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 up to 3 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 roughly 1.5–3× more power than a purpose-built NAS under moderate use, and an old workstation can draw considerably more. At Australian electricity rates — particularly in SA — 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.
| 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 and the NAS is cheaper to run, the NAS wins from day 1. If the NAS costs more upfront, break-even is how long until its lower running cost pays that back. If the NAS is cheaper upfront but costlier to run, break-even instead marks the point where the PC's lower running cost overtakes it — read the verdict text for which case applies.
Worked example: DS425+ (29W, $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 = 29×8760/1000 = 254.0 kWh → $88.9/yr. Annual saving: $87.4. Break-even: $790 ÷ $87.4 = 9.0 years.
| State | Rate (c/kWh) | NAS Annual | PC Annual | Annual Saving | Break-even |
|---|---|---|---|---|---|
| NSW | 35c | $89/yr | $176/yr | $87/yr | 9.0 yrs |
| VIC | 30c | $76/yr | $151/yr | $75/yr | 10.5 yrs |
| QLD | 30c | $76/yr | $151/yr | $75/yr | 10.5 yrs |
| SA | 42c | $107/yr | $212/yr | $105/yr | 7.5 yrs |
| WA | 31c | $79/yr | $156/yr | $77/yr | 10.2 yrs |
| TAS | 28c | $71/yr | $141/yr | $70/yr | 11.3 yrs |
| ACT | 36c | $91/yr | $181/yr | $90/yr | 8.8 yrs |
| NT | 29c | $74/yr | $146/yr | $72/yr | 10.9 yrs |
DS425+ vs old Intel 8th gen desktop, Moderate usage (25% load, 75% idle). Rates are indicative state averages, current as of March 2026. NSW, SA and ACT 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.
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