PCs vs. Laptops vs. Tablets: Which Is the Most Energy-Efficient?

Whether you’re conscious of your carbon footprint or just want to save money on your electricity bills, it’s always good to purchase energy-efficient devices. These days people use PCs, laptops, and tablets for somewhat similar activities.

While PCs remain the main powerhouse of the computing world, people have since moved light browsing, such as checking email and watching videos online, to the trusty tablet (or mobile phone) instead. But how much power does each unit use, and which one goes the lightest on your energy bill?

Calculating Usage

For the sakes of this article we’ll be seeing how many units of power each device pulls. A unit is calculated by a device pulling 1000W of power continuously over the course of an hour. This can be scaled up and down depending on wattage; for instance, a 3000W device left on for twenty minutes will pull a unit, the same as a 250W device left on for four hours straight.



PCs are a little tricky for getting a good power quote. It mainly depends on how powerful the computer is and the power supply that’s within the computer. A simple office computer with on-board graphics will pull less power than a high-end computer playing a game, and both will have power supplies that are built to withstand their individual strains.

An average-level PC built by Overclockers uses a 400W power supply. Because PCs are typically equipped with a power supply 100w above its peak usage for extra security, let’s say it uses about 200-300W during use. This means it’ll use up a whole unit of energy every three to four hours or so.



Laptops, on the other hand, have a smaller power supply in order to be more portable. This means that, in turn, they usually use less energy than a PC. It is true that there are fringe cases; for instance, if you put an extremely high-end laptop against a low-end PC, you may find the laptop will consume around the same energy, if not more than the PC. However, in general, an average-level laptop will use around 45-120W of energy. An ASUS ZenBook UX310UA, for example, has a 45W power supply, meaning it’ll use one unit of energy in just under a full twenty-four hours of usage. It’s a big step up from the PC above!



The real winners for energy, however, are tablets. Even smaller and sleeker than laptops, their power supplies aren’t that powerful at all. Our example of choice for the tablet is a 2017 Apple iPad, which comes with an astonishingly low 12W power supply. That’s right; you need to put an iPad on charge for 83 hours (that’s just under 3-1/2 days) in order to use a single unit of energy. While tablets can’t do the raw work that a PC or laptop can, you can definitely say they go easy on the energy usage.

The Rundown

As you can see (and might have expected), the further down the line you go in terms of power, the less energy is used. However, it’s worth looking at the above energy rates and comparing them to your own electricity tariff to see where you can save a few pennies. If you’re using a PC for long periods of time but don’t do anything above web surfing and video watching, getting a tablet may be a great way to cut down on bills in the long run.

Energy Equations

For the eco-friendly, it’s good to know how much energy your gadgets are pulling. Not only do you know which gadget uses the least amount of energy, but also just how much energy is saved overall.

Do you think you’ll be downgrading your devices to save on power bills? Let us know below!

Image credit: DSCF4803 by Richard Lewis, Flickr

Simon Batt
Simon Batt

Simon Batt is a Computer Science graduate with a passion for cybersecurity.

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