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Operating for over 100 years, Honeywell proudly claims a large portion of the worldwide thermostat market today. Between the entry level 1000 series to the latest Wi-Fi enabled smart round thermostat, there are a wide range of Honeywell devices out there. This can make finding instructions on how to change batteries difficult, as the procedure changes per model. 

Most Honeywell Thermostats have two parts, a base plate, and a cover-plate. The base plate is firmly fixed on the wall, while the cover-plate sits on top of it. 

Generally speaking, to change the battery, you need to turn your thermostat off, and either pull-off the cover-plate or slide out the battery compartment, take out the old batteries and replace them with new ones.

Not all Honeywell Thermostats run on batteries. However, if your model has an LED display, chances are it does! Just like any device that runs on batteries, you need to have these batteries changed from time to time. 

While a minor hassle, there’s no need to panic! With most Honeywell Thermostat models, you need to change the batteries only once a year.

Once you get the “Battery/Batt Low” indicator you will have 60 days to replace the batteries before the device stops functioning.

General Precautions & Equipment Needed

At SmartHomePerfected we always advise readers not to undertake any work they are not competent in performing and if in any doubt, it is best to seek the assistance of a professional.

Some models need AA alkaline batteries, and some require AAA batteries. Before replacing the old ones, make sure you understand how many you need. Also, make sure the battery polarity matches the markings on the battery compartment. Otherwise, you might end up damaging your Thermostat.

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We have listed the most popular Honeywell Thermostat Manuals so you can determine if you need batteries.

If your thermostat has a non-sliding compartment for batteries, you don’t need to panic. To uncover the battery compartment, all you need to do is gently pull the cover-plate off from the bottom, wiggle it if necessary, and it will come right off the base plate. Make sure you cut the electricity before doing this to avoid exposure to living wiring. 

If necessary, you may need to unscrew a small screw at the base before separating. Be careful not to damage the pins or clips when uncovering.

Step by Step – Find Model Number

Before you learn how to change the batteries on your Honeywell Thermostat, you need to know the model you have.

Generally speaking, the model number of your thermostat is either referenced on the front of the device, is accessible through the digital interface or is printed on a label at the back.

Below are steps to perform, if you need to remove the thermostat from the base plate to access the model number.

  1. If the thermostat is mains powered, isolate the circuit to avoid exposure to live wiring. (Once the power is off, the thermostat may still be on as some models have a battery backup)
  2. Carefully slide / pull the thermostat off the base plate, making sure not to damage the pins or clips. In some models, this is accomplished by pulling from the bottom of the device.
  3. Take note of the model number at the back and find the corresponding instructions below.
  4. Reposition the thermostat back on to the base plate

If your Honeywell Model Number is not listed below, then you can search for the user manual for your particular thermostat on the link below to find out how to change the batteries.

Honeywell Thermostat Manuals

Step by Step – 1000 & 2000 Series

Honeywell 1000 and 2000 series are popular among those who are on a budget but don’t want to compromise quality in any way. These two series’ are widely used in multi-family households and apartment complexes.

Each model from these two series’ comes with a LED display for easier control. Whether you intend on using them with your air conditioner or your gas furnace, they’ve got you covered. 

The 1000 series includes models TH1100DV, TH1110DV, TH1210DV, and the 2000 series includes models TH2110DV, and TH2210DV. All the models in these series require 2 AAA batteries.

  1. First, switch off your thermostat and isolate the circuit as a precaution
  2. Gently pull the cover-plate off from the base plate
  3. Replace both AAA batteries with new ones
  4. Make sure the battery polarity matches the markings on the battery compartment
  5. Place the cover-plate back to its place
  6. Slide it onto the base plate until it’s firmly fixed
  7. Congratulations you have successfully changed the batteries
  8. Now you can turn back on your thermostat and circuit

Step by Step – 3000 Series

The built-in compressor protection feature sets this series apart from others. This feature protects the compressors in your air conditioner and heat pump. Moreover, it also hosts a control system and a display screen.

The 3000 series uses batteries to withstand any fluctuations in the AC power supply. Nonetheless, it might need a battery replacement once a year. You will receive an alert 2 months before complete battery depletion.

The 3000 series includes models TH3110D1008 and TH3210D1004.

  1. Switch off your thermostat and isolate the circuit as a precaution
  2. Pull at the bottom of the thermostat to separate the cover-plate from the base plate
  3. Replace its batteries with new ones
  4. Make sure the battery polarity matches the markings on the battery compartment
  5. Slide the cover-plate back on top of the base plate
  6. That’s it. The batteries are changed
  7. You can turn back on your thermostat and circuit. Your thermostat should work fine now

Step by Step – 4000 Series

Just like its predecessors, this series also offers a top-notch control and built-in compressor protection system. Using the control system, you can set your desired temperature, control the fan, and adjust the emergency heating system.

This series comes with an upgraded LED display that will notify you when the battery is running low, the current indoor temperature, the current day & time, and the current system status among others.

This covers models TH4210D & TH4110D

  1. Switch off your thermostat and isolate the circuit as a precaution
  2. To remove the cover plate, place your fingers at the bottom of the thermostat and pull
  3. Replace both the AA batteries with new ones
  4. Make sure the battery polarity matches the markings on the battery compartment
  5. Place the cover-plate back to its place. Slide it onto the base plate until it’s firmly fixed
  6. That’s it. The batteries are changed
  7. You can turn back on your thermostat and circuit. Your thermostat should work fine now

Step by Step – 5000 Series

Are you afraid of electricity? If you have the 5000 series, you don’t need to worry about this at all. This series introduced the sliding battery compartment slot. As a result, to change the battery, you no longer need to separate the cover-plate from the base plate. 

Moreover, this series also came with the Auto Changeover feature. On many occasions, you might need to use both heating and air conditioning on the same day. The Auto Changeover feature makes this possible. It automatically selects between heating or cooling after assessing the indoor temperature.

This covers models Focus Pro, TH5110D, TH5320U & TH5220D

  1. Switch off your thermostat
  2. To remove the battery holder, that sits at the top-right corner, press and gently pull the cover-plate
  3. Take out the battery compartment
  4. Replace both the AA batteries with fresh ones
  5. Make sure the battery polarity matches the markings on the battery compartment
  6. Put the cover-plate back on the base plate
  7. Congratulations. The batteries are changed
  8. Now you can turn back on your thermostat

Step by Step – 6000 Series

This series comes with a sliding battery slot, as well as few other upgrades to the control system from previous models.

Along with hardware upgrades, this series also introduced some software upgrades such as the Program Schedule feature. Using this, you can program different settings for different weekdays and weekends. This feature has four pre-set settings which can greatly help when it comes to energy cost-savings.

This covers models TH6110D, TH6220D & TH6320U

  1. Switch off your thermostat
  2. To remove the battery holder, that sits at the top-right corner, press, and pull the cover plate
  3. Take out the battery compartment
  4. Replace both the AA batteries with new ones
  5. Make sure the battery polarity matches the markings on the battery compartment
  6. Put the cover-plate back on the base plate
  7. Slide it onto the base plate until it’s firmly fixed
  8. Congratulations. The batteries are changed
  9. Now you can turn back on your thermostat

Step by Step – 8000 Series

A complete touchscreen controller and Wi-Fi compatibility are two new feature upgrades in the 8000 series. In short, the 8000 Series underwent a complete revamp that sets it apart from its predecessors. Using these features, you can adjust the humidity, ventilation, program schedule, and other things, just by using your smartphone. 

This series is also compatible with Honeywell’s “My Total Connect Comfort” web portal. It also has an app that allows its users to control their thermostats.

This covers models TH8110U, TH8320U & TH8321U

  1. Switch off your thermostat
  2. Hold the cover-plate with your hand and pull
  3. This will separate the cover-plate from the base plate
  4. Replace all three AAA batteries with fresh new ones
  5. Make sure the battery polarity matches the markings on the battery compartment
  6. Put the cover-plate back on the base plate
  7. Congratulations. The batteries are changed
  8. Now you can turn back on your thermostat

Step by Step – Other (Lyric Round)

Since its first launch in 2014, this model has come a long way. Currently, it offers a large stylish glass display that comes with several buttons and control wheels.  

The Lyric Round is dubbed as the best location-based climate control out there. Some also call it Geofencing. This feature helps Lyric to first assess the temperature of where your phone is located and second to adjust the temperature of your HVAC system accordingly. The Lyric Round is compatible with many third-party products i.e. Apple Watch, Apple HomeKit, Samsung SmartThings among others. Model number RCH9310WF covered below.

  1. Switch off your thermostat
  2. Separate the thermostat from the sub-base
  3. Replace the old AAA Lithium battery with a new one
  4. Make sure the battery polarity matches the markings on the battery compartment
  5. Place the faceplate back on top of the sub-base
  6. Congratulations. Your thermostat is good to go now
  7. Now you can turn back on your thermostat

Step by Step – Other (HCW80)

HCW80 is a room unit that works with HC60NG, which is the relay module. In combination, these two build the set Y6630D1007. HCW80 wirelessly communicates information about room-temperature to the relay module. Afterward, the relay modules make changes to the temperature.

Users can change the temperature manually as well. To do this, they need to use the adjustment dial. This wireless thermostat uses 2 AA batteries that have a battery life of around two years.

  1. Switch off your thermostat
  2. Gently pull the cover-plate to separate it from the base plate
  3. Replace the AA batteries with new ones
  4. Make sure the battery polarity matches the markings on the battery compartment
  5. Place the cover-plate back on top of the base plate
  6. The batteries are changed now
  7. Now you can turn back on your thermostat

Step by Step – Other (RTH110B)

The RTH110B is not compatible with a heat pump. It isn’t programmable either, but it has some top-notch features. This thermostat can be used to control air conditioners, hot water systems, central heating systems, fuel furnaces among others. 

This model comes with a built-in thermometer. The thermometer tells RTH110B the room temperature, which makes it easier for the thermostat to ensure the optimal degrees in your home. This model also notifies you about when you need to replace its battery.

  1. First, switch off your thermostat
  2. Pull the cover-plate, wiggle it and it will come right off
  3. Replace the old batteries with new ones
  4. Make sure the battery polarity matches the markings on the battery compartment
  5. Mount the cover-plate back on top of the base plate
  6. The batteries are changed now
  7. You can now go ahead and turn on your thermostat

Common Honeywell Thermostat Battery Questions

What are the best batteries to use?

Some Honeywell Thermostats use alkaline AA batteries, and some use alkaline AAA ones. If you are not sure which ones your Thermostat requires, check the old batteries already installed on the device. That might give you an idea, or you can also check the user manual for your thermostat model.

One more thing, while changing old batteries, make sure the battery polarity matches the markings on the battery compartment of the thermostat.

How to clear low battery from display after Honeywell Thermostat battery replacement?

Soon after you replace the old batteries, the “Low Battery” sign will automatically disappear. If not, you may need to power down and power up the device to reset it. This may need to be done at the circuit breaker.

Moreover, Honeywell thermostats store your settings into their memory. So even when you dismantle them to insert new batteries, they will remember your settings once they start running again.

Thermostat still won’t work after replacing batteries, what should I do?

It can happen for a couple of reasons. Check if the battery polarity matches the markings on the battery compartment of the thermostat. 

If it matches and your thermostat still doesn’t work, try using the batteries in another device to check if they are draining or not.

If the thermostat still doesn’t work, you should contact the Honeywell Support Team.

What happens when the batteries go dead?

After the “Low Battery” sign starts to flash, you will typically have 60 days to replace the batteries. Your thermostat might also display a blank screen to save energy.

If you still fail to change the batteries, after 60 days they will be depleted of energy and your thermostat will stop functioning.

What is the Honeywell thermostat battery size?

Not all Honeywell thermostats require batteries. But some do, usually the ones with an LED display.

All the thermostats that require batteries need 2 or more alkaline AA or AAA types.

Why is my Honeywell thermostat showing as battery low?

This is how your Honeywell thermostat notifies you about its low-battery-life. The “Battery Low” message is displayed on the LED screen 60 days before its complete depletion.

Conclusion

Well there you go, now you know how to change batteries in your Honeywell Thermostat, starting from the classic Honeywell Thermostat 1000 and 2000 series, to the latest Wi-Fi enabled Round model.

If you’re having difficulty changing batteries on your thermostat or don’t see your model listed above, please leave a comment below. Don’t hesitate. We will get back to you with answers

Sources

https://www.honeywellhome.com

Show CommentsClose Comments

8 Comments

  • Avatar
    Nancy Sullivan
    Posted September 18, 2020 at 3:40 pm

    I have a thermostat that was installed in 2010. It’s 4 1/2″ by 6 ” and is totally LED – no buttons. I have the HVAC system serviced ever year. I don’t know what model it is, and to my knowledge the batteries have never been replaced (if there are batteries). I called the company that installed it and they were not helpful, however, they are willing to come out and check it for $90. If it’s batteries I would like to replace them myself — but I’ve pulled on the cover and it does not easily come off. Any suggestions?

    • Daniel Walsh
      Daniel Walsh
      Posted September 22, 2020 at 2:40 am

      Hi Nancy,

      Without an exact model number, it’s hard to diagnose.

      Is there a particular reason you would like to change the batteries – is the thermostat malfunctioning, LED display off or display showing a low battery sign?

      Some thermostats have backup batteries (which hold your specific heating programming in memory during a power outage), which are typically alkaline batteries.

      Other thermostats are powered directly by alkaline batteries, as opposed to the the heating system.

      Typically alkaline batteries wouldn’t last 10 years with regular use powering an LED display, so if the display is still working fine and there are no “low battery” messages then its possible your model does not have batteries and is powered directly by the heating system.

      Hope this helps!

      D

  • Avatar
    Sarah McIntyre
    Posted September 21, 2020 at 12:19 pm

    I can’t figure out how to open my thermostat to replace batteries. I think my model # is T8400B 1018 (2), or maybe 0330 2C. I don’t even know if my thermostat runs on batteries, but anyway, it isn’t working at all and it’s getting kind of cold in here. The furnace itself is working fine; I know because I have hot water. Please advise.

    • Daniel Walsh
      Daniel Walsh
      Posted September 22, 2020 at 2:29 am

      Hi Sarah,

      The T8400B 1018 isn’t powered by batteries and instead is powered directly through the heating system controls. It also doesn’t have backup batteries, to hold the programming in case of a power outage. I can’t find any specific manuals on 0330 2C so not sure.

      It may be time to call in a heating specialist as there may be a bigger issue to be resolved with the system to get it back up and running.

      Sorry I can’t be more help!

  • Avatar
    Cindy
    Posted October 21, 2020 at 9:11 pm

    I have an old thermostat number T8624D2004N
    9832
    Has blank screen. I have it off the plate piece cant find battery compartment. The N in the number kind of looks like a sideways 2

    • Daniel Walsh
      Daniel Walsh
      Posted October 22, 2020 at 3:08 am

      Hi Cindy,

      We have the user guide and installation manual for that model on our manuals page here – https://www.smarthomeperfected.com/honeywell-thermostat-manuals/

      Essentially that model does not contain batteries and is powered directly from the RH / RC and C wires from the furnace.

      If you have a blank screen, its typically a power issue. It’s best to check if the circuit breaker is tripped and if so reset it. Or the HVAC system fuse may be blown and if so replace it. If your HVAC system has a power switch make sure it is in the On position. The wiring may have become frayed between the furnace and thermostat so you could also check that.

      If none of the above works, its best to follow the troubleshooting guide in the manuals.

      Hope this helps

      Daniel

  • Avatar
    Federico
    Posted October 29, 2020 at 8:16 am

    Can you tell me which current Honeywell thermostats would be a replacement to the old model T874D1165?

    • Daniel Walsh
      Daniel Walsh
      Posted October 29, 2020 at 8:47 am

      Hi Federico

      It looks like the T874 D 1165 is a two-stage heating & cooling thermostat that supports heat pump systems.

      Without understanding the exact heating system and wiring configuration it’s hard to provide a definitive recommendation. The “T6 Pro Smart Thermostat” could work as it supports multi-stage heating and cooling and can be integrated with a heat pump system. However, professional installation is recommended.

      There is a compatibility checker on the T6 Pro product page which would be worth checking to see if it a good replacement – https://www.honeywellhome.com/us/en/products/air/thermostats/wifi-thermostats/t6-pro-smart-thermostat-multi-stage-2-heat-2-cool-th6220wf2006-u/

      You would need to take a look at the existing wiring to see if there is a C-Wire being used. (Might not be as the T874 D 1165 is an analog thermostat) – Most modern thermostats require a C-Wire to provide continuous power to the display. Without a C-Wire, you would either need to install one (Big job), re-use the fan wire, or select a digital thermostat that doesn’t require a C-wire (i.e. one that has batteries)

      Hope this helps

      Daniel

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