The Best Home Assistant Servers in 2026: Green, Yellow, Raspberry Pi 5 and Mini PCs Compared

Picking the right Home Assistant server is the single decision that determines whether your smart home feels instant or infuriating. Choose too little and your Zigbee network stutters, your database corrupts on a cheap SD card, and every dashboard refresh feels like dial-up. Choose too much and you have spent several hundred pounds on a machine that idles at three per cent CPU. This guide compares the realistic UK options in 2026 — Nabu Casa’s own plug-and-play boxes, a Raspberry Pi 5 self-build, and second-hand enterprise mini PCs — on price, specs, running cost and setup effort.

Everything here is desk research. The figures come from manufacturer specification sheets, published expert coverage and aggregated owner feedback across Reddit’s r/homeassistant, the Home Assistant Community Forum and UK retailer review sections. No hands-on testing was performed for this article, and prices move constantly, so treat every figure below as an approximation. Prices were checked in June 2026.

Quick Picks

What a Home Assistant Server Actually Does

Home Assistant is free, open-source home automation software. It runs on a “server” — any always-on machine that stays powered 24/7 — and it pulls together devices that would otherwise live in separate apps: Philips Hue, IKEA TRÅDFRI, Shelly relays, Sonos, Hive, Ring, Zigbee and Matter sensors, plus hundreds of cloud integrations.

Because it is local-first, your automations keep running when your broadband drops. That is the core selling point. But the experience rides entirely on the host hardware:

• RAM determines how many add-ons you can run simultaneously — Mosquitto, Zigbee2MQTT, Node-RED, ESPHome and Frigate all compete for the same memory.
• Storage type decides reliability. SD cards wear out; NVMe SSDs generally do not.
• CPU affects dashboard responsiveness and whether you can run local object detection on camera feeds at all.
• Radios — Zigbee and Thread — are either built into the board or bolted on afterwards via a USB dongle.

According to the official Home Assistant documentation, the platform supports four installation methods: Home Assistant OS (the recommended appliance route), Supervised, Container and Core. Supervised is officially described as being “for advanced users” and carries strict host requirements — it is not deprecated, but it sits in unsupported-adjacent territory that most buyers should avoid. For the overwhelming majority of households, Home Assistant OS on dedicated hardware is the correct answer.

How to Choose a Home Assistant Server

Four questions settle almost every buying decision.

How many devices and add-ons will you run? Owner consensus on r/homeassistant and the HA Community Forum points to a set of “move on” triggers: more than 100 devices, more than two cameras, a database larger than 10 GB, or more than eight add-ons running simultaneously. Below those numbers, an entry-level appliance is genuinely sufficient. Above them, you want more RAM and faster storage.

Do you need NVMe? The difference matters more than it sounds. eMMC and SD storage is soldered or slotted flash with limited write endurance, and Home Assistant writes to its database constantly. NVMe over PCIe is faster and far more durable under that workload. SD card corruption is the single most-cited hardware failure mode in the HA Community Forum’s hardware category — which is why every recommendation below either ships with eMMC, an NVMe slot, or both.

Do you need a built-in radio? Zigbee and Thread are the two mesh protocols your sensors and bulbs most often speak. Some servers include the radio; others require a USB dongle. If you go the dongle route, be aware of a documented and recurring complaint: USB 3.0 ports emit interference in the 2.4 GHz band that Zigbee uses. Community fixes are to plug the dongle into a USB 2.0 port or use a short USB extension cable with a ferrite choke.

What will it cost to run? A server is on 24/7, so idle draw is a real line item. At a UK rate of 24.5p per kWh, the difference between the most efficient and least efficient options here is substantial — that comparison is set out at the end of this guide.

The Best Home Assistant Servers in 2026

1. Home Assistant Green — Best Overall for Most People

Best for: households that want Home Assistant working this afternoon with no Linux knowledge.

Home Assistant Green is Nabu Casa’s entry-level appliance: a fanless, palm-sized box pre-loaded with Home Assistant OS. The specification is a Rockchip RK3566 system-on-chip — a quad-core Cortex-A55 running at 1.8 GHz — paired with 4 GB of LPDDR4 RAM and 32 GB of eMMC storage. You plug in power and Ethernet, open the app, and you are running within minutes.

What is deliberately absent is as important as what is present. The Green has no Zigbee or Thread radio and no NVMe slot, both by design — Nabu Casa built a sealed, supportable appliance rather than an expandable one. That means the correct unit of purchase is not the Green alone: you should budget for a Home Assistant Connect ZBT-1 dongle, approximately £25–£35 from The Pi Hut, which adds Zigbee and Thread over USB. The Green-plus-ZBT-1 bundle is the configuration to plan around.

Standout strength: running cost and simplicity together. Community-reported idle draw on r/homeassistant is around 5 W, which works out at roughly £10.70 a year at 24.5p per kWh. It is UKCA-marked and carries a Nabu Casa one-year warranty with EU/UK RMA handled through nabu.casa.

Honest caveat: the RK3566 cannot usefully run Frigate with hardware-accelerated object detection — community consensus is clear that Frigate needs an N100-class CPU at minimum. If camera AI is on your roadmap, the Green is the wrong starting point.

Verdict: the default answer for most UK homes, provided you buy the ZBT-1 alongside it.

Where to buy: Amazon UK, The Pi Hut and Pimoroni all typically stock the Green; the Connect ZBT-1 is commonly available from The Pi Hut.

2. Home Assistant Yellow — Best for Zigbee and NVMe in One Official Box

Best for: buyers who want Nabu Casa support, a built-in radio and local SSD storage without assembling anything.

The Yellow is built around a Raspberry Pi CM4 compute module and adds two things the Green omits. First, an integrated Silicon Labs MGM210P radio, giving Zigbee and Thread out of the box with no dongle and no USB 3.0 interference to worry about. Second, an M.2 NVMe slot running over PCIe Gen 2, so you can move your database and recordings onto an SSD.

It ships as kits: either a CM4 with 2 GB RAM and 8 GB eMMC, or a CM4 with 4 GB RAM and 32 GB eMMC. Verify the exact SKU against the current nabu.casa shop listing before buying, because CM4 procurement constraints have caused kit changes in the past. A bare board without the CM4 is cheaper but requires you to source the compute module separately.

Standout strength: it is the only official Nabu Casa box that solves radios and storage in one enclosure, which removes two of the three common upgrade triggers at once.

Honest caveat: availability. The Yellow has historically been supply-constrained, so confirm live stock at nabu.casa/yellow before recommending or ordering it — do not assume it is in stock.

Verdict: the neatest one-box solution if it is available and your budget stretches to it.

Where to buy: the Nabu Casa shop at nabu.casa is the primary channel; UK distributors such as The Pi Hut ship duty-paid, which matters for the import-VAT point explained below. Expect to pay approximately £180–£230 for a CM4-included kit.

3. Beelink Mini S12 Pro (or Equivalent Intel N100 Mini PC) — Best for Power Users

Best for: households running Frigate, many add-ons, or both.

The Intel N100 is an Alder Lake-N part: four cores, a 6 W TDP, and Intel UHD graphics that can handle hardware video decode — the feature that makes Frigate’s local object detection viable without a discrete GPU. Typical Beelink Mini S12 Pro configurations pair it with 16 GB of DDR4 and a 500 GB NVMe drive, though you should confirm the current Beelink listing before ordering. The same N100 class also includes the Trigkey S5 and the GMKtec NucBox G3.

Standout strength: value per watt, particularly in the refurbished corporate market. Used Lenovo ThinkCentre M720q and Dell OptiPlex Micro 7060 machines typically sell for approximately £80–£130 refurbished — less than a new mini PC, with enterprise-grade build quality. These are commonly listed on eBay UK, Tier1 Online and Bargain Hardware.

Honest caveat: refurbished units carry no UKCA obligation because they are used goods, so the protection you get is the seller’s warranty rather than a conformity mark. Check for a 12-month seller warranty — Tier1 Online and Bargain Hardware offer this as standard. On the new side, idle draw is the trade-off: Intel’s ARK database lists the N100 TDP at 6 W, but community-reported real-world idle is closer to 10 W, within a rough 8–12 W band, which is roughly £21 a year at 24.5p per kWh — about double the Green.

Verdict: the right choice the moment cameras, heavy add-on counts or a growing database enter the picture.

Where to buy: new N100 mini PCs are typically stocked by major online retailers; refurbished business micro PCs are commonly found on eBay UK, Tier1 Online and Bargain Hardware.

4. Raspberry Pi 5 (8 GB) + M.2 HAT+ — Best Self-Build

Best for: tinkerers who want the lowest idle draw and every component individually replaceable.

A Pi 5 build is the only option here where you can swap any single part. The line-by-line cost breaks down like this:

• Raspberry Pi 5 board, 8 GB: approximately £75–£80, from Pimoroni, The Pi Hut or RS Components — verify June 2026 pricing before ordering.
• Official M.2 HAT+: approximately £12, the accessory that exposes the Pi 5’s PCIe lane to an NVMe drive.
• 256 GB NVMe SSD (for example a WD SN580): approximately £25–£35.
• Official 27 W USB-C power supply: approximately £12.
• Case and cooler: approximately £8–£15.

That comes to approximately £135–£160 all-in, which undercuts a new N100 mini PC while offering faster storage than the Green. Idle draw is the headline: community-reported figures put it at roughly 3–5 W, equating to approximately £6.50–£11 a year at 24.5p per kWh — the lowest of any capable option in this guide.

Standout strength: repairability plus efficiency. If a component fails, you replace that component rather than the whole unit, and nothing else here idles as low.

Honest caveat: it is a build, not an appliance. You assemble it, flash the OS yourself, and you inherit the USB 3.0/Zigbee interference problem if you add a radio dongle to a USB 3.0 port — use a USB 2.0 port or a ferrite-choked extension cable instead.

Verdict: the best value for anyone comfortable with a screwdriver.

Where to buy: Pimoroni, The Pi Hut and RS Components typically stock the board and official accessories.

Running Costs Compared: The ROI Argument

Because these machines run 24/7, idle draw is a genuine part of total cost of ownership. At a UK electricity rate of 24.5p per kWh, the numbers stack up as follows:

• Raspberry Pi 5 (8 GB): around 3–5 W, approximately £6.50–£11 a year.
• Home Assistant Green: around 5 W, approximately £10.70 a year.
• Home Assistant Yellow: around 7–9 W (community-reported), approximately £15–£20 a year.
• Intel N100 mini PC: around 8–12 W (community-reported), approximately £21 a year.

The comparison that makes the argument is against an over-specced desktop repurposed as a server, which can draw upwards of £80 a year at the same tariff. Against the Green’s roughly £11 a year, that is the difference that justifies buying a purpose-built low-power box rather than reusing an old tower PC.

UK Buying Notes: Stock, Warranty, Duties and Subscriptions

A few practical points that catch UK buyers out.

Ordering direct from the US. The Nabu Casa store ships from the United States, which means import VAT applies on arrival. UK distributors such as The Pi Hut ship duty-paid, so the price you see is the price you pay — often worth the small premium for the avoided paperwork.

Nabu Casa Cloud. Remote access and voice assistant integration are subscription features rather than hardware ones, priced at approximately £6.50 a month. Budget for it as a separate line item if you want to reach your dashboard from outside the home without configuring your own VPN or reverse proxy.

Warranty and returns. The Green carries a Nabu Casa one-year warranty with EU/UK RMA handled via nabu.casa. Refurbished mini PCs are covered by the seller’s warranty instead — look for 12 months, which Tier1 Online and Bargain Hardware offer as standard.

Radio interference. If you add a USB Zigbee dongle to any of these machines, remember the USB 3.0 interference point covered earlier: use a USB 2.0 port or a ferrite-choked extension cable.

Frequently Asked Questions

Do I need a dedicated computer, or can I run Home Assistant on something I already own? You can run it on existing hardware, but the reliability trade-off is usually not worth it. According to the official Home Assistant documentation, the supported methods are Home Assistant OS, Supervised, Container and Core. Supervised is officially described as being for advanced users with strict host requirements, and Container and Core both leave you managing the operating system yourself. A dedicated, low-power box running Home Assistant OS is the route that avoids that maintenance burden.

Do I need to buy the Connect ZBT-1 with the Home Assistant Green? Yes, if you want Zigbee or Thread devices. The Green has no radio built in, which is a deliberate design choice rather than an omission, so pairing it with a Home Assistant Connect ZBT-1 is the correct configuration. That dongle typically costs around £25–£35 from The Pi Hut. Budget for it as part of the purchase, not as an optional extra.

What is the difference between Home Assistant OS, Supervised, Container and Core? Home Assistant OS is a complete appliance image that manages the operating system and add-ons for you — the recommended route. Supervised adds the supervisor layer on top of an operating system you manage, with strict host requirements and an “advanced users” label. Container and Core are progressively more manual: you supply the OS, the container runtime and the updates. For most buyers, OS on dedicated hardware is the only sensible choice.

Will a Raspberry Pi 5 be powerful enough for Frigate and camera detection? That depends on how many cameras and whether you need hardware-accelerated decode. Community consensus is that Frigate with hardware decode requires an N100-class CPU at minimum — which the Pi 5 does not provide in the same way the Intel UHD graphics on an N100 do. What the Pi 5 does offer is more than enough for a large Zigbee network, dozens of add-ons and a sizeable database, at the lowest idle draw in this guide.

When should I upgrade from a Green to something more powerful? Owner consensus on r/homeassistant and the HA Community Forum points to four triggers: more than 100 devices, more than two cameras, a database larger than 10 GB, or more than eight add-ons running at once. Hit any one of those and an entry-level appliance starts to feel constrained. The natural upgrade paths are an Intel N100 mini PC for camera work, or a Yellow or Raspberry Pi 5 build with NVMe storage if your database is the bottleneck.

How much does a Home Assistant server cost to run in the UK? At 24.5p per kWh, the Raspberry Pi 5 lands at approximately £6.50–£11 a year, the Green at around £10.70, the Yellow at around £15–£20 and an N100 mini PC at around £21. All of those are far below an over-specced desktop PC, which can exceed £80 a year at the same rate. Because these machines never switch off, that gap compounds over the life of the hardware.

Is buying a refurbished mini PC safe for Home Assistant? It is one of the better-value routes, provided you buy from a seller offering a proper warranty. Tier1 Online and Bargain Hardware both offer 12-month warranties as standard, and used corporate machines such as the Lenovo ThinkCentre M720q and Dell OptiPlex Micro 7060 are typically listed at around £80–£130. Note that used goods carry no UKCA obligation, so the warranty is your protection rather than conformity marking.

Can I avoid import charges when ordering from Nabu Casa? Yes, by buying through a UK distributor instead. Ordering direct from the US nabu.casa store means import VAT applies on arrival. UK distributors such as The Pi Hut ship duty-paid, so the advertised price includes everything. That is usually the simpler option for a Green or Yellow purchase.

Bottom Line

For most UK households, the Home Assistant Green plus a Connect ZBT-1 is the right purchase — around £95–£115 for the hub and roughly £25–£35 for the radio, running for about £10.70 a year. If you want Zigbee and NVMe handled officially in one box, check whether the Yellow is in stock at around £180–£230. If cameras or heavy add-on counts are on your roadmap, an Intel N100 mini PC — ideally a refurbished corporate unit at around £80–£130 — gives you the headroom. And if you want the lowest running cost and a machine where every part is replaceable, the Raspberry Pi 5 build at around £135–£160 all-in is the one to assemble.