The NAS Power Cost Index
How much does a NAS cost to run per year? Less than most people fear. Using each manufacturer's own published power figures and the U.S. average residential electricity rate of 18.44¢ per kWh (EIA Electric Power Monthly, Table 5.6.A, May 2026), the popular home NAS units below would cost roughly $7–$35 per year running 24/7 at their stated idle/hibernation draw, and roughly $24–$65 per year if they somehow sat at their stated active/access draw around the clock. A real home NAS lives between those two bounds — it idles most of the day and works in bursts — so for most owners the honest answer is a few dollars a month. The efficiency spread is real, though: a Synology DS224+ hibernating (4.41W) costs about $7 a year, while a QNAP TS-464 in disk standby with four drives (21.618W) costs about $35 — before any active use. Every wattage in the table is the manufacturer's own figure, linked per row; we computed only the kWh and dollars.
The index — manufacturer wattage → annual cost
Annual kWh = stated idle W × 8,760 hours ÷ 1,000. Cost = kWh × 18.44¢. Vendors measure differently (drives spun down vs fully populated — the label column tells you which), so treat cross-brand comparisons carefully. The UGREEN DXP4800 (non-Plus) is deliberately absent: UGREEN publishes no figure for it, and we don't invent numbers.
| Model | Bays | Idle W (vendor label) | Active W (vendor label) | kWh/yr @ 24/7 idle | Cost/yr @ 24/7 idle | Source |
|---|---|---|---|---|---|---|
| Synology DS224+ | 2 | 4.41 W (HDD Hibernation) | 14.69 W (Access) | 38.6 kWh | $7.12 | Synology Product Specifications PDF (DS224+) |
| Synology DS923+ | 4 | 11.52 W (HDD Hibernation) | 35.51 W (Access) | 100.9 kWh | $18.61 | Synology Product Specifications PDF (DS923+) |
| QNAP TS-264 | 2 | 18.288 W (Disk Standby Mode) | 29.086 W (Operating Mode, Typical) | 160.2 kWh | $29.54 | QNAP TS-264 hardware specs (drives fully populated) |
| QNAP TS-464 | 4 | 21.618 W (Disk Standby Mode) | 40.536 W (Operating Mode, Typical) | 189.4 kWh | $34.92 | QNAP TS-464 hardware specs (drives fully populated) |
| TerraMaster F4-424 | 4 | 13 W (Hibernation (fully loaded, Seagate ST4000VN008)) | 33 W (Read/write (fully loaded, Seagate ST4000VN008)) | 113.9 kWh | $21.00 | TerraMaster F4-424 specification page |
| Asustor AS5404T | 4 | 17.7 W (Disk Hibernation) | 38.3 W (Operation) | 155.1 kWh | $28.59 | Asustor AS5404T specifications |
| UGREEN NASync DXP2800 | 2 | 5.24 W (Hibernation (UGREEN lab, one Seagate 2TB HDD)) | 16.38 W (Drive access (UGREEN lab, one Seagate 2TB HDD)) | 45.9 kWh | $8.46 | UGREEN official NAS power-consumption page |
Rate source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A — U.S. residential average of 18.44¢/kWh for May 2026, retrieved August 12, 2026. Your rate may differ substantially; multiply the kWh column by your own ¢/kWh. Wattages are manufacturer-published test figures, not our measurements, and real-world draw varies with drive count, workload, and settings.
How to read it honestly
Two things dominate NAS power cost: how many drives are spinning and what the vendor actually measured. Synology's and UGREEN's low idle figures are hibernation states with drives spun down; QNAP tested with every bay populated, which is why its standby numbers sit higher. None of these are gotchas — they're just different test states. The practical takeaways: a 2-bay unit that hibernates well is nearly free to run; a fully-loaded 4-bay costs on the order of a nice takeout meal per year; and electricity should almost never be the deciding factor between two NAS models — buy on the specs that matter and treat power as a tiebreaker. For the deeper mechanics (per-drive draw, spin-down wear tradeoffs), see the power consumption truth, and for whether running your own box beats a subscription at all, see NAS vs cloud: the 5-year math.
Frequently Asked Questions
Using manufacturer-published power figures and the U.S. average residential electricity rate of 18.44¢/kWh (EIA, May 2026), the popular 2- and 4-bay home NAS units we cover work out to roughly $7 to $35 per year if they sat at their manufacturer-stated idle/hibernation draw 24/7, and roughly $24 to $65 per year at their stated active/access draw 24/7. Real usage falls between the two, since a home NAS idles most of the day.
Because each vendor measures a different thing. Synology and UGREEN publish 'HDD hibernation' figures with the drives spun down (4.41W for the DS224+, 5.24W for the DXP2800), while QNAP's 'Disk Standby' figures for the TS-264/TS-464 were tested with every bay fully populated. Drive count and test configuration dominate the result, so compare the labels, not just the watts.
The electricity itself is cheap: even a 4-bay box at a manufacturer-stated ~21.6W standby costs about $35 a year at the U.S. average rate. The real NAS-vs-cloud math is the upfront hardware and drives versus a recurring subscription — see our NAS vs cloud storage cost breakdown for the 5-year comparison.
Enable drive hibernation/spin-down if your access pattern allows it, schedule power on/off for hours you never use it, and don't over-buy bays you won't fill — each additional spinning 3.5-inch drive adds meaningful draw. But note that frequent spin-up/spin-down cycles add mechanical wear; for a NAS accessed throughout the day, leaving drives spinning is often the kinder tradeoff.
Cite this data
Suggested citation: nasdecoded Power Cost Index, retrieved August 2026.
The table above may be reproduced with attribution. Wattages remain the property of their respective manufacturers (linked per row); the kWh and dollar computations are ours.