and ensure your thermostat functions optimally.

Frequently Asked Questions

Q. What type of batteries do Honeywell thermostats use?

The type of batteries required for Honeywell thermostats varies by model. However, the most commonly used are AA or AAA alkaline batteries. Some advanced models may use lithium batteries for longer life. Always consult your user manual for specific battery requirements.

Q. How do you reset the low battery notification?

After replacing the batteries, the low battery notification should disappear automatically. If it doesn’t, you may need to reset your thermostat. This usually involves pressing a specific combination of buttons, which can be found in your user manual. Some models may require navigating the settings menu to reset the notification.

Q. What happens when the thermostat battery dies?

A completely dead battery can result in several issues. Your thermostat will lose its programmed settings, and in some cases, it may stop functioning altogether, affecting your home’s heating or cooling systems. Some advanced models have a backup power source that kicks in to preserve settings, but it’s best not to rely on this feature.

Honeywell Battery Replacement: Final Thoughts

Changing the battery in your Honeywell thermostat is a straightforward yet crucial task for maintaining a comfortable and energy-efficient home. Whether you have a programmable or non-programmable model, timely battery replacement ensures uninterrupted performance and preserves your customized settings. We’ve covered everything from general steps to model-specific guides and troubleshooting tips. Don’t wait for your thermostat to fail; take proactive steps now to replace the battery and ensure your home remains a haven of comfort.

Carney & Son Air Conditioning and Heating

Carney & Son, 72 Degrees

We are a family Owned & Operated HVAC Services in Charleston, SC, proudly serving the Charleston community for 39 years.

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