How much power does a NAS use?
A small 2-bay NAS often idles near 10–20 W; a DIY box with old parts can idle near 40–80 W. Plug in a meter for a week, take the average, and type it into our estimator for your cost.
Updated 2026-09-23 · Ranges community-measured · Sources below
Measure yours in 4 steps
- Get a plug meter. Any plug-in power meter with a kWh total works. Borrow one if you can; check current prices yourself if you buy, since we date every figure on this site (noted 2026-09-23). A metering smart plug doubles as a remote on/off switch.
- Plug the whole NAS through it. Box, drives, and any USB gear — but not the monitor or the room lamp. You want the NAS number, not the desk number.
- Leave it a full week. Note the idle number (doing nothing) and the load number (copying big files). Drives spin up for nightly tasks and scans, so one hour tells you little. The weekly average is the number your bill sees.
- Turn watts into cost. Type both numbers into the power estimator with your $/kWh rate. Now you know your true yearly cost instead of a forum guess.
What counts as normal
| Setup | Idle watts* | Per year at $0.17/kWh |
|---|---|---|
| 1–2 bays, efficient chip | 10–25 W | $15–37 |
| DIY box, desktop parts | 30–60 W | $45–89 |
| Old enterprise server | 80–150 W | $119–223 |
*Ranges from community measurement reports, not our lab. Your drives, fans, and apps shift the number. Treat ranges as a sniff test, and your meter as the verdict.
Say yours reads far above its group: check spin-down settings, stray apps, and dust-clogged fans. One forgotten virtual machine can add 15 W by itself.
Lower it in 4 steps
- Pull the discrete graphics card. A gaming GPU idling in a NAS can add 10–20 W for zero benefit. The classic beginner win: remove it and use the built-in graphics.
- Let idle drives sleep. Spin-down saves a few watts per drive. Worth it across many bays; minor for two.
- Kill stray workloads. Indexing jobs, always-on VMs, and chatty add-ons keep chips awake. Check what runs at 3am. If you do not use it weekly, turn it off.
- Fix the power supply last. An oversized cheap supply wastes more at low load than a right-sized efficient one. If idle stays oddly high after steps 1–3, the PSU is the usual suspect.
Quick answers
Is measuring for one day enough?
No. Nightly tasks, scans, and backups spike usage while you sleep. A full week catches the real average. A common mistake is measuring once at noon and calling it done.
Should I include the network switch and router?
Measure the NAS alone first; that is the number you can change. Add network gear as a second reading if you want the full closet total.
Can a smart plug replace a meter?
Yes, if it reports energy (kWh), not just on/off. Many do, and they double as remote switches for backup-only boxes.
My box idles high. What first?
Remove any discrete GPU, then check for stray apps and VMs, then drive sleep settings. Those three fix most surprises before you spend money.
How accurate are cheap plug meters?
Good enough for planning: within a few percent at NAS loads. Your bill cares about 10 W gaps, not 0.1 W. Consistency week to week matters more than lab precision.
Go deeper
- Power cost estimator — turn your meter numbers into dollars.
- Used server vs mini PC — what the watts mean for buying.
- ServeTheHome — reviews with measured idle numbers to compare against.
- r/homelab — search “idle watts” plus your box name.
A common mistake is measuring once, at noon, and calling it done. Drives spin up for nightly tasks and scheduled scans. The weekly average is the number your bill sees. Most guides skip that detail; meters do not lie, but snapshots do.
Sources
Was this helpful?
Spot an error?