Is an old PC cheaper to run than a NAS?

Usually not, once electricity costs are factored in. A typical old Intel or AMD desktop draws 45-95W idle-to-load, while a purpose-built NAS draws 22-40W. At NSW rates (35c/kWh), that difference costs $50-120/year extra. In SA at 42c/kWh, an old Xeon workstation can cost $300+/year more in electricity than a Synology NAS, recovering the NAS's purchase price in 3-4 years.

NAS vs Repurposed PC Cost Comparison — Is an Old PC Really Cheaper?

This NAS versus repurposed PC cost comparison calculator works out whether building a NAS from an old PC is actually cheaper than buying a dedicated NAS unit. Factors in power consumption, hardware costs, and Australian electricity rates over 5 years.

Find out whether buying a purpose-built NAS or repurposing an old PC is the cheaper option over 3 years — factoring in upfront cost, electricity, and software.

The "use an old PC" argument looks compelling until you run the electricity numbers. A typical old Intel or AMD desktop draws 3–5× more power than a purpose-built NAS. At Australian electricity rates — particularly in SA and WA — that difference adds up faster than most people expect.

Defaults to Australian rates. If you're outside Australia, select your region or enter a custom rate.

Your Setup

Purpose-built NAS

NAS Model

Watts (typical)

Upfront Cost ($)

Price is for unit only, not drives.

Repurposed PC

PC Type

Idle Watts

Load Watts

Upfront Cost ($)

PC Software / OS

Synology/QNAP software is included in NAS price, no extra cost.

Usage Profile

Electricity Rate

Rates verified March 2026.

Comparison Period

Results

Calculating…

NAS Annual Electricity

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PC Annual Electricity

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Annual Saving (NAS)

—

Break-even

—

Total Cost of Ownership

	NAS	PC
Hardware (upfront)	—	—
Software	$0	—
Electricity	—	—
Total	—	—

NAS annual kWh = NAS watts × 8760 hours ÷ 1000. NAS presets use a single 'typical' watt figure (averaged idle/load).

PC annual kWh = (active% × load W + idle% × idle W) × 8760 ÷ 1000.

Annual cost = annual kWh × (rate c/kWh ÷ 100).

Total cost = upfront hardware + software + (annual electricity × years).

Break-even = (NAS upfront − PC upfront − PC software) ÷ annual electricity saving. If the PC costs more upfront, the NAS wins from day 1.

Worked example: DS425+ (32W, $790) vs old Intel desktop (95W load, 45W idle, $0). Moderate (25%/75%). NSW 35c. PC annual = (0.25×95 + 0.75×45)×8760/1000 = 503.7 kWh → $176.3/yr. NAS = 32×8760/1000 = 280.3 kWh → $98.1/yr. Annual saving: $78.2. Break-even: $790 ÷ $78.2 = 10.1 years.

AU Reference: Break-even by State (DS425+ vs Old Intel Desktop, Moderate)

State	Rate (c/kWh)	NAS Annual	PC Annual	Annual Saving	Break-even
NSW	35c	$98/yr	$176/yr	$78/yr	10.1 yrs
VIC	30c	$84/yr	$151/yr	$67/yr	11.8 yrs
QLD	30c	$84/yr	$151/yr	$67/yr	11.8 yrs
SA	42c	$118/yr	$212/yr	$94/yr	8.4 yrs
WA	31c	$87/yr	$156/yr	$69/yr	11.4 yrs
TAS	28c	$78/yr	$141/yr	$63/yr	12.5 yrs
ACT	30c	$84/yr	$151/yr	$67/yr	11.8 yrs
NT	29c	$81/yr	$146/yr	$65/yr	12.2 yrs

DS425+ vs old Intel 8th gen desktop, Moderate usage (25% load, 75% idle). Rates verified March 2026. SA and WA users see break-even under 10 years — meaningful for hardware that lasts 5–8 years. Power pricing in SA (42c/kWh) is among the highest in the developed world. At SA rates, a 100W always-on server costs ~$368/year to run — more than many Synology NAS units cost outright.

NBN upload speeds affect your NAS remote access capability regardless of hardware — see our NBN Remote Access Reality Checker for AU-specific limits. Australian Consumer Law gives you minimum warranty rights on all hardware purchased in Australia.

Frequently Asked Questions

Usually not, once electricity costs are factored in. A typical old Intel or AMD desktop draws 45–95W idle-to-load, while a purpose-built NAS draws 22–40W. At NSW rates (35c/kWh), that difference costs $60–120/year extra. In SA at 42c/kWh, an old Xeon workstation can cost $300+/year more in electricity than a Synology NAS — recovering the NAS's purchase price in 3–4 years.

TrueNAS SCALE and OMV (OpenMediaVault) are the most popular free options. TrueNAS SCALE is Linux-based with Docker/KVM support and excellent ZFS integration. OMV is Debian-based, simpler to set up, and has a large plugin library. Unraid has a one-time licence fee (~$70 USD) but is highly flexible for mixed drive sizes and Docker containers.

An Intel N100 or N200 mini PC is genuinely close to a purpose-built NAS in efficiency (8–20W at load) and often costs $150–250 AUD. With TrueNAS SCALE or OMV, it makes a compelling DIY NAS — especially if you need more RAM or compute than a typical Synology allows. The trade-off: less NAS-specific features, no enterprise RAID controller, and no drive hot-swap.

It depends heavily on the PC. An old Intel desktop (6th–8th gen) draws roughly 45–95W and costs $130–200/year in NSW. A modern mini PC (Intel N100) draws 8–20W and costs $25–60/year — similar to a purpose-built NAS. SA users pay ~50% more for the same hardware due to the state's high electricity rates.

A NAS (Network-Attached Storage) is a purpose-built device for storing and sharing files over a network. Unlike a general PC, it's optimised for low power use, 24/7 operation, and features specific to file storage — RAID management, remote access, backup scheduling, and media serving. See our guide: What is a NAS? for a full comparison.

Assumptions and risk factors NAS wattage presets use a single "typical" figure rather than modelling idle/load separately, and PC wattage varies significantly with age, components and BIOS power settings, measure your actual hardware with a power meter for a precise figure. Upfront prices are indicative AU street prices and move over time. This calculator does not account for the value of your own time spent building and maintaining a DIY NAS, or reliability differences between purpose-built and repurposed hardware.

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