A Guide for Unlocking Your Honeywell Thermostat

By Nick Evans •  Last Updated: 11/12/21 •  9 min read

There are many reasons to lock and unlock your Honeywell thermostat. Locking and unlocking your thermostat prevents other people in your home from changing the temperature settings, which can save you money on your utilities. You can also use thermostat locks to help you stick with a schedule and prevent sudden temperature changes. 

That said, there are a few Honeywell thermostats that include this feature. Each model that includes a lock and unlock feature works differently, so it’s important to understand how it works for your specific Honeywell thermostat. Our guide will take you through each model and show you how to lock and unlock your Honeywell thermostat. Read on to learn more about Honeywell thermostats and how the lock and unlock features work.

how to unlock honeywell thermostat

What Is a Lock Mode on Honeywell Thermostats? 

Honeywell Pro series and 8000 series thermostats come with locking features that prevent people without the code from making adjustments to the thermostat. These features operate with a personal identification number (PIN) that users can set. Many Honeywell thermostats with this feature come with a PIN that’s set to 1234. These numbers can be changed.

That said, Honeywell thermostats come with two separate locking options. These options are partial lock and full lock. Both options are useful depending on your needs and schedule.

Partial Lock 

Honeywell thermostats that feature partial lock typically work the same. The partial lock system is designed in a way that gives the user partial access to the unit. While full access is granted with the PIN, the partial lock allows users to make changes to the temperature. You can set the temperature but that’s it with partial lock. 

A partial lock is a great tool for people who don’t have their thermostat on a schedule and prefer to set the temperature manually.

Full Lock 

The full lock feature on Honeywell thermostats completely locks the unit. This means that nothing can be changed until the correct PIN is entered. When the correct PIN is entered the user is granted full functionality until it’s locked again.

The full lock feature is great for people who leave their thermostat on a schedule or people who don’t make frequent changes to temperature settings or general settings.

While there are a few options for locking your Honeywell thermostat, models that come with the locking feature can have it disabled. Therefore, you don’t need to lock your thermostat if you prefer not to.

Read also: How to clean a window AC without removing it

Unlocking and Locking Honeywell Thermostats 

If you have a Honeywell thermostat with locking capabilities it’s important to understand how they work. We’re going to take you through the steps for locking and unlocking Honeywell thermostats that give you the option to do so.

The products we’ll be taking you through are:

We’ll take you through the various steps to lock and unlock each Honeywell thermostat. If you’ve forgotten your PIN, you can follow our instructions down below.

T4 Programmable Thermostat 

The T4 Programmable Thermostat from Honeywell is a well-rounded product that comes with full-lock capabilities. These thermostats can be locked and unlocked with a PIN. The default PIN for these thermostats is 1234. 


Unlocking the T4 Programmable Thermostat is simple. Follow these steps to unlock it:

  1. Find the center button and press “unlock.”
  2. If you haven’t changed the PIN, enter “1234.” If you have changed the PIN, enter your PIN instead. 
  3. Use the +/- symbols to increase or decrease the number until the numbers line up with your PIN.
  4. Repeat the second two steps until the PIN is correctly displayed.

Once the last digit has been selected the thermostat will open automatically.


Locking the Honeywell T4 Programmable Thermostat is easier than unlocking the thermostat. Some thermostats will lock automatically but the T4 thermostat needs to be locked manually.

To do so, follow these steps:

  1. Press the “menu” button.
  2. Find lock and navigate to it by using the + and – symbols.
  3. Select the lock setting.
  4. Confirm your choice.

The Honeywell T4 Programmable Thermostat is one of the company’s more basic locking thermostats. Therefore, you don’t need to worry about complicated features or navigation.

T6 Pro Series Z-Wave Thermostat 

The Honeywell T6 Pro Series Z-Wave Thermostat comes with features for fully locking, partially locking, and unlocking. These features can be used to customize your schedule and prevent other users from changing the temperature in your home.


Unlocking the T6 Pro Series Z-Wave Thermostat is similar to unlocking the T4 Programmable Thermostat. The steps are:

  1. Press the lock symbol on the screen.
  2. Use the + and – buttons to select each digit in your PIN.
  3. If you entered the PIN correctly the thermostat will unlock.

The default PIN for the T6 Pro Series Z-Wave Thermostat is “1234” and PINs are always 4 digits.


If you want to lock the T6 Pro Series Z-Wave Thermostat the steps are even easier. To lock it follow these steps:

  1. Select the “menu” button on the display.
  2. Look for “screen lock” and navigate to it.
  3. Select the “screen lock” option.
  4. Choose between full lock or partial lock.
  5. Press select.
  6. Finalize your settings and confirm your PIN by selecting “yes” when it appears.

We recommend writing your PIN down somewhere so that you don’t forget.

T6 Pro Series Smart Thermostat 

The Honeywell T6 Pro Series Smart Thermostat offers smart capabilities, a big LED display, and many tools to make working with the unit easier. This Honeywell thermostat can be locked and unlocked by using a PIN.


To unlock the T6 Pro Series Smart Thermostat all you need is a PIN. With that number you can follow these steps to unlock your Honeywell thermostat:

  1. Search the menu for the lock symbol and then press it.
  2. Use the + and – symbols to enter the digits of your PIN.
  3. Use the “select” button to confirm your PIN.

When the correct code is entered the device will unlock. If you forgot your PIN you can follow our steps below to recover it.


Locking the Honeywell T6 Pro Series Smart Thermostat is more complicated than unlocking it. That said, you can follow these steps to lock your device:

  1. Press the “menu” button.
  2. Look for “screen lock.”
  3. Select “screen lock.”
  4. Choose between partial and full lock.
  5. Press select.
  6. Finalize your settings and PIN by pressing “yes.”

We recommend writing down your PIN and keeping it somewhere safe. This way you can recover it faster if you forget what it is.

Honeywell 8000 Series Thermostat

Honeywell 8000 Series Thermostats are complex units that come with WIFI and smart capabilities. There are a few units that are part of the Honeywell 8000 series, so it’s important to follow the correct instructions for your device.


There are a handful of Honeywell 8000 series products and the steps for unlocking each model are unique.

To unlock the RTH8500 follow these steps:

  1. Locate the “system” button and hold it down.
  2. Press the blank button in the lower center of the device and hold it until the display changes.
  3. Change the value on the left to your PIN or the default PIN (0670). Use the up or down arrows to change values.
  4. Make the value on the right side 0.
  5. Press done.

If the PIN was entered correctly the device will unlock. The steps to unlock models like the VisionPro TH8321WF or VisionPro models RedLINK, follow these steps:

  1. Press “menu.”
  2. Look for “security settings” on the LED display.
  3. Press the “select” button.
  4. Enter the password or PIN.
  5. Locate and press “done.”


Locking Honeywell 8000 series thermostats is straightforward.

The steps to lock RTH8500 and TH8000 thermostats are:

  1. Press “system” on the LED display
  2. Press and hold the blank buttons in the portion of the device and wait for the display to change.
  3. Change the left values to your PIN or the default PIN (0670).
  4. Change the right value for lock settings. Select “1” (partial lock) or “2” (full lock)
  5. Locate and press “done.”

If everything was done correctly the device will lock. If you have a different Honeywell thermostat like the VisionPro Series TH8321WF or VisionPro with RedLINK the steps are:

  1. Locate the menu button.
  2. Locate the security settings.
  3. Use the arrows to navigate.
  4. Select “change lock mode” or “create a password.”
  5. Create a password if you haven’t.
  6. Press done.

While the process of locking these devices is not the same, the steps are similar and easy to follow for both units.

How to Recover Your Honeywell Thermostat PIN 

PINs for Honeywell thermostats are four-digit numbers that let you lock and unlock Honeywell thermostats. While the PIN is only four digits, it’s easy to forget the PIN, especially if you don’t use it often. The good news is that recovering the PIN for most Honeywell thermostats is easy.

One example is the T4 Pro Model. With the T4 model, the PIN is “1234,” so you can enter that in if you forgot it. If you change the PIN or have a model like the T6  Pro Series, you’ll have to follow these steps to recover it:

  1. Take off the faceplate of the thermostat.
  2. Look for the four-digit code.
  3. You can add 1234 to the four-digit code.
  4. The sum of the numbers is the PIN for the device.

Using these steps you can get back into your Honeywell thermostat, change the PIN, and do whatever else you need to do. If you set a new PIN we always recommend writing it down and storing it somewhere. Doing so will prevent you from losing the PIN in the future.

Lock It Up

Locking and unlocking your thermostat is beneficial for many reasons. It gives users the ability to customize their thermostat experience, set temperature schedules, and prevent other people from touching them. Locking and unlocking your thermostat can also save you time and money depending on how often other users change the temperature.

While many Honeywell thermostats have unique features, the process for locking and unlocking them is similar. Most Honeywell thermostats require a PIN and offer full or partial lock capabilities. Overall, Honeywell is one of the few brands that provide you with the option to make your thermostat unique to your household needs. 

That’s a win in our book.

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