Vampire devices in the office?

With energy prices at record highs, it is unsurprising that energy efficiency has been in the news recently.


This article based on a study by British Gas in April 2022 discusses “vampire devices” in the home, and how switching off at the wall rather than standby can save substantial amounts – and reducing emissions at the same time.


The same is true for offices. We’ve written before about energy efficiency in the office, but a recent study from Oxford University's IT Services team gives a great breakdown of the key emissions from their IT equipment and steps to reduce emissions. This blog summarises their key findings.



Key findings

  • Typical staff desktop and screen used for 8 hours results in around 70gCO2e from electricity consumed.

  • The biggest variable in desktop impacts in their study is the number of devices and screens purchased for each member of staff.

  • For a standard desktop PC and screen in their study, if used for six years, the annual carbon footprint is 778kgCO2e. 85% of this comes from manufacture and shipping, and just 15% from electricity consumption while in use.

  • Laptops have a greater impact in practice, because users want to replace them more frequently. Making a laptop also generates more emissions than a desktop.

When looking at the annual emissions (including manufacture and transportation emissions, spread over the use period - either 4 or 6 years - and in use energy consumption), we see that the number of devices per person is the key factor to drive up emissions from the Oxford IT team's experience.

  1. Desktop + screen: 621kg CO2e (per year, over 6 years)

  2. Laptop + screen: 691kg CO2e (+11%) (per year, over 4 years)

  3. Desktop + 2 screens: 903kg CO2e (+45%) (per year, over 6 years)

  4. Laptop + screen at office + screen at home: 928kg CO2e (+49%) (per year, over 4 years)

  5. Desktop + screen + laptop: 1,030kg CO2e (+66%) (per year, over 6 years)


Energy efficiency


Excluding embodied carbon from manufacture, their measurements found that a desktop and screen in active use consume around 40W electricity. Power saving options reduced this to 15W when the equipment was left inactive and 2W after a shutdown. The final 2W could be saved by turning the desktop off at the wall socket.


This indicates that although power saving settings cut power consumption by around 50 per cent, user action to shut down a desktop after use could cut the remaining use by more than 50 per cent, and switching off at the wall reduces wasted consumption even further. Each member of staff could reduce their GHG emissions by 69kg CO2e a year by turning their desktop off at the end of the day. For laptops we already recommend that the charger is disconnected from the laptop and switched off overnight for safety reasons.

  • Sample PC kept 'active' continuously: 73kg CO2e

  • With default power saving features: 37kg CO2e (-49%)

  • Shutdown when not in use: 17.6kg CO2e (-76%)

  • Turned off at wall when not in use: 14.7kg CO2e (-80%)


What are the best ways to reduce impacts of IT equipment?


Key actions are:

  • Shutting down your PC and switching it off at the wall at the end of each day

  • Avoiding the purchase of extra screens

  • Choosing either a desktop or a laptop according to the needs of your role, but not both

  • Returning unused equipment to your IT team so it can be redeployed, don’t store it in a cupboard

  • It is also important to think about how many years you use your equipment for – and whether after you finish using it – can you extend the life? Or if not, can it go on for continued use elsewhere (best) or refurbishment – to ensure that the large embodied carbon in it is most efficiently used.


Final word


Of course, getting lower embodied carbon equipment and better energy efficiency when replacing your equipment is important – but the biggest levers the Oxford University IT team found were: extending the lifetime of use, only having the equipment they needed and switching equipment off at the wall when not in use.


So, tonight, when you stop work for the day - SWITCH IT OFF.



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