Home Assistant Green: What It Is, What It Costs and What to Add

What Home Assistant Green is

Home Assistant Green is a small hub that comes with Home Assistant already installed. Home Assistant is free, open-source software that connects smart devices from hundreds of brands and runs your automations on your own hardware instead of a company's cloud. Its makers describe the Green as "the easiest way to start using Home Assistant": plug in power and Ethernet, open the app, and it starts finding devices.

It's designed and sold by Nabu Casa, the company behind Home Assistant, which says most of its profit goes to the Open Home Foundation that funds the project. This guide is based on the published specs and documentation, checked in October 2026. Kotoh Home has no commercial relationship with Nabu Casa.

Specs and price

The Green's case is translucent polycarbonate with a large aluminum heat sink, so it runs silently with no fan.

What it can do on its own

Out of the box, the Green talks to any device that connects over your home network. That includes many Wi-Fi and Ethernet devices with local integrations, such as UniFi and Reolink cameras, Lutron Caséta lighting (through Lutron's hub), Philips Hue (through the Hue Bridge), and Shelly relays. It can also pair Apple HomeKit-compatible devices directly with its HomeKit Device integration, which keeps them local.

Matter devices that use Wi-Fi or Ethernet work with the Green too, since Home Assistant is a Matter controller. Matter devices that use Thread need a Thread radio, which brings us to the add-ons.

What to add: radios

Many of the best local devices, including most battery sensors, many locks and leak sensors, use low-power mesh radios rather than Wi-Fi. The Green has two USB ports for official adapters:

• Home Assistant Connect ZBT-2 ($49): for Zigbee or Thread. Home Assistant says it can't run both at the same time, so homes that want both use two adapters.
• Home Assistant Connect ZWA-2 ($69): for Z-Wave, with the latest 800-series chip and support for Z-Wave Long Range, running both networks at once.

Placing the adapters

Radio placement matters more than people expect. Home Assistant's Zigbee documentation recommends a USB extension cable, a USB 2.0 port, and keeping the adapter away from USB 3.0 devices, which can interfere with 2.4 GHz radios. In practice, that means not plugging the adapter straight into the back of the hub next to your router. Put it on a short cable, in an open spot near the middle of the house if you can.

Not sure which radio you need? Our guide to Zigbee vs Z-Wave vs Thread explains the differences and what each is good for.

Green vs Yellow vs your own hardware

Home Assistant runs on several kinds of hardware, and the Green is the simplest. Here's how the options compare.

When a mini PC makes more sense

The Green is built to run Home Assistant itself. If you want AI object detection on cameras (Frigate), many cameras recording to the same box, or a local AI model for voice, put those on separate, more powerful hardware or use a mini PC for the whole system. For larger houses, that's usually the better design, and it can still be kept as simple to maintain as a Green.

Does it work without the internet?

Yes, for everything local. Home Assistant says the Green needs internet only for initial setup. After that, devices with local integrations, Zigbee, Z-Wave, Thread and Matter devices, and all your automations run on the hub. The things that need the internet are the things that are cloud-based by design: remote access from outside the house, cloud voice, and devices whose integrations are labeled "Cloud Polling" or "Cloud Push".

Remote access and Home Assistant Link

To reach your home from anywhere, Nabu Casa offers Home Assistant Link (formerly Home Assistant Cloud) for $6.50 a month or $65 a year. It also handles backups and connects Home Assistant to Alexa and Google Home if you still use them. It's optional. An installer can set up other secure remote access instead.

Who the Green is for

• A good fit: homes with mixed brands that want one app, local control, and no lock-in to a single ecosystem.
• A good fit: second homes, where automations and alerts need to keep running when the internet drops.
• Think twice: if nobody in the house wants to own the system. Home Assistant is powerful but needs updates and occasional attention. That's the gap a care plan fills.

If you're comparing the Green with Hubitat, SmartThings or Aqara, see our guide to the best smart home hub. If you're weighing it against dealer systems, see Home Assistant vs Control4 vs Crestron.

Setting up a Green, step by step

1. Plug it in. Connect power and an Ethernet cable to your router. The Green has no Wi-Fi setup step, which keeps it reliable.
2. Open the app. Install the Home Assistant app, or use a web browser on the same network. The setup wizard finds the Green and walks you through creating an account that lives on the hub, not online.
3. Let it discover devices. Home Assistant automatically detects many devices already on your network and offers to add them.
4. Add radios. Plug in a Connect ZBT-2 or ZWA-2 and follow the prompt to start a Zigbee, Thread or Z-Wave network, or migrate an existing one.
5. Organize by area. Assign devices to rooms and floors. This pays off later for voice control and for automations like "turn off everything downstairs".
6. Set up backups. Turn on automatic backups and store a copy somewhere other than the Green itself.

Updates and upkeep

Home Assistant ships updates often, and the Green installs them from the app with a click. Most updates are uneventful, but because Home Assistant connects to hundreds of brands, an update occasionally changes how a device or integration behaves. Good habits help: take a backup before major updates, read the release notes for integrations you rely on, and don't update the night before you leave a second home empty for a month.

That upkeep is the main cost of owning Home Assistant rather than renting a closed system. For a primary home with an interested owner, it's light work. For an empty second home, or a family that doesn't want to think about it, it's worth having someone responsible for it.

Adding voice and AI

The Green pairs with Home Assistant's own voice hardware, the Voice Preview Edition, which listens for its wake word on the device. For natural, conversational requests, Home Assistant can connect to an AI model. That model can run on a separate computer in the house or on a private server, rather than at a big AI company.

Where Kotoh Home fits

Every Kotoh Home tier includes a Home Assistant hub running in the house, so lights, locks, routines and alerts work locally even with the internet down. We choose the hardware for the size of the home, from a Green to a more powerful machine, set up the radios and devices, and keep it updated on a care plan. See our smart home installation service for how it works.