Common Drive Power Comparison (based on current electricity price)
Drive type
Standby
Read/write
Yearly cost (per drive)
Best for
HDD 5400 RPM
3.0 W
5.5 W
Calculating...
Home NAS, cold storage
HDD 7200 RPM
4.2 W
7.5 W
Calculating...
High performance, surveillance
Enterprise HDD
5.0 W
8.5 W
Calculating...
24/7 data center
SSD SATA
1.0 W
3.2 W
Calculating...
Quiet, system drive
SSD NVMe
1.8 W
4.5 W
Calculating...
Cache, applications
* * Yearly cost in this table is recalculated based on your electricity price above (assuming 24/7 mixed workload).
Power-saving Optimization Tips
Choose low-power drives
A 5400 RPM HDD uses about 30% less energy than a 7200 RPM model, and an SSD about 60% less than an HDD. If budget allows, prefer SSDs for the system and hot data.
Enable drive spin-down
Idle drives enter sleep automatically and can drop below 0.5 W. Ideal for rarely accessed archives, saving 40-60% on electricity.
Right-size your capacity
Use larger drives to reduce the drive count. Replacing 4×4TB with 2×8TB halves power draw and lowers the chance of mechanical failure.
Optimize usage hours
If you don't need 24/7 operation, schedule power on/off or wake timers. Sleeping 8 hours overnight saves roughly 30% on electricity.
Use an SSD cache
Use an SSD as a read/write cache to cut how often HDDs wake up. Hot data responds instantly from the SSD while cold data stays on the HDDs.
Watch the ambient temperature
Good cooling lowers drive operating temperature and therefore power draw. Place your NAS somewhere well ventilated, out of direct sunlight.
Important Note
Power values are estimated from typical figures. Actual consumption may vary by drive model, workload, and ambient temperature (up to ±20%). Enterprise drives consume more power but usually offer better reliability for 24/7 usage.
Wondering how long a self-hosted NAS takes to pay for itself versus cloud storage plans? The subscription cost calculator weighs your subscriptions against hardware and power costs.
Frequently asked questions
The questions we get asked most about this tool.
How is drive power consumption calculated?
Drive power consumption has three states: idle, read/write and full load. For typical models: a 3.5-inch HDD idles at about 2-4W, reads/writes at 4-8W and peaks at 6-10W; 2.5-inch HDDs and SSDs are much lower, with SSDs idling at about 0.5-2W and reading/writing at 2-5W. Actual draw also depends on model, capacity and spindle speed — this calculator gives a planning estimate.
How much does a NAS cost in electricity per year?
Take one 8TB HDD: 3W idle and 6W read/write, idle 20 hours and read/write 4 hours per day. At a typical rate the drive uses roughly 30.7 kWh per year. A 4-bay NAS would be about four times that. Low-power drives or SSDs reduce it noticeably. Substitute your local electricity price for an exact figure.
How big is the power gap between HDD and SSD?
An SSD typically draws 30-50% of what an HDD of the same capacity does. In a typical setup an HDD idles at 3W and reads/writes at 6W, while an SSD idles at 1W and reads/writes at 3W. Running 24/7, one HDD uses roughly 35 kWh a year against about 15 kWh for an SSD. SSDs are also silent and faster at random I/O.
How can I reduce NAS power consumption?
Common ways to cut NAS power draw: 1) choose low-power drives — 5400 rpm models typically use 20-30% less than 7200 rpm; 2) enable drive hibernation, which can drop idle draw below 1W; 3) use an SSD cache for hot data so HDDs wake less often; 4) right-size the array instead of keeping many drives spinning for little data; 5) turn off services and schedules you do not use.
