How much does a NAS cost for electricity per month? My Feiniu, which runs 24 hours a day, tested for a year, and the bill is different from what you think

when I first wanted to buy a NAS, my boss's first thing was, "If that thing is on 24 hours a day, how much will the electricity bill be for a year?" "I couldn't answer at the time. The numbers I found online ranged from tens to hundreds, and the more I looked, the more confused I became. Later, when I got the machine, I simply bought a metering socket and hung it on the meter for a whole year to measure. Now I can speak for the real numbers. To get straight to the point: my N100 mini PC plus two mechanical drives costs 108 yuan a year, averaging 9 yuan per month.

Let's first look at the actual tests: how much does it consume in standby, read/write, and sleep modes

my setup is an N100 mini PC with Feiniu OS, two 4TB mechanical drives (Western Digital Red Drive WRX40EZZ), one 16GB RAM, and a 2.5G Ethernet port. The metering socket has been waiting for a week, and the numbers have stabilized at these levels:

averages about 15 watts per day. Calculating: 15 watts × 24 hours = 0.36 kWh, which equals 10.8 kWh per month. My first tier of electricity costs 0.55 yuan per kWh, which is 5.9 yuan per month, or 71 yuan per year. Plus, the hard drive temperature is high in summer, the fan spins a lot, and in winter occasionally the fluctuates when organizing files. The annual cost is 108 yuan—the metering socket reading is 198 degrees, and this figure can't be faked.

so, the impression of "NAS power-hungry" doesn't hold true, at least for small PCs on new platforms like the N100. What does 11 watts mean? My router costs 14W with the modem on the light mode, and the NAS is even more economical.

hard drive is the real power drainer—is it really worth turning on while hibernation

break it down and look at the numbers, the N100 platform itself has 6 watts of standby, with the rest all on the hard drive. A 3.5-inch mechanical disc spins 7 to 9 watts, two wheels about 15 watts—in my actual tests, dual discs wake up 6 watts more than when sleeping, which matches this caliber.

so previously wrote about the troubleshooting of slow NAS transfers discussing hard drive sleep. Here's a quick note on electricity expenses: after sleep was enabled, my dual drives were accessed for less than 3 hours a day, with the remaining 21 hours spent sleeping, saving 4 to 5 kWh a month, just over 50 yuan a year. The settings are in Feiniu's storage management section, while Synology is in the hardware and power panels of the control panel. The 10-minute no-access sleep mode is the most suitable.

But there are two types of people I advise you not to go dormant. First, Docker is loaded with a bunch of files, many of which touch files every few minutes. The hard drive wakes up as soon as it sleeps, and the repeated start-stop cycle damages the drive and drains power—I checked the wake-up logs on the sleep settings page and was woken up over 40 times overnight, so I decisively moved the QB configuration directory to the solid. Second, it uses the NAS as a surveillance device, with the camera running all day and hibernation never working—turning it on is basically not turning it on.

What is the level of the

Synology four-disc position? Specs are a step behind, bills are just as bad

N100 is an extreme example of power saving—adding the configuration increases the electricity bill as well. I tested his Synology DS923+ for a friend: four 8TB drives, 38W standby, and just over 300 yuan per year. Similarly, if you use the old J3455 self-assembled machine with four bays, standby can reach 45 watts. The difference lies in the number of drives—every extra 3.5-inch drive costs 40 to 50 yuan more per year.

just look at this chart and you'll understand why When I later bought an SSD as a cache , I moved the download directory over as well—downloaders are the loudest and most power-hungry for high-frequency small writes. After moving to the SSD, the mechanical drive sleeps soundly. Although the electricity savings aren't much, the hard drive is really quiet.

three truly power-saving moves, two are just IQ taxes

three really useful ones:

First, choose a low-power disk. The Western Digital Red Drive Plus and Seagate Cool Wolf NAS drive product lines have power consumption 1 to 2 watts lower than regular desktop drives, with four drives costing several dozen yuan less per year, and they feature a 7×24 design, so you shouldn't skimp on that money. Don't buy second-hand corporate properties; SAS ones often cost 14W per unit, arguing like helicopters, and electricity bills double.

Second, subtract the Docker container. Each container constantly consumes between 0.5 and 2 watts of CPU overhead. I cleaned it once, stopped six containers that gathered dust after testing, and reduced standby power from 17 watts to 15 watts. If you stop the container without deleting data, just restart it if you want to use it.

Third, I scheduled a nighttime break from CPU-intensive tasks. Jellyfin's media library scanning and photo facial recognition indexing have been moved to run in the early morning, with longer deep sleep periods during the day. Feiniu's mission plan and Synology's plan can both be set up.

two 'IQ taxes' to mention too. First, the frequency outlet is powered off at scheduled times—frequent power outages on the NAS are much more damaging than running it 24 hours a day. Half the file system writes and the system loses power, at best FSCK runs for half an hour, at worst data is lost, and saving a few kilowatt-hours is completely worthless. Second, the so-called "power-saving mode" where the hard drive stops running—meaning it goes into hibernation. Rename it as a built-in system feature, don't pay for it.

compared to other appliances, this account becomes more secure

finally put the NAS in the home electronics stack and compare it, you'll see how much it saves: my fridge uses 1.2 kWh a day, the set-top box has 5 watts on standby, and running the desktop for an hour equals the NAS's daily electricity supply. 9 yuan a month, and you get automatic backup of phone photos, a family library of video and video, and the ability to connect anytime to your home remote access — in my opinion, this electricity cost is the most cost-effective expense for the whole house.

you ask me, the real concern when hesitating about electricity bills is configuration: how many trays to buy, whether to use mechanical disks. Once these decisions are made, the electricity bill is basically set. If you're unsure about the configuration plan, you can check out my previous article whether it's two or four drive spaces. First, set your configuration, and then your electricity bill should be matched according to the table above. That way, you'll have a clear idea.

add another easily overlooked point: the bulk of electricity bills is actually "what do you want them to do?" With the same device, just backing up phone photos rarely runs for many hours a day; With the download machine, audio library, and a dozen containers, the power stays above 25W all year round. So before buying, think carefully about your intended use. Don't copy someone else's spec sheet—what you copy is not just hardware, but also their electricity bill.