Used business mini PC or new low-power model?

Our recommendation by job

For a budget dedicated service, compare the HP ProDesk 400 G5 Mini, i5-8500T, 8GB RAM and 256GB SSD. Its seller listed £149.99 and stock on 21 October; VAT inclusion was unconfirmed, so check the final total and current availability. For a newer media platform, compare the AIR12 Lite N150. These are specification-based starting points, not tested performance results.

1. Turn the headline price into a usable price

Write down these five amounts for each candidate:

1. PC price including VAT. If the tax treatment is unclear, resolve it before comparing totals.
2. Missing RAM or SSD. “Barebones” means you need to check what is absent; never compare that price directly with a populated machine.
3. Power adapter, mains lead and delivery. Include them even if the seller lists them as options.
4. Immediate upgrades. Price the memory and storage you need on day one, not a hypothetical maximum you may never use.
5. Electricity over your ownership period. Use the calculator with measured power or several clearly labelled assumptions.

Keep warranty and repair risk alongside the total as a separate judgement. Do not invent a precise repair allowance without evidence.

2. Check whether the premium pays back

Here is an illustrative three-year comparison. The prices and wattages are invented examples, not measurements or offers for the linked machines. Both run continuously at 25p/kWh.

The used PC costs £67.15 less over three years. The new one saves only £32.85 in electricity during that time. Its £100 premium takes about 9.1 years to recover from power savings alone.

Choose the new PC if a feature or warranty is worth the remaining premium to you. In this example, lower electricity use alone does not repay it within three years.

3. Know when to pay more—and when to walk away

Pay for a newer media platform when you need conversion. Jellyfin's current guidance warns new buyers about declining support for older Intel integrated-graphics toolkits. Read the playback guide before treating an old i7 as an upgrade over a newer low-cost processor.

Pay for a clear upgrade path when you will use it. For a planned 32GB setup, ask whether a 16GB offer contains one 16GB module or two 8GB modules. On a two-slot machine, that changes whether you can add memory or need to replace it.

Reject an offer when a necessary detail remains unanswered. Examples: locked BIOS for a Home Assistant install, an unconfirmed final tax-inclusive price, or an unclear RAM limit when your workload needs more than the included memory. Choose another listing rather than buying around an assumption.

4. Check update support before paying

Choose the operating system first. A seller's Windows 11 badge does not establish that the hardware meets Microsoft's requirements, and it adds little value if you will replace Windows with Home Assistant OS.

1. For Windows, ask for the exact CPU and evidence that the PC meets Microsoft's requirements without a bypass. These include an approved processor, TPM 2.0 and UEFI firmware capable of Secure Boot, alongside the other Windows 11 requirements. Microsoft says ineligible hardware is unsupported and updates are not guaranteed. If the seller can only say it is installed, keep looking when supported Windows is essential.
2. For a dedicated Home Assistant PC, check its own installation requirements. The official x86-64 guide calls for a 64-bit machine with UEFI, Secure Boot disabled for this installation, and a boot drive using 512-byte logical sectors. Ask whether BIOS settings are accessible before buying. Installing HAOS directly replaces the existing operating system and data: back up anything needed first. Windows eligibility is a different question.
3. Check firmware separately from the operating system. Ask for the exact model, installed BIOS version and manufacturer's support-page link. Compare available releases and read their installation instructions. If you cannot find an official update route, treat that as a reason to choose another machine. A recent BIOS release is useful evidence, but does not promise future updates; equally, a CPU lifecycle date alone does not establish the whole PC's support status.

Copy this to the seller: “Please confirm the exact CPU, that BIOS settings are unlocked, the installed BIOS version and the official support-page link. If I will use Windows 11, what evidence confirms this unit meets Microsoft's hardware requirements without a bypass?”

For an always-on machine, our buying judgement is to favour a configuration with a clear update route over a small saving with unanswered support questions. This check does not certify any catalogue model as secure or guarantee a support lifetime.