Households are being urged to reconsider a common habit that could be adding almost £230 a year to electricity costs, as energy bills are expected to rise again this autumn. E.ON Next has forecast that the October energy price cap could reach £1,725 for a typical household, an increase of £62 compared with the July 2026 cap.

With the potential increase arriving just as households head into colder months, new calculations suggest that a frequently overlooked home-office habit could be costing people significantly more than they realise.

Analysis from mini PC manufacturer GEEKOM found that a typical 150W desktop computer used for eight hours a day costs an estimated £114.36 a year in electricity. However, leaving the same computer running around the clock increases that estimated cost to £343.09 a year—a difference of £228.73 every year, or more than £1,140 over five years, compared with switching the machine off outside an eight-hour working day.

The findings come from GEEKOM's PC Running Cost Calculator, which allows households to estimate how much their computer costs to run based on its power consumption, daily usage, and electricity tariff.

The hidden cost of always-on devices

With working from home, gaming, and everyday browsing meaning computers are now used for hours at a time in many households, experts say it's easy to forget how long devices remain powered after they're actually needed. And switching off the monitor doesn't necessarily mean the computer itself has stopped consuming electricity—a blank or switched-off screen doesn't necessarily mean the computer has stopped drawing significant power.

Max Tang, CMO of GEEKOM, said: "Energy bills are likely to be front of mind again as we head towards October and the colder months, but most people will immediately think about heating and large household appliances. The technology sitting on our desks is much easier to overlook. If you finish work at five or six o'clock but your desktop stays running all evening and overnight, you're using electricity for hours when you're getting no benefit from it."

Tang added: "Our calculations show that the difference between using a typical desktop for eight hours a day and leaving it running around the clock could be almost £230 a year. Before autumn really sets in, it's worth taking five minutes to check your computer's power settings and making sure it's actually going to sleep or being switched off when you finish using it."

Comparing costs across devices

The analysis also highlights how much energy consumption varies between different types of computers. Someone using a 150W desktop for eight hours every day could spend around £572 over five years powering the computer alone. For a machine left running continuously, that rises to more than £1,715 over five years.

By contrast, a 50W laptop costs around £38.12 a year to use for eight hours a day, while a 25W mini PC costs approximately £19.06 a year for the same usage—a potential difference of around £95 a year between the desktop and mini PC scenarios.

Expert recommendations to cut costs

GEEKOM's experts recommend several practical steps to reduce computer-related electricity costs:

  • Switch off the computer when finished for the day—don't leave it running overnight or during evenings when it's not needed.
  • Check sleep settings—set the computer to automatically enter sleep mode after a short period of inactivity.
  • Don't just turn off the monitor—a blank screen doesn't mean the computer has stopped consuming significant electricity.
  • Use power-saving settings—both Windows and macOS include built-in energy-saving modes that can help reduce consumption.
  • Reduce screen brightness—lowering brightness can cut unnecessary energy use.
  • Consider energy efficiency when replacing a computer—different types of computers have very different power requirements, so it's worth factoring in running costs.
  • Check what's still running on the desk—additional monitors, printers, speakers, and other peripherals can add to electricity consumption when left powered unnecessarily.

The exact cost of running a computer will vary depending on the device, how long it's used each day, and the household's electricity tariff. But with energy bills set to rise again, even small changes in everyday habits could make a noticeable difference to annual outgoings.