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, $899) vs old Intel desktop (95W load, 45W idle, $0). Moderate (25%/75%). NSW 34.0c. PC annual = (0.25×95 + 0.75×45)×8760/1000 = 503.7 kWh → $171.1/yr. NAS = 29×8760/1000 = 254.0 kWh → $86.3/yr. Annual saving: $84.8. Break-even: $899 ÷ $84.8 = 10.6 years.
| State | Rate (c/kWh) | NAS Annual | PC Annual | Annual Saving | Break-even |
|---|---|---|---|---|---|
| NSW | 34.0c | $86/yr | $171/yr | $85/yr | 10.6 yrs |
| VIC | 28.2c | $72/yr | $142/yr | $70/yr | 12.8 yrs |
| QLD | 28.0c | $71/yr | $141/yr | $70/yr | 12.9 yrs |
| SA | 41.9c | $106/yr | $211/yr | $105/yr | 8.6 yrs |
| WA | 33.3c | $84/yr | $168/yr | $83/yr | 10.8 yrs |
| TAS | 24.8c | $63/yr | $125/yr | $62/yr | 14.5 yrs |
| ACT | 37.0c | $94/yr | $186/yr | $92/yr | 9.7 yrs |
| NT | 31.7c | $80/yr | $160/yr | $79/yr | 11.4 yrs |
DS425+ vs old Intel 8th gen desktop, Moderate usage (25% load, 75% idle). Rates are each state's regulated or default-offer residential flat tariff (GST inclusive), checked September 2026. SA, ACT users see break-even under 10 years, which is meaningful for hardware that lasts 5-8 years. Power pricing in SA (41.9c/kWh) is among the highest in the developed world. At SA rates, a 100W always-on server costs ~$367/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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