Honeywell Thermostat E1 Error? – (08 Working Solutions)

Are you getting the Honeywell Thermostat’s E1 error? We will see how to fix it below!

The Honeywell Thermostat will help you keep your house at the correct temperature, but only if you have all the settings right.

Whenever something is wrong, an error code will show up to warn you.

The code E1 means a range of problems, and we will investigate them.

If you are facing an E1 error on your Honeywell Thermostat check the sensor, clean HVAC filters, and assess batteries or wiring. If unresolved, update or reset the device.

There are eight quick solutions that you can put into practice right away!

Honeywell Thermostat E1 Error – Learn 8 Solutions!

Solution #1: Verify The Sensor

The E1 error is most likely related to the sensor.

Since the sensor is another device that sends data to the Thermostat, you will need to assess it individually even though the error code shows up on the Thermostat.

There are a few things you must ensure when verifying the sensor:

• Check if it is clean. When the sensor is not clean enough, it can’t read the temperature correctly. (cleaning instructions are available in solution #5).
• Related to the above, it is a good idea to check the temperature shown on the Thermostat. Then, use another device to confirm if the Thermostat shows the correct temperature.
• Ensure that the sensor is on. Its power feed should be fine. You might want to unplug and plug it again.

The E1 error is simple to fix when the sensor is the issue. All the above should help you, and if you notice that the sensor is defective, you need to replace it.

Solution #2: Clean The System’s Filters

How to fix the E1 error on the heater? That error shows up on the Honeywell thermostat and indicates different possibilities, all of them connected.

If you’ve already checked the sensor and it is fine, next, it is time to check the filter on the air system (heater/AC).

You should clean thoroughly as below.

1. Look for the air filter in the return air duct or HVAC unit.
2. Disassemble it.
3. Check its condition.
4. Clean it as best as possible.
5. If it remains too dirty, you must throw it away.
6. Install the air filter back into the HVAC unit. 

If your air filter remains functional, review its specific cleaning guidelines.

Certain air filters are not suitable for water washing due to their fabric composition.

Upon reactivating the entire system, assess the Thermostat’s responsiveness.

If it fails to respond, consider resetting the circuit breaker once more to ensure it registers the system alteration.

Solution #3: Replace The Batteries

The E1 error sometimes shows up if there is an error with the device’s internal batteries.

Although your Thermostat is hardwired, it counts on batteries that will keep it working should an outage happen.

The batteries might be displaced or damaged, causing the system to alert you for the error.

1. Detach the Thermostat from its mounting.
2. Remove the battery cover.
3. Check the battery’s condition.

If the batteries look fine, simply reposition them and ensure they touch the connecting points correctly.

However, you might verify that the battery’s condition is bad. In such a situation, simply buy a replacement.

Solution #4: Check The Hardwiring

Once you confirm that your Honeywell thermostat’s display is unresponsive, it’s essential to examine the wiring.

Several possibilities could be at play, including damaged wiring, insufficient voltage delivery, or loose connections.

In some cases, subpar wiring may have been used during installation.

Follow these steps:

1. Disassemble the Thermostat.
2. Locate the wiring.
3. Secure any loose connections.

To further diagnose the issue:

1. Use a multimeter.
2. Set it to continuity or 20 VAC.
3. Test the wiring.

Honeywell thermostats require 20 VAC wiring. If the existing wiring can’t meet this requirement, it’s likely the cause of the blank screen.

In this case, replace the inadequate wiring with proper 20 VAC-compatible wiring to resolve the issue.

Solution #5: Clean The Thermostat And Sensor

Is the Honeywell thermostat’s touchscreen showing the E1 error? Over time, your Thermostat can accumulate dirt, potentially affecting its functionality.

Regular cleaning is crucial to maintain its performance.

If it hasn’t been cleaned recently or ever, follow these steps:

1. Gently wipe the Thermostat’s surface with a dry, soft cloth.
2. Use a gentle brush to clean hard-to-reach areas within the Thermostat.
3. Consider using electronics-specific compressed air to remove stubborn debris.
4. After cleaning, ensure there is no residue before reassembling your Thermostat.

Note: Avoid using liquids, as they can harm the system. The only suitable liquid for electronics is isopropyl alcohol.

Solution #6: Eliminate Interference

One further cause of the E1 error is interference all around. The Honeywell thermostat needs a free area to receive data from the sensor.

However, interference from furniture, walls, or devices will make the connection very flimsy.

Here are some tips to improve the data transmissions between the devices:

• Place the sensor and thermostat in a manner that they face each other without objects in between. You must place them a few meters from each other as instructed in the user guide, but keep that tip in mind.
• Don’t let a thick wall stand between the sensor and the Thermostat.
• Reduce the furniture between the devices.
• Check if there are too many smart devices in the same environment. Disconnect some of them from the router or move them to another room and see if that makes a difference.

Solution #7: Update The Thermostat

One good way of eliminating the E1 error is to update the device’s firmware.

The error could be due to the Thermostat being unable to communicate to the network correctly. Once you update the Thermostat, it will have all the tools necessary.

Here is how you can update it through the app:

1. Open the Honeywell Home app.
2. Tap on the menu icon in the top-left corner.
3. Tap on “Settings.”
4. Select the Thermostat that you want to update.
5. Tap on “Check for updates.”
6. If an update is available, tap on “Update“.

Sometimes, however, the update through the app doesn’t affect the Thermostat because there is a connection issue. 

Update Via USB

The Honeywell Vision Pro and Prestige can be updated through the USB port.

To do that, you will need to proceed as follows:

1. Go to the Honeywell site.
2. Look for the section where you can download updates.
3. Download the correct file for your thermostat model (Vision Pro or Prestige).
4. Transfer the update file to a USB flash drive.
5. Connect the USB flash drive to the Thermostat.
6. Turn the Thermostat on.

The Thermostat should recognize the file and prompt you to update the device. If that doesn’t happen, try again. 

Solution #8: Reset The Thermostat

The error E1 might also be due to a deeper error in the firmware.

You can be sure of that if none of the solutions above has solved the issue.

In that case, only a factory reset will work.

Unfortunately, the factory reset will wipe all data out, so you need to set it up from scratch later.

1. Open the app.
2. Select the Thermostat.
3. Tap “Settings.”
4. Choose “Thermostat configuration.”
5. Choose “Delete.”
6. Tap on “Yes.”

Reset Physically

Moreover, you should reset it physically. You can do that in addition to the method above.

Alternatively, you can do that as the only method when the above doesn’t work. 

1. Turn the device off.
2. Take the batteries out.
3. Put the batteries in the inverted way (negative to positive and positive to negative).
4. Leave like that for ten seconds.
5. Remove the batteries and adjust them correctly.
6. Turn the device on again and see if it has been reset.

You don’t need to worry about damaging your Thermostat by putting the batteries in the wrong direction.

Since the device is off, that will not damage it in any way.

It will only send a low-voltage signal to tell the hardware and software that the device must reset.

Quick Recap

Thus, when you get the Honeywell Thermostat’s E1 error, you must proceed by verifying the physical conditions of the device as well as its firmware.

Most of the time, the issue is silly, and the fix is quick. Once you follow all the instructions above, there is no way to go wrong.

More help about Honeywell Thermostats can be found throughout the blog!