One of Home Assistant greatest strengths is its ability to run completely offline. With the right setup, your automations, voice control, and device management work flawlessly even when your ISP has an outage. Here is how to build a truly offline-capable smart home.
What Works Offline by Default
- All local integrations (Zigbee, Z-Wave, local MQTT devices)
- Automations and scripts
- The Home Assistant UI (accessible via local IP address)
- Companion app on devices connected to your local Wi-Fi
- Frigate NVR and local cameras
- Local voice assistants (Wyoming/Whisper)
What Requires Internet (and How to Replace It)
Remote Access
The Nabu Casa cloud subscription requires internet. Solution: use Tailscale — install it on your Home Assistant instance and your phone. Tailscale creates an encrypted tunnel directly between devices. When you are away from home, connect to Tailscale and access Home Assistant as if you were on your local network.
Weather Data
Weather integrations pull data from external APIs. For automations that only need sun position (sunrise/sunset), Home Assistant built-in Sun integration is entirely local.
Voice Assistant
Google Assistant and Alexa require cloud connectivity. Solution: run a fully local voice assistant using the Wyoming integration. Install the Whisper add-on (speech-to-text) and Piper add-on (text-to-speech). Combine with a microphone-equipped device running Wyoming satellite software for a 100% offline voice assistant.
Presence Detection
GPS-based presence detection requires internet on the phone. Solution: use local network presence detection — Home Assistant detects when your phone connects to your Wi-Fi network. This is slightly less precise but works 100% offline.
Configuring Your Router for Maximum Offline Reliability
Consider assigning static IP addresses to all smart home devices, creating a dedicated IoT VLAN for smart home devices, and using local API integrations in Home Assistant rather than cloud integrations where available.
Testing Your Offline Setup
The real test: disconnect your router from the internet and verify that your automations still fire, your lights still respond, and your cameras still record. If everything works, you have built a truly resilient smart home.