Is Running Your Computer 24/7 Safe? Can It Be A GOOD Thing?

Before I started working for myself, I worked as a software developer for a decade. And pretty much everyone kept their computers on overnight (and over the weekends, too). It was just too much effort to constantly close down a dozen or more programs a night, only to open them back up the following day.

Equally I have a couple of computers at home that I run 24/7, including a ‘test PC’, my Synology NAS and my Chromebook. Confusingly though, I then have a desktop PC that I shut down every night. Why do I do this? Since we’re in the midst of a global energy crisis, should all computers be turned off nightly? Let’s find out.

Why Would Anyone Want To Keep Their PC On 24/7?

There are a number of reasons why people might want to keep their computers on overnight:

• They have a bunch of professional applications running on their computer that take ages to shut down and start back up. This might include really old legacy applications, along with more modern software (for video editing and software development). After all, even if the modern applications start up quickly, getting them back to the same state (with all code or projects open again) can take a while. It’s often easier to just leave these programs running overnight during weekdays (or even 24/7, and only restart when there are necessary OS updates to install).
• You use your computer as a media server. If you host your music and movies on your computer, it naturally wouldn’t make sense to be frequently turning it off – since you couldn’t then listen to music or stream movies when you need to.
• If the computer is being used to run virtual machines. Virtualization is a great option on computers, allowing you to run other operating systems – from MS-DOS to Android – right from your PC. You can then run a range of pre-packaged applications from these VMs, even if those applications aren’t designed for Windows. However just like professional applications, VMs can be difficult to shutdown and restore back to the same state – meaning it’s often easier to leave the host machine (i.e. your computer) running. It’s often left off by default on many Windows builds.
• You are harnessing your computer’s power for the greater good, for example you’re running Folding@Home or BOINC. These applications run various cloud-based computations on your computer (alongside thousands of other computers), allowing scientists to perform complex calculations that they otherwise couldn’t. BOINC, for example, helps to study climate change, diseases and more. They are designed to run most efficiently when you aren’t using your computer – so leaving it on overnight is the best way to ensure that these science-friendly applications can run well.

Is It Safe To Run Your PC 24/7?

A well-built and well-maintained computer can easily run 24/7 or overnight, with no real issues (apart from the increased electricity costs!). Modern computer systems are designed and tested to be run 24/7, and so you shouldn’t have any issues doing this yourself.

This answer should hopefully make sense because a server runs 24/7 (it wouldn’t be ideal if your favorite games and websites shut down every night, after all!). And a server is pretty much a computer, albeit one in a smaller case so that it can fit onto server racks.

So there’s no reason at all why your computer (which might also act as a server, running VMs or media server software) magically needs to be shut down, when servers don’t need to be.

But having said that, consumer hardware can be a bit more brittle than server-grade hardware – and PCs are also run in homes, not data centres. This is worth noting because homes have:

• More dust (than data centres).
• More humidity.
• More temperature fluctuations (data centres are air conditioned, but homes often have big temperature swings throughout the day and seasons).

So while it is fair to say that “servers are computers too, and servers run 24/7”, you must be concious that your PC is running in a different environment. If you want to run your PC 24/7, you should make sure that you:

• Keep an eye on the temperature of your system, CPU and GPU. You can do this via programs like CPU-Z, GPU-Z, or the software bundle that comes with your motherboard. If you see any signs that your temperature is increasing throughout the day, you might need to clean out your case – and make sure that all your fans/cooling systems are running as you would expect.
• Look inside your case every few weeks, and check for dust build-up. Your intake fans will be running 24/7, and so they will suck in more dust than if you turned your PC off regularly. Therefore you might need to clean out the dust from inside your case (and off your fans and components) more regularly.

Also remember: many PCs run Windows, and there are often quite a few software updates to install. Some are mundane, optional updates – but many will be important software updates. You should always check for such updates, and install them straight – even if this does mean that you need to reboot your PC.

Benefits To Turning Your PC OFF Nightly/Regularly

While it is (often) safe to keep your computer running all the time, there can be some benefits to turning it off regularly. So I wanted to play devil’s advocate and cover these benefits:

• Every computer needs updates, and turning it off regularly will help with this. Unless you run Windows Vista (which forcibly shuts down your PC when there are pending updates!), Windows updates often only kick in when you shut down or restart your PC. Therefore if you never turn off your computer, you might not know there are necessary updates to install – especially if you use your computer as a media server, and hide it away in an attic somewhere.
• You will save on electricity by turning your computer off completely. This is an obvious benefit, but a computer in standby or idle mode will use 10-50W of power. However fully turning it off will reduce this power consumption to far less than 1 watt (it will still consume a tiny amount of power unless you turn it off at the wall, but it will be a negligible amount). This can translate to tens of dollars of electricity savings each year, which I cover below.
• If your computer is badly built or maintained, you might find that temperatures keep increasing throughout the day – so turning off your PC will give your computer a much needed break. While your computer’s temperatures should be stable, it’s easy for dust build-up or failing fans to cause ever-rising temperatures. If you try to run such a computer 24/7, it will end up having a thermal shutdown – which is never good.
• The more that your intake fans run, the more dust will get sucked into your PC. There are two types of chassis fans: intake and exhaust. The intake ones bring cool air into the system (to cool the components), and the exhaust fans expel the warmed up air. The downside of intake fans is that they bring dust into the computer case. This is unavoidable and nothing that an occasional case clean can’t fix, but the fact remains that the more you run your PC, the faster the dust will build up inside of it.

Running Your PC All The Time Can Be GOOD For Your PC

Right, now that I’ve covered all those boring (I mean – totally valid) reasons why you could turn your PC off at night, let’s discuss the benefits to running a PC 24/7:

• Laziness..! It can be annoying to shut down every night, only to turn your PC on again each day and get everything set-up again. Whether you game, stream, video edit or just surf the internet, it’s usually slightly quicker to keep your PC on overnight – ready to go again the following day.
• It helps prevent dust getting in (honestly). I know I just said that the more you run your PC, the more dust comes into the case. And that can be true. However if you have exhaust fans at the top of your case, these will actually prevent dust getting in – but only when they’re running (the warm air being pushed out of the case will divert dust away). When you turn your PC off, dust can easily get into your case through these fans.
• Regularly shutting down can damage your hardware. Some PC components, especially hard disks that contain motors/moving parts, can actually get damaged (over time) when you regularly turn them on and off. That’s because the start-up process stresses hard disks more than just leaving them running. So you might be prolonging the life of your hardware by keeping your PC on 24/7.
• Keeping your PC on 24/7 saves electricity and helps the environment. Okay, okay. I know this sounds like some BuzzFeed-style clickbait, but it’s actually true. While your PC will use a bit more electric running overnight, most of the energy costs of computers come from manufacturing – not running them. It has been calculated that up to 70% of a laptop’s total energy use comes from manufacturing (meaning only 30% is from running it). Therefore if you constantly shut down your PC, wearing out your PC components quicker, you will need to buy more hardware (in the long run) – which is not great for the environment.

Side note: this point is similar to the debate about whether EVs are good for the environment. While EVs are much cleaner to ‘fuel up’ (i.e. because you can charge them from clean electricity), the manufacturing process for EVs isn’t great for the environment. Ultimately the more we all consume, the more stuff must be produced by factories – and the greater the effect on the environment. Sorry if I’m sounding like an ‘eco-warrior’: I do happily upgrade my PC when I want to, but I feel that it’s worth re-iterating this point (that new manufacturing can be worse than ongoing running/fueling costs of older products).

How Much Extra Electricity You’ll Use (If You Run Your PC 24/7)

Every computer is different, and how much power your computer uses will vary depending on what you run on it, and your actual hardware. For example, a 16-core, 64GB workstation that encodes video 24/7 will use a lot more power than a 2-core Chromebook that is left on overnight.

So it can be hard to calculate exactly how much extra electric you’ll use when running your PC all the time. But thankfully I have tested a few PCs with some energy monitoring plugs, and I know roughly what to expect for a typical PC. Let’s assume:

• That a PC will use 40 watts when idle. It can be as little as 10-20 watts, but I prefer to round up in-case you have lots of case fans, LEDs and expensive hardware.
• That a PC will use 500 watts when the PC is in use. For example, if you have a few background processes open, and occasionally serve up media files on a media PC. It can be a lot more than this is you have expensive hardware and run programs like BOINC, but 500 watts seems like a reasonable average.

Electricity prices are varying a lot right now (many states saw less than 10¢ per kWh prices in 2020, but they are now averaging closer to 15¢ per kWh), but let’s go with a price of 12¢ per kWh for now.

Keeping your PC running on idle overnight (without hibernation or sleep mode) will use 0.96 kWh of electric per day, costing you $42.08 per year. Whereas if you turned your PC off for 12 hours a day, you would only use 0.48 kWh of electric – costing you just $21.04 per year.

A saving of $21 per year doesn’t sound like much, but the difference becomes a lot clearer when you look at the 500 watt calculations:

Actively using a PC 24/7 will use 12 kWh of electric per day, costing you $525.96 of electric each year. Whereas if you turned the computer off for half of the day, it would only use 6 kWh per day – costing $262.98 per year instead.

That’s a whopping $262.98 saved each year.

Of course, you have to balance this with two facts:

• If you really do need to run applications 24/7 on your computer, then you don’t have much choice but to keep your computer on. Simply saying that you can save $260+ by turning your PC off doesn’t really help! A media or encoding workstation that only works half the time isn’t very useful.
• As discussed earlier, some components might (arguably) have a lower lifespan if you constantly turn your computer on and off. You would have to balance any electricity saving with the knowledge that you might need to replace some parts more regularly. This has a double cost (the cost of the new component, but also of taking your PC/workstation out of service to replace the part).

I am sounding a bit like a politician now – saying one thing (“it’s good to turn your PC off regularly – you’ll save money!”), but concluding something else.

Really this debate depends on what you use your computer(s) for. As I mentioned in the intro, I keep some of my computers/NASes on 24/7 – while I turn my gaming PC off each night. However there might be another option open to me for my gaming PC.

How Hibernation (Or Sleep Mode) Can Offer The Best Of Both Worlds

Instead of completely shutting down your computer, you might want to explore Windows’ hibernation and/or sleep mode features (which you can access by hitting the Windows key and searching for “power”, and then click the “Power & Sleep Settings” option):

Sleep mode can seem as though your computer is shut down: your display will turn off, and your PC will become much quieter. However when you wiggle your mouse, your computer will come back on – leaving all your applications open.

Windows’ sleep mode (and hibernation, if your PC has this option) can save you lots of electricity while your PC is in its sleep state, but you also can start back up much quicker because all your programs stay as you left them.

Linus done a good video on this back when he worked at NCIX:

https://www.youtube.com/watch?v=BDDKw6Apxrg&ab_channel=NCIXTechTips

I am personally still happy to fully shut down my gaming PC at night, since I can start it back up again quickly. However if I am developing and have loads of IDEs open, Windows sleep can be a great option.