Replace Alexa with a voice assistant that runs entirely in your house
Pull the internet cable out and ask it to turn off the kitchen lights. It still works: Home Assistant hears the wake word on the speaker, Whisper turns your voice into text on your own box, and Piper answers in a British voice. Nothing goes to Amazon, and you tune it until it beats the Echo it replaces.
- Custom commands like "good night" that run whole routines, plus aliases so it understands how you talk
- Optional: a local LLM brain through the Ollama integration for questions beyond home control
- A server for Home Assistant OS: Raspberry Pi 5 4GB kit (around £110 to £150) or an Intel N150 mini PC (around £150 to £200)
- A voice speaker: Home Assistant Voice Preview Edition (around £56) plus a USB-C 5V 2A charger
- Some smart devices already in your home (lights, plugs, heating) or the willingness to add a couple
- For the AI brain (optional): a PC running Ollama, see Run AI on your PC
How a local voice assistant works, and what to buy
Four stages, each one running in your house. Pick hardware that keeps them fast.
Every voice command goes through four stagesAn Echo sends stages 2 to 4 to Amazon. Here, all four stay home:
- 1. Wake word: the speaker listens for "Okay Nabu", "Hey Jarvis" or "Hey Mycroft". On the Voice Preview Edition this runs on the device itself (microWakeWord), so nothing is sent anywhere until you say it.
- 2. Speech-to-text: your sentence goes to the Home Assistant box, where Whisper (any sentence) or Speech-to-Phrase (home control phrases only, very fast) turns it into text.
- 3. Intent: Home Assistant's own conversation agent matches the text to an action: "turn off the kitchen lights" becomes light off in the Kitchen area. Optionally, a local LLM handles anything else.
- 4. Text-to-speech: Piper speaks the reply in a neural voice, including proper British ones.
Pick the server.
- Raspberry Pi 5 (around £110 to £150 with power supply, case and storage): quiet, low power, ideal for home control with Speech-to-Phrase, which Home Assistant says transcribes in under a second even on a Pi 4. Whisper works too, but slower.
- Intel N150 mini PC with 16GB RAM (around £150 to £200): runs Whisper fast enough for free-form sentences and LLM conversations. Home Assistant's docs put Whisper on an Intel NUC at under a second, versus about 8 seconds on a Pi 4.
Pick the speakerThe Home Assistant Voice Preview Edition (around £56 at UK retailers like The Pi Hut) is the easy route: far-field microphones, on-device wake word, a physical mute switch, a 3.5mm output for a better speaker, and a setup wizard. Bring your own USB-C 5V 2A charger. The DIY route is the Espressif ESP32-S3-BOX-3 (around £40 to £50), flashed from ESPHome's ready-made projects page. The parts list has both.
Everything for this mission is in the kit: Download the kit. The benchmark script, the parts list, a ready-made "good night" voice routine, and an Alexa-to-local cheat sheet.