NAS vs Mini PC Running Cost Comparator

What this tool answers

The form-factor decision for a home server is usually argued on purchase price and settled on running cost. Those two numbers move in opposite directions: a pre-built NAS costs more up front and includes bays, RAID management and a supported software stack, while a mini PC costs less, draws less power, and leaves you assembling the storage and backup story yourself.

This comparator takes an idle wattage and a load wattage for two devices, weights them by how many hours a day you actually run workloads, and reports the annual kilowatt-hours, the annual electricity cost and the multi-year total once hardware is included. It also tells you the break-even year, which is the number that usually ends the argument.

The measured basis

Only the first row is our own measurement. The EQi12 figures come from wall-meter readings published in our eqi12-measurement-data repository and in the measured power consumption lab. Everything else is a typical range assembled from published specifications, which is why the tool lets you overwrite both numbers with a reading from your own meter.

How the numbers are computed

avg watts  = (idle x (24 - load hours) + load x load hours) / 24
annual kWh = avg watts x 8760 / 1000
annual cost = annual kWh x rate
total cost  = purchase price + (annual cost x years)

break-even  = (priceB - priceA) / (annualCostA - annualCostB)
              only when the pricier device is the cheaper one to run

Weighting matters more than it looks. A server that idles 22 hours a day is an idle-power decision, not a load-power decision: at 4 load hours per day, each watt of idle costs roughly five times what a watt of load does. If your machine genuinely runs transcodes or backups around the clock, raise the load hours and the ranking can change.

Worked example

A Beelink EQi12 at 12W idle and 37W load, against a 4-bay x86 NAS at 40W idle and 80W load, with 4 load hours a day at $0.16/kWh. The mini PC averages about 16.2W and consumes roughly 142 kWh a year, costing about $23. The NAS averages about 46.7W, consumes roughly 409 kWh a year, and costs about $65. Over three years that is a difference of about $128 in electricity alone, and it runs the wrong way for the NAS: it costs more to buy and more to run. On pure cost there is no break-even point to compute. That is not an argument against a NAS — you buy it for bays, hot-swap, RAID management and a supported software stack — but it does mean you should not buy one expecting it to pay for itself on power.

A break-even story does exist when the cheap option is the thirsty one. Take a used desktop at 80W idle and 200W load costing $120, against a mini PC at 12W and 37W costing $380, again at $0.16/kWh and 4 load hours. The desktop draws 100W average and 876 kWh a year for about $140; the mini PC draws about 16W average and 142 kWh for about $23. The mini PC's $260 premium is repaid by the $117 annual saving in roughly 2.2 years. Raise the rate to $0.35/kWh and the same hardware repays in about 1.0 year. That sensitivity is the point: the answer depends on your electricity price and your workload profile, not on which box is objectively better.

Assumptions and limitations

• Only the EQi12 numbers are measured on our hardware. Every other preset is a typical range from published specifications — treat it as a starting point and replace it with a meter reading.
• The model uses two power states. Real servers spend time in between, and tasks like disk spin-up, scrubs, backups and nightly transcodes create peaks that a two-state average smooths away.
• Purchase price defaults to 0 on purpose. We do not track retail pricing, and a comparison that mixes guessed hardware prices with measured power draw is worse than one that reports power honestly.
• Drives, UPS capacity, replacement fans and cooling are not included. A fully populated 4-bay NAS draws noticeably more than an empty one, and each spinning disk adds a few watts at idle.
• This compares running cost only. Bays, hot-swap, RAID management, vendor support, noise, and whether you want to administer the box at all are real costs that do not appear on an electricity bill.

Frequently asked questions