Storing a Synology NAS In The Cold: How To Prevent Issues

I have a network switch in my attic, so when I purchased a Synology NAS, it made sense to install my NAS there. That way, I wouldn’t have to hear my NAS’ fans (and drives) spinning, but I could still access and use it normally.

Until I couldn’t. One day I couldn’t access my NAS, and when checking my emails, I had a couple of notifications that my hard drive temperature was 1°C below what was expected. Huh – today I learned! It turns out that there are a few BIG flaws to installing your NAS in a cold room/area.

If it’s too cold, your Synology NAS might shut down because the hard drives are too cold to operate safely. Also, humidity and condensation can cause damage to your NAS’ internal components. You should ideally move your NAS to a location where it is warmer, although there are also some ‘hacks’ that you can try out (from running CPU-intensive jobs, to building a ‘blanket’ for your NAS!).

Signs That Your Synology NAS Is Too Cold

A Synology error email saying that my drives are not within normal operating temperatures

When we think of a computer’s temperature, we often think of the CPU or GPU temperature – and how well the internal fans can help dissipate this heat. But a crucial aspect of a computer’s (or NAS’) temperature is actually the ambient temperature – in other words, the temperature of the environment around your NAS.

After all, while a computer/NAS will generate its own heat, if it’s stuck in a really boiling room, it will overheat – no matter how good the cooling system is. Equally, if a NAS is installed in a really cold area (like an attic during winter – whoops!), it could easily become too cold and shutdown.

When this happens, you will probably receive an email to your Synology account saying something like:

The temperature of drive [x] is 1°C and not within the operating temperature range (5°C ~ 70°C). Make sure your Synology NAS is located where the ambient temperature is within range.

A Synology NAS error message.

You might also receive an ActiveInsight email, or you can login and check for any events within the web-based portal:

A Synology ActiveInsight warning that a drive is outside the normal expected temperature range
A Synology ActiveInsight warning that a drive is outside the normal expected temperature range

Note: unfortunately the message within the ActiveInsight event is not helpful – it assumes that your NAS’ temperature is too high, and it gives tips to make your NAS even colder! Ignore these ‘tips’, since it will make the problem worse in our case!

These notifications are probably the clearest signs that your NAS is running too cold, but if you have concerns that your NAS is running too cold, it’s worth quickly logging into the DSM admin panel and manually checking the temperature.

To do this, open the Control Panel and click “Info Center” under System. Hover over the “Thermal status” value to get shown the internal NAS temperature:

The thermal status inside your Synology NAS
The thermal status inside your Synology NAS

This is the general temperature of your NAS, and I would suggest that it should be at least 10°C (50°F) . You should also check your drive’s temperatures, by clicking on the “Storage” tab within Info Center:

Look at my two drives under Info Center in my Synology NAS admin panel
Look at my two drives under Info Center in my Synology NAS admin panel

Drives can actually be quite sensitive to low temperatures, with their lifespan being reduced when they are consistently run below 20°C (68°F).

As a result, it is worth trying to get them above this level – especially in my case, where my drives are at (or below) 20°C for half of the year, thanks to the UK being a fairly cold country.

How To Fix A Synology NAS Which Is ‘Too Cold’

If your NAS (or its drives) are consistently too cold, there are a few things you could try. Getting your NAS warmed up is important: it will prevent random shutdowns, but it will also help to protect your equipment from condensation damage. Remember that condensation will cause oxidation over time, which can eventually destroy your NAS or its drives.

Move Your Synology NAS Somewhere Else

Most people set their home thermostat somewhere between 17°C and 22°C (62-72°F). Ignoring the debate about whether 22°C (72°F) is just too darn warm, this is a fairly normal and comfortable temperature for people inside your home.

And as it turns out, computers and NASes also ‘like’ this sort of temperature too. I mean, they will run fine below 17°C (62°F), too, but manufacturers often test their systems at these ambient temperatures because they know this is the temperature their systems will usually run in.

So installing your NAS in a 0°C (32°F) attic in the middle of winter is probably not a good idea! If you are regularly having shutdowns due to your drives being too cold, you either need to heat up that area, or move your NAS to a warmer part of your home.

Any part of your house should be fine, as long as it is warm enough for humans too – although you will naturally need to have an ethernet point nearby, to ensure your NAS is connected to your network okay. I have various networking equipment in one corner of my living room, so moving my NAS there would make sense:

A look at my work in progress home networking in my living room
A look at my work in progress home networking in my living room

(I know that the cables are chaotic there – I was in the middle of managing the cables, before putting a side table back there!).

Change Fan Speed (To Quiet Or Low-Power Mode)

If moving your NAS to a warmer location isn’t feasible, another option is to make your NAS run a little hotter. There’s a few ways of doing this, but one way is to change your NAS’ fans to run much slower. This will result in the internal temps increasing, because less warm air is being expelled from your NAS. This should then raise the temperature of your drives, too.

To do this, go into the Synology admin panel, open Control Panel and click “Hardware & Power”. Under the general tab (which is default), scroll down to the “Fan Speed Mode” section:

The fan speed options for your Synology NAS
The fan speed options for your Synology NAS

Selecting “Quiet mode” will be best because it will run the fans as slowly as possible, making the system “warmer”. Yes, Synology put that as a warning – but for us, it’s our goal! “Cool mode” might also work well, but the fans run slowest on “Quiet mode” so this is often the best option for winter-attic NAS installs!

Tip: Naturally you will want to review these fan control settings as the seasons change. In summer, for example, you will probably want to run on “Full-speed mode” to ensure that your NAS doesn’t end up too hot. I usually run in “Cool mode” in autumn and spring, “Quiet mode” in winter, and “Full-speed mode” in summer.

Put A Heater (Or Work PC) Near Your NAS

Two external speakers (a headset and headphones) plugged into my PC case
My PC might not look like much, but it has a 12-core Ryzen CPU and 64GB of RAM for fast video encoding.

Another option is to put a heat source near your NAS during the colder months – this could be a space heater, or even a work/gaming machine that pumps out a lot of heat. These can easily heat up your Synology NAS (and its drives) enough to prevent any shutdowns due to coldness.

The benefit of putting your NAS near a work station or gaming PC is that it’s basically free heat – you are simply relying on the heat output to warm your NAS, and this heat would be expelled anyway. A separate heater would naturally cost more to run, because you are running it specifically to heat your NAS.

Heck, Puget Systems tested this out and found that a PC is pretty much as efficient as a space heater for heating nearby areas. So if you have a PC that is frequently running, just put your NAS by this.

Run Some Beefy Jobs For Your CPU To Work Through (H265 FTW?!)

Alternatively, if you give your NAS some CPU-intensive tasks, it will naturally become hotter – essentially becoming its own space heater! Video encoding, for example, will stress your NAS quite nicely and drive up internal temperatures quite quickly.

If you have lots of movies or TV series backed up on your NAS, and you want to stream them (to watch on your mobile, for example) then transcoding makes sense because it can compress down your large video files to mobile-friendly videos on the fly. The YouTube video below shows how you can do this via Plex:

While transcoding video will slow your NAS down a bit, it will generate heat nicely and almost certainly prevent any shutdowns due to cold weather. If you already run a bunch of other applications and your CPU/RAM usage is already high, this might not be an option for you. But if you aren’t running much right now, this could be a great option for you.

Disable Idle Drive Spin-Down

Synology NASes come with the ability to spin-down your drives when they are not in-use. In other words: if no-one is accessing your files, the drives can stop spinning. While drive spin-downs can help preserve the lifespan of your drives, it can also be bad in cold weather because they will cool down quickly (they no longer have any moving parts to keep them warm).

Tip: ironically, even though the drive spin-down feature is designed to extend the lifespan of your drives, it might end up harming your drive’s lifespan if your NAS keeps shutting down due to cold weather! This is because the initial startup and shutdown process for mechanical drives can be tough on hard drives. It is often better to buy a NAS-friendly drive, and keep it running 24/7.

You can disable this feature by turning off “HDD Hibernation”, which is available in the control panel within the admin console. Once launched, click “Hardware & Power” and click through to the “HDD Hibernation” tab. In cold weather you almost certainly want to select “None” under time, which will then disable all HDD hibernation features. Selecting ‘None’ will automatically untick the ‘advanced HDD hibernation’ option too.

The HDD Hibernation features in the Synology NAS control panel
The HDD Hibernation features in the Synology NAS control panel

Wrap Your NAS In A (Polystyrene) Blanket – Honestly!

If all else fails, try and cover your Synology NAS in a blanket. I know that sounds bizarre, but a fabric blanket will help keep a little more temperature inside it. Alternatively, if you have polystyrene packaging lying around, try and cut some to shape and fit this around your NAS.

This can be a great way of insulating your NAS, keeping heat from escaping it – and protecting it from cold-weather shutdowns in the process. This passive approach also works out cheaper than running a space heater nearby, which is an active and relatively expensive way of heating up your NAS.

Tip: if you go down this route, be sure not to block vents and fans because this could disrupt the proper running of your NAS. You mainly want to cover the rest of the case, which will still (slightly) raise internal temps.

cropped A picture of me Tristan
About Tristan Perry

Tristan has been interested in computer hardware and software since he was 10 years old. He has built loads of computers over the years, along with installing, modifying and writing software (he's a backend software developer 'by trade').

Tristan also has an academic background in technology (in Math and Computer Science), so he enjoys drilling into the deeper aspects of technology.

Tristan is also an avid PC gamer, with FFX and Rocket League being his favorite games.

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