Amazon Smart Thermostat Not Connecting to Wi-Fi or Alexa: How to Fix It

The Short Answer

Two router settings cause most of these. Amazon says the thermostat “requires 2.4 GHz Wi-Fi to operate; 5 GHz Wi-Fi isn’t compatible”, and that the WPA3 security setting should be turned off on your router. Check those before you reset anything.

1. Make sure the router is broadcasting 2.4 GHz and WPA3 is off.
2. Update the Alexa app, then check which network the thermostat is on.
3. Reboot the router.
4. Re-enter the Wi-Fi details in the Alexa app.
5. Remove the thermostat from the app and reinstall with a partial reset; only then a full reset.

1. Router Settings: 2.4 GHz and WPA3

• 2.4 GHz only. If your router combines 2.4 and 5 GHz under one name and the thermostat will not join, look in the router settings for a way to enable or separate the 2.4 GHz band.
• WPA3 off. Amazon says to make sure WPA3 is turned off. On eero routers the setting is on the device settings page; for other routers Amazon says to ask the manufacturer. WPA2 is the setting to use instead.
• Changed your Wi-Fi name or password? The thermostat still has the old one. Go to step 3 below.

2. Check the Network in the Alexa App

Amazon’s connectivity check: open the Alexa app, go to Devices, select the thermostat, tap the gear, and look under Wi-Fi Network. If the wrong network is listed, tap Change. If the right one is listed and it is still offline, check the router with another device: if your phone has no internet on that network either, the thermostat is not the problem. Amazon also says to update the Alexa app from your app store and that rebooting the router can help.

3. Re-enter the Wi-Fi Settings

To put the thermostat on a new network or re-enter the password, Amazon’s path is: Devices → Thermostat → your thermostat → Device Settings → Thermostat configuration → Wi-Fi, then follow the on-screen instructions.

4. Stuck on “SEt” With a Blinking Yellow Light

During setup, Amazon says a display showing SEt with a blinking yellow light may mean the thermostat needs to install updates first. Give it some time. To force the update, pull the faceplate off, wait 30 seconds and put it back, then close and reopen the Alexa app. If the app says installation failed, try the install again.

5. Partial Reset, Then Full Reset

If it still will not connect, Amazon’s next step is to remove the thermostat from the Alexa app and reinstall it with a partial reset, which keeps your HVAC wiring settings. Only if that fails does Amazon suggest removing it and reinstalling with a full factory reset.

Step-by-step for both is in how to reset an Amazon Smart Thermostat.

If It Connects but Keeps Going Offline

A thermostat that drops off Wi-Fi at random, especially when the heat or air conditioning starts, may be losing power rather than signal. This model has no battery and needs a solid C wire. See does the Amazon Smart Thermostat need a C-wire? and Amazon Smart Thermostat blank screen.

Frequently Asked Questions

Why won’t my Amazon Smart Thermostat connect to Wi-Fi?

Amazon says it needs 2.4 GHz Wi-Fi (5 GHz is not compatible) and that WPA3 should be turned off on the router. Then update the Alexa app, reboot the router and re-enter the Wi-Fi settings.

Does the Amazon Smart Thermostat work on 5 GHz Wi-Fi?

No. Amazon says the thermostat requires 2.4 GHz Wi-Fi and that 5 GHz is not compatible.

How do I change the Wi-Fi on my Amazon Smart Thermostat?

In the Alexa app: Devices, Thermostat, select your thermostat, Device Settings, Thermostat configuration, Wi-Fi, then follow the instructions.

Should I factory reset my Amazon Smart Thermostat if it is offline?

Not first. Amazon suggests removing it from the Alexa app and reinstalling with a partial reset, which keeps the HVAC settings, and a full factory reset only if that fails.

Related Guides

• How to reset an Amazon Smart Thermostat — partial and full reset steps
• Amazon Smart Thermostat blank screen — when it has no power
• Does it need a C-wire? — the usual cause of dropouts
• Smart thermostat troubleshooting — every fix guide by symptom

Sources

• Amazon: Smart Thermostat installation isn’t working
• Amazon: Update the Wi-Fi settings on your Smart Thermostat
• Amazon: Checking Wi-Fi connectivity on smart home devices
• Amazon: Partial reset
• Amazon: Full factory reset