What Is Home Assistant?
If you have a few "smart" gadgets around the house, you probably also have a few different apps on your phone to run them: one for the lights, one for the thermostat, one for the doorbell, one for the solar system. Home Assistant is a way to bring all of those together in one place, run them from a small computer in your own home, and make them work together automatically.
This page explains what it is in everyday terms. No technical background needed. When a technical word shows up, you'll get a one-line explanation right there.
Home Assistant in one sentence
Home Assistant is free, open-source (the program's code is public, and anyone can inspect or improve it) software that runs on a small computer in your home and acts as a single control center for your smart devices, whatever brand they are.[1]
It is built by a large worldwide community. It is a project of the Open Home Foundation, a non-profit organization, so the project can't be sold or bought out by a company.[1]
What it does, day to day
Once it's set up, most of what Home Assistant does happens quietly in the background. Here are four everyday examples.
Lights on at sunset
Home Assistant knows when the sun sets at your location each day, so the porch and living-room lights come on by themselves, even as sunset moves earlier in winter and later in summer. No timers to reset.[3]
Door-left-open alert
A small sensor on the garage or back door tells Home Assistant whether it's open. If the door has been open for, say, ten minutes, your phone gets a message: "The garage door is still open."[1]
Solar and battery dashboard
One screen shows how much power your solar panels made today, how full the home battery is, and how much you pulled from or sent back to the grid. You can also track gas and water.[4]
Behind each of these is an automation: a simple rule in the form "when this happens, and if this is true, then do that." Home Assistant lets you build these by picking options from menus, with no programming.[3] For example: when the sun sets, and if someone is home, then turn on the porch light.
It also gives you a dashboard (a screen of buttons, switches and readings you arrange yourself) that you can open on a phone, a tablet or any web browser in the house.[1]
Why use it instead of each company's app?
One app for many brands
Most smart devices come with their own app, and those apps rarely talk to each other. Home Assistant works with devices and services from over a thousand brands.[1] It brings them into one app, so a door sensor from one company can turn on a light from another. When it starts up, it even scans your home network and offers to add the devices it recognizes.[1]
Local control
Local control means your devices are controlled by a computer inside your home instead of by a company's servers on the internet. Home Assistant talks to devices locally whenever it can and uses the internet only when a device gives it no other choice.[1] In practice, that means your lights and automations keep working when the internet goes down,[2] and switching something on happens right away, with no trip to the cloud and back.
Privacy
Your smart-home history (when doors open, when people come and go, how much power you use) stays on your own computer. Home Assistant does not store your data in the cloud.[1] Even the phone app sends your location straight to your own Home Assistant, not to a third party.[1]
No lock-in
Because it works across brands, you can pick each device on its own merits instead of staying with one company. If a manufacturer drops a product or changes its app, the rest of your home keeps running.
Being honest about the trade-offs. Home Assistant asks for more of you up front than a single-brand app does. You set it up yourself, and you'll spend some time adding devices and building automations the way you like them. Some devices can only be reached through their maker's cloud service, so those still need the internet. To reach your home from away, you either set up remote access yourself or use the optional paid Home Assistant Cloud service.[6] For most people the reward is a home that works the way they want, but it's a hobby-sized project, not a five-minute one.
A few words you'll see
- Integration
- A connector that lets Home Assistant talk to one brand of device or one online service, for example a particular brand of smart bulb.[3]
- Device and entity
- A device is the physical thing (a motion sensor). Its entities are the separate readings or controls it offers (motion, temperature, light level).[3]
- Area
- A room or space you group devices into, such as "Kitchen", so you can say "turn off the kitchen" instead of naming every light.[3]
- Automation
- A rule that runs by itself: when something happens, check a condition, then do something.[3]
- Scene
- A saved "mood" for several devices at once, such as "Movie night": lights dimmed, TV on.[3]
- App
- Extra programs that run alongside Home Assistant on the same computer, such as a file-sharing tool. These were called "add-ons" until early 2026.[3][7]
- Companion app
- The official Home Assistant app for iPhone and Android. It shows your dashboards, receives alerts, and can tell Home Assistant when you leave or arrive home.[1]
What you need to get started
Home Assistant needs a small computer that stays on all the time and is plugged into your home network. You have three common choices:[2]
| Option | What it is | Good for |
|---|---|---|
| Home Assistant Green | A small box sold with Home Assistant already installed. You plug in power and a network cable and you're running. | The easiest start. No assembly, no installing. |
| Raspberry Pi | A credit-card-sized computer. Home Assistant supports the Raspberry Pi 4 and Raspberry Pi 5 with at least 2 GB of memory. | People who like a small do-it-yourself project. See the step-by-step guide linked below. |
| A computer you already have | An older PC or a computer that can run a virtual machine (a "computer inside a computer" program). | Those comfortable with a bit more setup. |
Beyond the computer itself, you'll want:
- Your home internet router with a free network port and a network cable. A wired connection is required for installation and recommended afterwards.[8]
- A phone, tablet or computer with a web browser for setting things up. All the setup happens in the browser, with no typing of commands.[9]
- The smart devices you already own. Many are found automatically. You don't need to buy anything new to begin.
- The free Companion app on your phone, for alerts and control when you're out.
- Later, maybe: a small USB radio for device families such as Zigbee, Thread or Z-Wave (low-power wireless "languages" many sensors and bulbs use instead of Wi-Fi). Home Assistant has its own official ones, the Connect ZBT-2 and Connect ZWA-2.[1]
Plan on an afternoon for the first setup, then add devices and automations a little at a time.
Next: Setting Up Home Assistant on a Raspberry Pi →A step-by-step guide with a shopping list, installation, first setup, backups and updates.
Sources
- Home Assistant home page, features and project overview: https://www.home-assistant.io/
- Home Assistant, "Installation": https://www.home-assistant.io/installation/
- Home Assistant, "Concepts and terminology": https://www.home-assistant.io/getting-started/concepts-terminology/
- Home Assistant, "Home energy management": https://www.home-assistant.io/docs/energy/
- Home Assistant, "Assist" voice control: https://www.home-assistant.io/voice_control/
- Home Assistant, "Home Assistant Cloud": https://www.home-assistant.io/cloud/
- Home Assistant release notes, "2026.2: Add-ons are now called Apps": https://www.home-assistant.io/blog/2026/02/04/release-20262/
- Home Assistant, "Raspberry Pi" installation: https://www.home-assistant.io/installation/raspberrypi/
- Home Assistant, "Onboarding Home Assistant": https://www.home-assistant.io/getting-started/onboarding/