Nest Matters

A Home Assistant integration that combines Google Nest and Matter thermostat entities into a unified climate control interface. This integration provides the best of both worlds: responsive temperature control via Matter (no rate limits) and full HVAC/fan features via Google Nest.

Features

• Unified Climate Entity: Single interface combining Matter and Google Nest thermostats
• Intelligent Routing: Temperature changes via Matter (fast, no rate limits), HVAC/fan control via Google Nest (full features)
• Auto-Discovery: Automatically finds and pairs Matter + Google Nest thermostat combinations
• Web UI Configuration: Easy setup through Home Assistant UI, no YAML required
• Real-time Updates: Responsive temperature readings from Matter integration
• Full Feature Support: Access to all HVAC modes, fan controls, and humidity readings

Prerequisites

1. Home Assistant

• Home Assistant 2026.2.1 or newer is required.

2. Google Nest Integration

The Google Nest integration must be configured and your thermostat added to Home Assistant.

3. Matter Integration

The Matter integration must be enabled in Home Assistant.

4. Supported Hardware

• Google Nest Learning Thermostat (4th Generation) - This is the only supported model as it's the only Nest thermostat with Matter support.

Setup Instructions

Step 1: Enable Matter on Your Thermostat

1. On your Nest thermostat, navigate to:
   • Settings → Matter → Link Another App → Enter Manually
2. This will display a Matter pairing code
3. Use this code to add the thermostat to Home Assistant via the Matter integration

Step 2: Configure Entity Names (Important!)

For auto-discovery to work properly, you need to rename your Matter thermostat entity:

1. Go to Settings → Devices & Services → Entities
2. Find your Matter thermostat entity
3. Click on the entity and select "Generate new entity ID"
4. Rename the thermostat so the Matter entity name follows this pattern:
   • Google Nest entity: climate.living_room
   • Matter entity: climate.living_room_matter

Note: The Matter entity name must be the same as the Google Nest entity name plus _matter suffix for auto-discovery to work.

Step 3: Install Nest Matters

Via HACS (Recommended)

Manual Installation

1. Download the latest release from GitHub
2. Extract the nest_matters folder to your custom_components directory
3. Restart Home Assistant

Step 4: Configure the Integration

1. Go to Settings → Devices & Services
2. Click "+ Add Integration"
3. Search for "Nest Matters"
4. Follow the setup wizard:
   • If auto-discovery finds your thermostat pairs, select the one you want to configure
   • If auto-discovery doesn't work, choose manual configuration and select your Matter and Google Nest entities

How It Works

The integration creates a unified climate entity that intelligently routes commands to the appropriate underlying entity. The entity is push-based — it subscribes to state change events from both source entities and updates instantly, with no polling.

Each unified thermostat appears as a proper device in the Home Assistant device registry.

Temperature Control → Matter Entity

• Why: Matter operates locally with no rate limits and provides faster response
• Used for: Setting target temperature, reading current temperature

HVAC & Fan Control → Google Nest Entity

• Why: Google Nest integration provides full feature access
• Used for: Changing HVAC modes (heat, cool, auto), fan settings, turn on/off, accessing humidity data

State Display

• Current Temperature: From Matter entity (local, more responsive)
• Target Temperature: From Matter entity
• HVAC Mode: From Google Nest entity
• Fan Mode: From Google Nest entity
• Humidity: From Google Nest entity

Configuration Options

Auto-Discovery

If your entities are named correctly (e.g., climate.living_room and climate.living_room_matter), the integration will automatically discover available pairs during setup.

Manual Configuration

If auto-discovery doesn't work, you can manually select:

• Integration Name: Display name for the unified entity
• Matter Entity: Your Matter thermostat entity
• Google Nest Entity: Your Google Nest thermostat entity

Troubleshooting

Auto-Discovery Not Working

1. Check that your Matter entity name ends with _matter
2. Ensure both entities are available and not in an error state
3. Verify entity names match the pattern: climate.room_name and climate.room_name_matter

Entity Unavailable

1. Check that both the Google Nest and Matter integrations are working properly
2. Verify your thermostat is online and accessible
3. Check Home Assistant logs for any error messages

Temperature Changes Not Working

1. Verify the Matter entity is responding to temperature changes
2. Check that the Matter integration is properly connected
3. Ensure the thermostat is not in an error state

Matter Entities Unavailable (Proxmox Users)

If your Matter entities are constantly unavailable while the Google Nest entities work fine, and you see Unable to establish CASE session errors in the Matter server logs — this is almost certainly caused by multicast snooping on the Proxmox bridge.

Symptoms:

• Matter server discovers devices via mDNS but CASE sessions always time out
• All Matter nodes fail simultaneously
• Google Nest (cloud) integration works fine for the same devices

Cause: With multicast snooping enabled, the Proxmox bridge filters IPv6 Neighbor Discovery packets, preventing the Matter server from establishing direct connections to devices — even though mDNS discovery (multicast) still works.

Fix: Disable multicast snooping on the bridge. On the Proxmox host:

# Immediate (non-persistent)
echo 0 > /sys/devices/virtual/net/vmbr0/bridge/multicast_snooping

Then restart the Matter integration in HA. If Matter recovers, make it persistent by adding bridge-mcsnoop 0 to your bridge config in /etc/network/interfaces:

auto vmbr0
iface vmbr0 inet static
    ...
    bridge-ports <your-interface>
    bridge-stp off
    bridge-fd 0
    bridge-mcsnoop 0

Note: Disabling multicast snooping makes the bridge forward multicast to all ports (like broadcast). On a typical home Proxmox setup with a handful of VMs, the extra traffic is negligible. The setting is also instantly reversible: echo 1 > /sys/devices/virtual/net/vmbr0/bridge/multicast_snooping

Advanced Usage

Multiple Thermostats

You can set up multiple Nest Matters entities if you have multiple thermostats. Each thermostat pair will create its own unified entity.

Automation Integration

The unified entity works with all Home Assistant automation features:

automation:
  - alias: "Morning Temperature"
    trigger:
      platform: time
      at: "07:00:00"
    action:
      service: climate.set_temperature
      target:
        entity_id: climate.living_room_unified
      data:
        temperature: 22

Support

• Issues: GitHub Issues
• Documentation: GitHub Repository
• Home Assistant Community: Community Forum

License

This project is licensed under the MIT License - see the LICENSE.md file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Changelog

See CHANGELOG.md for a list of changes and updates.