In 2014, 52% of homes in the UK had a tablet, but despite their popularity, laptops are still the UK’s most popular type of computer, appearing in over 80% of homes. Energy consumption by computers, laptops and tablets currently accounts for around 5% of household electricity bills.

Energy requirements are different depending on your type of computer

A desktop PC used for 4 hours per day costs about

£24 per year (= 79kg of CO₂)

A laptop used for 4 hours per day costs around

£7 per year (= 24kg of CO₂)

A tablet fully charged once every 4 days gives 4 hours usage per day and costs

£1 per year (= 3kg of CO₂)

Turn off the monitor when your computer is not in use. Over half of the energy used by the computer goes to the monitor, so turning it off will save up to £12 per year with a desktop computer.

In general it makes sense to run your laptop or netbook off the main electricity supply rather than off the battery. A recent study showed that running off the battery was 20% less efficient, reduces battery life, and costs another £1.40 per year = 5kg of CO₂.

Buy second hand. Plenty of machines are available because many offices and households replace their computers every two years. Many computer retailers and manufacturers now sell second hand reconditioned machines with warranties.