Home Assistant Software Explained 2026: Free Open-Source Automation, UK Energy Savings and the Hardware That Runs It

For British households on an Octopus Agile or Intelligent tariff, Home Assistant software does something no commercial hub does out of the box: it reads your live electricity rates and switches the heavy loads — the EV charger, the immersion heater, the home battery — into the cheapest half-hours of the day. That single trick, enabled by a native Octopus Energy integration, is why UK buyers increasingly end up here rather than in a closed ecosystem.

The software itself costs nothing. Home Assistant is open source under an Apache 2.0 licence and is maintained by Nabu Casa alongside a very large volunteer community. It runs on your own hardware, keeps working when the cloud goes down, and pulls Zigbee, Z-Wave, Matter, Thread, Wi-Fi, Bluetooth and cloud APIs into one local dashboard. What it costs is hardware, and — optionally — a cloud subscription. This guide covers both, plus where Home Assistant still falls short against the likes of Homey Pro and Hubitat Elevation. Everything below is drawn from manufacturer specifications, the project’s own documentation and aggregated owner feedback, not from hands-on lab testing.

Quick picks

What Home Assistant software actually is

Home Assistant is a home automation platform that acts as the brain of a smart home. Rather than controlling one brand’s devices through that brand’s app, it exposes everything — a Philips Hue bulb, an IKEA TRÅDFRI sensor, a Shelly relay — inside a single interface and runs your automations on hardware you own. That is the whole pitch: automations keep working when the broadband drops, when a manufacturer shuts down its cloud, or when a subscription lapses.

The software is free; the cloud subscription is optional

The platform costs £0 to download and run. Nabu Casa’s optional Home Assistant Cloud subscription is listed at approximately £5 a month, and it exists to solve two specific problems: voice control through Alexa and Google Assistant, and secure remote access to your dashboard without opening ports on your router. You can self-host both features, but the subscription removes the port-forwarding and certificate work. Because the price is billed in local currency with VAT, check nabu-casa.com for the current GBP figure rather than relying on the number above.

Release cadence and integration coverage

New versions ship monthly, on the 2026.x series, with the current release number published at home-assistant.io/blog. Monthly releases matter because they carry both new device support and security fixes — which is one reason the install method you choose (below) has real consequences.

The official integrations index at home-assistant.io/integrations lists well over 3,000 integrations as of recent counts. Importantly, Home Assistant does not divide the world into “official” and “unofficial”. Integrations are graded on a quality scale — Gold, Silver, Bronze, Internal and Virtual — so a Bronze integration may work perfectly well but lack the documentation, automated testing and active maintainer commitment of a Gold one. Check the grade before you buy hardware on the strength of an integration listing.

The four ways to install it — and why the choice matters

The distinction that catches people out is add-ons. HAOS — Home Assistant OS — is the full appliance experience: it includes the add-on store and one-click updates, and it is what Green and Yellow run. Losing add-ons means losing the one-click installs for things like Zigbee2MQTT, the Whisper speech-to-text engine and MQTT brokers you would otherwise add in a couple of clicks.

Supervised runs HAOS on top of an existing Debian installation, which gives more control at the cost of more ways to break things, and updates are only partially automatic. Container is a Docker container without Supervisor, popular on Synology and QNAP NAS boxes, but with no add-ons and manual updates. Core is a bare Python install aimed at developers and nobody else. For the vast majority of buyers, HAOS on dedicated hardware is the right answer, because it is the only route that also gets you automatic backups, the add-on ecosystem and the migration wizard if you later move to a faster box.

What you get once it is running

Out of the box, the platform includes a drag-and-drop dashboard editor, a visual automation builder, scenes and scripts, a built-in energy dashboard that tracks consumption against tariff data, presence detection, backup and update management, and remote access handled inside the interface. Matter support is native through the Matter Server add-on. The HA Companion app for iOS and Android is free and handles presence detection and notifications — the arrival and departure signals most automations depend on.

Assist is the local voice assistant, and it is worth being clear about what it is: a local voice pipeline that requires configured speech-to-text and text-to-speech engines, such as the Whisper add-on, rather than a plug-and-play Alexa replacement. If you want hands-free voice without setup work, Alexa or Google Assistant via the Nabu Casa subscription is the easier path.

Home Assistant Voice Preview Edition

For a fully local wake-word satellite, Nabu Casa makes the Home Assistant Voice Preview Edition — dedicated hardware that listens for a wake word and feeds Assist without sending audio to a third party. It is the natural companion to a local voice pipeline and the hardware Nabu Casa documents at voice.home-assistant.io, where current pricing and availability are listed. Its honest caveat is the same one that applies to Assist generally: the intelligence comes from the STT and TTS engines you configure, not from the box, so a poorly configured pipeline will feel slower and clumsier than a commercial speaker. Best for privacy-focused tinkerers; skip it if you want voice to simply work.

The add-on and project ecosystem

Four names come up again and again in community discussions, and each solves a different problem:

• HACS (Home Assistant Community Store) installs third-party integrations and dashboard cards that are not part of the core project — the route to niche device support the core does not carry.
• ESPHome provides firmware for DIY ESP32 and ESP8266 sensors, backed by a first-party integration, so a cheap board can become a temperature, presence or plant sensor inside Home Assistant.
• Zigbee2MQTT is a popular alternative Zigbee stack that runs as an add-on under HAOS — relevant to the ZHA-versus-Zigbee2MQTT debate covered below.
• HomeKit Bridge is a built-in add-on that exposes Home Assistant entities to Apple Home, so iPhone households can keep Siri and the Home app while the logic lives locally.

For Matter, the Matter Server add-on handles Matter-over-Wi-Fi. Thread-over-Matter is the point where hardware matters: it additionally requires a Thread border router. Home Assistant Green has none, while Yellow has an onboard Silicon Labs MGM210P module that can serve that role.

UK energy: the sharpest reason to choose Home Assistant

This is the section no US-centric guide covers, and for British buyers it is often the deciding factor. The Octopus Energy integration is native to the core project, pulling live Agile and Intelligent tariff rates and triggering automations during the cheap windows. The practical use cases are concrete: scheduling EV charging into the cheapest half-hours, driving an immersion heater when rates drop, and arbitraging a home battery — charging when electricity is cheap, discharging or exporting when it is not.

SMETS2 smart meter data: n3rgy, the Octopus API and the Glow stick

To automate against real usage rather than tariffs alone, you need your smart meter’s data. UK SMETS2 meters can be read through n3rgy or the Octopus API. The community-maintained integration documentation at home-assistant.io/integrations/octopus_energy is the reference point, and r/homeassistant carries regular UK threads from users wiring up Agile and Intelligent tariffs.

If you want real-time rather than delayed data, the Hildebrand Glow stick is the named UK-specific piece of hardware: it exposes SMETS2 data over MQTT, which Home Assistant consumes natively. It costs approximately £30–£35 and is available from Hildebrand directly. Home Assistant software is where that data becomes useful — the stick alone only gives you a reading.

Hardware picks — and the commercial alternatives

Home Assistant Green

Best for: the majority of UK homes that want the full HAOS experience without tinkering.

Green ships with Home Assistant OS pre-installed, which means the add-on store, automatic monthly updates and the migration wizard are all present from day one. It is fanless and plug-and-play, connecting over Ethernet. The standout strength is how quickly owners get to a working system: r/homeassistant frequently reports initial setup under 30 minutes for HAOS on Green.

The honest caveat is radios. Green has no onboard Zigbee or Thread hardware, so anything wireless beyond Wi-Fi needs a USB dongle — the Connect ZBT-2 covered below. Verdict: the cheapest sane entry point to Home Assistant, provided you budget for a dongle if you own Zigbee devices.

Where to buy: The Pi Hut, or direct from the Home Assistant Store, at approximately £99–£110. Confirm current availability and pricing before ordering.

Home Assistant Yellow

Best for: households that want Zigbee and Thread without dongles hanging off the chassis.

Yellow includes built-in radios — an onboard Silicon Labs MGM210P module — and offers optional PoE, which makes for a single tidy box rather than a hub plus dongles. Its onboard radio is what makes Thread-over-Matter work without a separate Thread border router, something Green cannot do on its own. The standout strength is that combination: power, radios and Thread border router duties in one enclosure.

The caveat is availability. Nabu Casa has reduced the prominence of Yellow, so verify it is still stocked at store.home-assistant.io before you plan around it. If it has been discontinued by the time you read this, the equivalent route is a Green plus a Connect ZBT-2 dongle. Verdict: the neatest single-box option if you can still buy one.

Where to buy: store.home-assistant.io, subject to availability.

Connect ZBT-2

Best for: Green owners, and anyone running HAOS on a Raspberry Pi or x86 box, who needs Zigbee or Thread connectivity.

The Connect ZBT-2 is Nabu Casa’s own USB Zigbee/Thread dongle and is the current generation, succeeding the ZBT-1. It costs approximately £20–£25 and plugs into a spare USB port, adding the radios your hub does not have. The standout strength is straightforward: it is first-party hardware from the same company that maintains the software, so there is no compatibility guesswork.

The caveat is that a dongle is still a dongle — it occupies a port and needs a moment of planning for USB extension placement in radio-noisy homes. Verdict: a small, near-essential add-on for Green owners with Zigbee kit.

Where to buy: the Home Assistant Store, at approximately £20–£25.

Homey Pro

Best for: anyone allergic to tinkering who still wants local control.

Homey Pro is the polished commercial answer: local processing, a refined app, and no YAML anywhere in sight. It costs approximately £350, roughly three times the Green’s price, and is available direct from Homey.app and from Amazon UK. The standout strength is that it delivers the headline benefit of local automation without the setup project.

The honest caveat is flexibility: a closed platform cannot match Home Assistant’s thousands of integrations, its quality-scale transparency or the HACS ecosystem of community add-ons. Verdict: buy it if your time is worth more than the difference in price; skip it if you want to automate something obscure.

Where to buy: Homey.app direct, or Amazon UK, at approximately £350.

Homey Mini

Best for: buyers who want the Homey experience at Home Assistant Green money.

Homey Mini now exists as a lower tier in the range at approximately £100 — broadly the same price band as a Home Assistant Green, but with the commercial ecosystem’s ease of use instead of HAOS’s flexibility. Check Homey.app for the full capability list, since the Mini’s specification differs from the Pro’s. The standout strength is price: it removes the cost objection to going commercial.

The caveat is that the same closed-platform trade-off applies, and a cheaper hub will have less headroom for large device counts. Verdict: the most direct like-for-like alternative to a Green for non-tinkerers.

Where to buy: Homey.app direct and Amazon UK, at approximately £100.

Hubitat Elevation C-8 Pro

Best for: tinkerers who want a commercial hub with deep rule-engine automation.

Hubitat sits between the two camps: more automation power than Homey, less polish than Apple or Google. The C-8 Pro is the current model to look for, though you should verify the current model designation before buying. The standout strength is its rule engine, which appeals to users who find Home Assistant’s YAML off-putting but still want conditional, multi-device logic.

The caveat is the most UK-specific of any pick here: Hubitat is import-only for Britain. There is no official UK retailer, so you should expect to add roughly 20% VAT on import and to handle any warranty or returns across borders. Verdict: capable, but the import overhead and lack of UK support make it a considered purchase rather than an impulse one.

Where to buy: import only — no official UK retailer.

How to choose

Work through four questions. First, how much do you want to tinker? If the answer is “not at all”, Homey Pro or Homey Mini is the honest recommendation, and Home Assistant software is the wrong tool. Second, do you need radios? A Green plus a Connect ZBT-2 covers Zigbee and Thread for around £120–£135 combined, while Yellow folds that into one box if you can find it. Third, do you already own a NAS? If so, the Container method lets you reuse hardware, accepting manual updates and no add-ons. Fourth, what is your energy setup? If you are on Octopus Agile or Intelligent, the native integration and an optional Hildebrand Glow stick are the strongest argument for choosing Home Assistant over any rival, because commercial hubs do not replicate that workflow as naturally.

What owners report: setup time, YAML and Zigbee stacks

Community feedback is consistent across r/homeassistant and the Home Assistant Community forum. Initial setup on Green is frequently reported at under 30 minutes. YAML is still required for advanced templating — the visual automation builder, introduced in 2023 and refined through the 2025 releases, handles roughly 80% of common automations without it, by the community’s own estimate, so the last fifth is where the learning curve lives. On Zigbee, community opinion splits roughly evenly between Zigbee2MQTT and the built-in ZHA, with Zigbee2MQTT generally preferred at larger device counts — a recurring theme in the long-running comparison threads on both platforms.

FAQ

Is Home Assistant software really free? Yes. The software costs £0, is released under the Apache 2.0 licence, and is maintained by Nabu Casa with a large volunteer community. There is no per-device fee and no feature paywall on the core platform. The money you spend goes on hardware to run it, plus the optional cloud subscription.

What does the Nabu Casa Cloud subscription actually buy me? Approximately £5 a month buys Alexa and Google Assistant voice integration and secure remote access without port-forwarding your router. It is optional — self-hosting both features is possible — but it removes the certificate and network configuration work. Check nabu-casa.com for the current GBP figure including VAT.

Can I run Home Assistant on a NAS or an old computer I already own? Yes, though with trade-offs. The Container method runs on Synology, QNAP and similar NAS hardware, but you lose the add-on store and must apply updates manually. If you want one-click add-ons and automatic monthly updates, HAOS on a Green, a Raspberry Pi or an x86 box is the better route.

Does Home Assistant work with Octopus Agile and my SMETS2 meter? Yes. The Octopus Energy integration is native to the core project and pulls live Agile and Intelligent rates for automations. For meter data, SMETS2 meters can be read via n3rgy or the Octopus API, and the Hildebrand Glow stick at approximately £30–£35 delivers real-time readings over MQTT. The integration documentation at home-assistant.io/integrations/octopus_energy is community-maintained.

Will my automations still run if the internet goes down? That is the core advantage of local processing: automations execute on your own hardware, so a broadband outage does not stop them. Voice control via Alexa or Google Assistant and remote access do depend on connectivity, and cloud-only devices will only remain controllable as far as their own APIs allow.

How do I add Zigbee or Thread devices to a Home Assistant Green? You add radios, because Green has none onboard. The Connect ZBT-2 USB dongle, at approximately £20–£25 from the Home Assistant Store, provides Zigbee and Thread connectivity. Note that Thread-over-Matter also requires a Thread border router, which Green does not include.

How much YAML do I actually need to learn? Less than the reputation suggests. The visual automation builder, introduced in 2023 and refined through the 2025 releases, covers roughly 80% of common automations without any YAML, by community estimate. Advanced templating and custom dashboards still expose the raw configuration, which is where the platform rewards patience.

Is Home Assistant suitable for a complete beginner? It is, if you choose HAOS on dedicated hardware and accept that you are running a small project rather than an appliance. Under-30-minute setups are commonly reported on r/homeassistant. Buyers who want zero configuration overhead are better served by Homey Pro at approximately £350 or Homey Mini at approximately £100.

What is the quality scale, and why does it matter when buying devices? Integrations are graded Gold, Silver, Bronze, Internal or Virtual rather than being split into “official” and “unofficial”. The grade reflects documentation, testing and maintainer commitment, so it tells you how much friction to expect. Checking the grade in the integrations index before buying hardware is the single most useful pre-purchase step.