Home Assistant is the most widely used open-source home automation platform in the world, and sooner or later it turns up in any search about smart homes. In this guide we explain exactly what it is, what hardware it needs, which protocols and devices it can integrate, how it differs from cloud platforms and — the question almost nobody answers without a vested interest — when it makes sense to set it up yourself and when you're better off handing it over to an installer.
What is Home Assistant?
Home Assistant (HA) is free, open-source home automation software, created in 2013 by Paulus Schoutsen and now maintained under the Open Home Foundation. It's installed on a small server inside your home and acts as the brain of the installation: it connects devices from different manufacturers and protocols and coordinates them through automations.
Three ideas set it apart from any other platform:
- Local first: automations run on your server, not in a manufacturer's cloud. They keep working even if the internet goes down.
- Open: more than 3,000 official and community integrations. You're not limited to one brand's catalogue.
- Customisable: dashboards, automations and panels adapt to each home or business, from the trivial to the highly complex.
The project releases a new version every month (numbered year.month, e.g. 2026.6), and behind it is one of the most active open-source communities in existence: it's regularly among the repositories with the most contributors on the whole of GitHub.
What hardware you need
Home Assistant needs a machine that stays on 24/7 on your network. The usual options, from simplest to most flexible:
- Home Assistant Green: the official "plug and play" device, for around €100. A convenient way to try the platform without having to decide on hardware.
- Home Assistant Yellow: an official device with a built-in Zigbee/Thread radio.
- Raspberry Pi: the DIY classic and fine for getting started, but no longer the best buy: the SD card ends up getting corrupted over the years (better with an SSD) and, once you add up the accessories, a mini PC gives you considerably more power and reliability for a similar price.
- Mini PC (N100, NUC or similar): the option with the most room to grow, and the one we fit in our own installations: power to spare for cameras, local recognition and years of expansion, for not much more than a Green.
- NAS or virtual machine: if you already have a server at home, HA can live alongside everything else on it.
The recommended operating system is Home Assistant OS, which handles updates and add-ons for you. For the radio protocols (Zigbee, Z-Wave, Thread) you add a USB dongle — the next section shows which one goes with each.
Supported protocols: which is which
Home Assistant's strength is that it speaks all the "languages" of home automation at once. This table sums up the main ones and what each is best at:
| Protocol | How it connects to HA | What it's best at |
|---|---|---|
| Wi-Fi | Your own network, no extra hardware | Plugs, bulbs and relays (Shelly, Sonoff). Careful: dozens of devices can overload a home router. |
| Zigbee | USB dongle + ZHA or Zigbee2MQTT | Battery-powered sensors and a mesh network that gets stronger with every smart plug. 100% local, the workhorse of DIY. |
| Z-Wave | USB dongle + Z-Wave JS | Its own radio band, with no Wi-Fi interference. Very reliable; devices cost a little more. |
| Matter / Thread | Native integration + Thread radio | The new standard backed by Apple, Google and Amazon. Interoperability across ecosystems. |
| Bluetooth | Built into the server, or ESP32 proxies | Temperature sensors, scales, locks close to the server. |
| KNX | KNX/IP gateway, native integration | The professional wired standard in new builds and larger buildings. HA adds a modern layer on top. |
| MQTT | Local broker (official add-on) | The universal bridge: gateways, DIY devices and alternative firmware (Tasmota, ESPHome). |
If you'd like to see these protocols applied to a specific case, our guide to automating your blinds compares Zigbee, Z-Wave and Wi-Fi motors and adapters on the same real-world problem.
Integrations: everything in a single dashboard
With more than 3,000 integrations, Home Assistant brings together things that normally live in separate apps: the robot vacuum, the electric car, the alarm, IP cameras, the speakers and the TV, energy meters, the weather forecast or the family calendar. It also integrates with all three voice assistants (Alexa, Google Assistant and Siri/HomeKit), so you can keep using whichever one you already have.
What's interesting isn't the list, but the fact that everything shares the same automation engine: a single rule can cut across brands — "if the meter detects that the solar panels are producing a surplus, start the dishwasher and charge the car" — something that's impossible when every device lives in its own manufacturer's app.
Local or cloud? The fundamental difference
Consumer platforms (Tuya/Smart Life, Alexa, Google Home) are very easy to get started with, but most of their commands travel to the manufacturer's servers: if your connection drops or the company switches the service off, the automation stops working, and the data on how your home is used gets processed outside it.
Home Assistant turns that model on its head: everything runs and is stored on your server. To access it from outside the house there are two routes: the official Home Assistant Cloud subscription (from Nabu Casa, the company whose revenue funds the project's development) or setting up access yourself with a VPN or a reverse proxy.
To be fair: for a couple of plugs and two bulbs, a cloud app may well be enough. The difference shows as you grow — when the house depends on "everything always working", local control stops being a technical detail. If you want to dig deeper into this approach, we have a guide to cloud-free home automation: what works without the internet, which data stays at home and what it costs.
Advantages and limitations, warts and all
The good:
- Free, with no compulsory fees; the cloud subscription is optional.
- No dependence on any manufacturer: if a brand disappears, your system carries on.
- Real privacy: data on presence, habits and energy use never leaves your network.
- It integrates practically any device and protocol on the market.
- A huge community: almost any problem you run into, someone has already solved.
What nobody tells you:
- The learning curve is real: your first dashboards and automations take hours, not minutes.
- It needs maintenance: monthly updates and, every so often, changes that break some older configuration.
- There's no official paid support: when something fails, the answers are in forums and documentation.
- In the end, reliability depends on the design, not the software: Zigbee mesh coverage, Wi-Fi channels, antenna placement and the quality of the devices you choose.
Set it up yourself or hire an installer?
DIY makes perfect sense if you enjoy the process, your project is contained (a flat, a few rooms), you can live with things failing while you learn and the time you put in is worth it to you as a hobby. Starting with a mini PC or a Raspberry Pi and a few Zigbee sensors is a weekend well spent.
That said, when the installation has to work every single day — not just the day you set it up — design is what makes the difference, and that's where a professional brings what no tutorial covers: sizing the mesh network and the radio coverage so that no sensor is left in a dead zone, choosing Zigbee and Wi-Fi channels that don't tread on each other's toes, picking devices with proven reliability rather than the cheapest thing in the catalogue, installing the relays in the fuse box properly, and configuring the system to recover on its own after a power cut or a network failure. That's what separates a home where it "mostly works" from one where nobody remembers there's any home automation because it simply works.
That's why an installer is especially worthwhile when the project spans many rooms and devices, when you want to integrate the lighting and energy monitoring from the fuse box with professional relays (such as Shelly) with no building work, when it's a business — every hour with the lights or the climate control down costs money — and when the whole family is going to use the system: for anyone who wants nothing to do with technology, stability is non-negotiable. Add to that dashboards designed for non-technical people and someone to call if something goes wrong.
And there's a hybrid route, possible precisely because Home Assistant doesn't lock anyone in: you can start on your own and hand over just the network design or the fuse box work, or the other way round — a professional base installation that you then expand yourself. The server stays in your home and it's yours; any technician (or you yourself) can pick up where someone else left off.
Time for some transparency: we're installers and we work with Home Assistant on residential and business projects — you can see real cases in our projects — so we have a stake in the second option. That's precisely why the criteria above are the same ones we give on a site visit: if your project is small and you fancy learning, do it yourself.
Conclusion
Today, Home Assistant is the most complete platform for anyone who values local control, privacy and the freedom to choose any device: free, with no strings attached and practically unlimited in integrations. The flip side is that reliability doesn't come as standard — it comes from good design and from someone who maintains it, whether that's you, with the time and the will to learn, or a professional. The right decision depends on the size of the project and how much you enjoy the journey, not just the destination.
