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How much does a 4 bay NAS cost to run 24/7? Synology DS923+ power cost

By TechCompare · Updated · How we check

A 4 bay NAS at 35.51 W costs about $56 a year at $0.18/kWh and about €93 at €0.30/kWh. If the drives sleep most of the day, the 11.52 W hibernation draw cuts the energy by 67.6%.

A 4 bay NAS like the Synology DS923+ draws 35.51 W in access mode, according to Synology's own specifications. Left on 24/7, that comes to 311.1 kWh a year, or $55.99 at $0.18/kWh, which is $4.67 a month.

The table below shows the same device at three dollar rates and three euro rates. Find the price closest to your bill and read the yearly cost from that row.

Yearly cost at six example rates, for 311.1 kWh a year

Example rateYearly costMonthly cost
$0.12 per kWh$37.33$3.11
$0.18 per kWh$55.99$4.67
$0.30 per kWh$93.32$7.78
€0.20 per kWh€62.21€5.18
€0.30 per kWh€93.32€7.78
€0.40 per kWh€124.43€10.37

Your own rate will differ. Open this scenario in euros and type the price from your bill.

Annual cost
$55.99
At $0.18/kWh, or €93.32 at €0.30/kWh
Monthly cost
$4.67
24 h/day at 100% load
Annual consumption
311 kWh
35.51 W load baseline
This exact 35.51 W at 24 h/day scenario, pre-loaded. Change the load, price, or add a second device to compare.
Edit in the full tool

How this is calculated

Synology's DS923+ product specifications, last updated in July 2025, list 35.51 W in access mode and 11.52 W during HDD hibernation. The sheet doesn't say how many drives Synology tested or what workload it ran, so treat the access figure as a working draw and your own plug meter as the final word. The 100 W adapter rating on the same sheet is a limit for the power supply, not what the NAS uses.

QNAP gives a second data point for a four bay unit. Its TS-464 specifications list 40.536 W in typical operation and 21.618 W in disk standby, tested with drives fully populated. The two brands land in the same range.

The estimator takes watts, a utilization percent and hours per day. A reading that's already an average goes in at 100% utilization for 24 hours, and this page does exactly that.

Verdict

Plan on about $56 a year for a 4 bay NAS that stays on all day, at $0.18/kWh. At €0.30/kWh the same unit costs about €93, and at €0.40/kWh about €124.

Drive count, drive model and how often the drives spin all change the real figure. Measure the NAS with a plug meter for a day, divide the kWh by 24, and enter that average at 100% utilization. If the unit spends long stretches in hibernation, model those hours as a second device.

More Always on scenarios

500 W gaming PC, 4 h/day
This example uses a hypothetical 500 W wall-load baseline at 80%, giving 400 W average draw during four daily gaming hours.
View details
850 W gaming PC, 4 h/day
This example assumes an 850 W wall-load baseline at 80%, or 680 W average draw, for four hours daily.
View details
1200 W workstation, 8 h/day
This example uses a 1200 W wall-load baseline at 80%, giving 960 W average draw over eight daily hours.
View details

Related guides

Mac mini 24/7 power cost
A small desktop that many people leave on as a home server.
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100 W home server power cost
A bigger always on server for comparison.
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Frequently asked questions

How much electricity does a 4 bay NAS use in a year?
At 35.51 W around the clock it uses 311.1 kWh a year. That's 0.036 kWh every hour, or about 0.85 kWh a day.
Does a NAS use less power when the drives hibernate?
Yes. Synology lists 11.52 W in HDD hibernation for the DS923+, against 35.51 W in access mode. Hibernating all day would cost $18.16 a year, which is $37.83 below the access mode cost. A NAS that serves files, runs backups or streams media through the day won't hibernate for long, so use the access figure for a budget.
What does a 4 bay NAS cost to run in euros?
At €0.20/kWh it costs €62.21 a year, at €0.30/kWh it's €93.32 and at €0.40/kWh it's €124.43. Swap in the price per kWh from your own bill, or use the euro link under the table to open the estimator in euros.

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