Pairing Mysa with Amazon Alexa via Matter

Product: Mysa Smart Thermostat for Central HVAC  |  Firmware: 4.5.37 or later  |  App: Mysa app 4.11 or later

This guide covers pairing your Mysa Smart Thermostat for Central HVAC to Amazon Alexa using Matter, what you can do once it is paired, Alexa voice commands, and Alexa-specific limitations. For an overview of Matter and links to other platforms, see Connecting Your Mysa Smart Thermostat with Matter.

Before You Start

Your thermostat, the phone running the Mysa app, and your Alexa hub must all be on the same Wi-Fi network. If any of these are on a different or guest network, pairing may fail or the thermostat may appear unresponsive.

• Mysa Smart Thermostat for Central HVAC with firmware 4.5.37 or later, online in the Mysa app.

• Mysa app (iOS or Android) 4.11 or later, signed in.

• The Alexa app on an iPhone or Android phone.

• A Matter-compatible Alexa hub — most current Echo speakers, Echo Show displays, and eero routers support Matter. Older Echo (1st/2nd gen) and Echo Dot (3rd gen and earlier) do not. Check the Amazon compatibility list if unsure.

Step 1 — Get Your Matter Pairing Code from the Mysa App

These steps are the same regardless of which platform you are pairing to.

1. Open the Mysa app and tap the menu icon (top left).

2. Under Other, tap Home Assistants.

3. Tap Mysa for Central HVAC, then select your device.

4. On the Connect using Matter screen, tap the Pairing Code field to copy the code, or keep the QR code visible to scan from another device.

Step 2 — Add the Thermostat in Alexa

1. Open the Alexa app and tap Devices.

2. Tap the + button (top right) and choose Add Device.

3. Scroll down and select Other, then choose Matter.

4. Tap Yes on the "Does your device have a Matter logo?" question.

5. Tap Scan QR code and point your phone at the QR code in the Mysa app, or tap Enter setup code to paste the code. Then tap Next.

6. Tap Connect to start connecting to the device.

7. Tap Next after the device connects. Three devices are listed — First device, Thermostat, and First humidity sensor (see below).

8. You can choose to set up these devices or skip.

9. The default name for the thermostat is "Thermostat." Rename it and add it to a room for voice control.

Why Alexa Shows Three Devices

When pairing via Matter, Alexa shows a screen titled "Choose which connected device to set up first" with three options under New Connected Devices:

• First device

• Thermostat

• First humidity sensor

This is normal. Alexa exposes each Matter endpoint separately. First device (or "Second device," etc., if you have multiple Mysa thermostats) is the master record and should not be deleted. Thermostat is where you control your setpoint and modes, and First humidity sensor tracks thermostat humidity. After pairing, rename each device and assign them to the same room in the Alexa app.

What You Can Do in Alexa

Alexa Voice Commands

• "Alexa, set the [device name] to 22 degrees."

• "Alexa, what is the temperature on the [device name]?"

• "Alexa, set the [device name] to heat."

• "Alexa, set the [device name] to cool."

• "Alexa, turn off the [device name]."

Auto Mode and Deadband

Auto mode lets the thermostat switch between heating and cooling based on your "heat to" and "cool to" setpoints. You can enable Auto mode directly from Alexa; when enabled via Matter, a default 2°C deadband applies. Change the deadband (2°C–6°C) only in the Mysa app, and Alexa will honour it.

Alexa Limitations

These come from the Matter standard and Amazon's implementation, not from a defect in your thermostat.

AUX Heat Shows as Heat

When auxiliary / emergency heat is active, Alexa shows the mode as Heat. This is a display difference only. Control AUX / Emergency heat from the Mysa app.

Fan-Only Shows as Off

Fan-only mode shows as Off in Alexa even though the fan is running. This is a display difference only. Control fan-only mode from the Mysa app.

"Turn Off Heat" Voice Command Is Not Supported

Alexa does not support "turn off heat" as a voice command — it will respond that the mode is not supported. Use "Alexa, turn off the [device name]" or change the mode to Off in the Alexa app instead.

May Show Unresponsive Before the Mysa App Shows Offline

After a Wi-Fi drop, Alexa may flag the thermostat as unresponsive before the Mysa app shows it offline. This is normal.

Setpoint Increments

Setpoints work best when adjusted in whole-degree increments. There can be rounding variability at 0.5°C increments. If you prefer a 0.5°C setpoint, set it in the Mysa app and Alexa will honour it, or use an Alexa routine with your preferred value.

Temperature Range Is Narrower Than the Mysa App

Matter platforms support a heat setpoint of 7°C–30°C and a cool setpoint of 16°C–30°C, compared to 5°C–30°C and 16°C–37°C in the Mysa app. Use the Mysa app for the extended range.

Re-Pairing After a Reset

In the Alexa app, go to Devices → your thermostat → Settings → Remove Device before re-pairing. Then generate a new code in the Mysa app and add the device again. Re-pairing in the Mysa app disconnects all Matter platforms and requires recreating routines.