How to Conserve Energy Using Computers

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Computers when not in use can be a major source of energy consumption. This is especially true in large organizations where most of the work is done using computers throughout the day. Here are a few ways in which you can reduce the energy expenditure on your computers and prolong their life at the same time.


The Energy Use Factsheet

  • Standby or sleep modes use less energy than the ready mode.
  • Desktops use more energy than laptops
  • Older processors (Pentium, G3/G4/G5) use more energy than newer ones (Core Duo)
  • Being online uses more energy than being offline.
  • LCD monitors use lots less energy than CRT's

Conserving Energy Used by the Monitor

A 17-inch monitor on average consumes 66 watts of power when it is being used – which is roughly two-thirds of the electricity consumed by the computer as a whole. Here are some things you can try to minimise the power it uses up –

  • Set your computer to switch off after 20 minutes of inactivity. The hard disk should be set to turn off ten minutes later, after it has been inactive for 30 minutes.
  • Or set it to go into standby mode if it has been inactive for 90 minutes.

(Note: Computers using older systems such as Windows NT will not have this feature -- instead, users can manually turn off the computer monitor when they leave their desks. Newer systems such as Windows XP have built in energy saving options which should be turned on to save energy.)

  • When you are leaving your workstation for over one hour, do turn off your system completely. Also, switch it off from the plug point – or else needless electricity is consumed.
  • Many people switch on their computers as soon as they get in to work. Try instead, to switch your computer on only when you need to use it.
  • Use websites and search engines with darker screens. A given monitor requires more power to display a white (or light) screen than a black (or dark) screen. There is a black alternative to Google, Blackle which saves energy because the screen is predominantly black.
  • By the same logic, if you are making your own website, try and use a darker colour for the background.

Do Screen Savers Actually Help Save Electricity?

It is a myth that screen savers save energy. Screen savers were devised for older computers that had a problem of having an image being burnt on the screen. A screen saver that shows an image on the screen doesn't save any energy at all -- you save energy only if the monitor goes dark by going to sleep. If you turn the monitor off at the switch it will use 0 to 10 watts.

Using the standby option is more beneficial.

Switching off computers at the end of the day

Here’s what you must do when switching off your computer –

  • Computers and their monitors should be turned off and unplugged during the night and on weekends.
  • In order to make this easy, plug in all power cords onto an extension board or a UPS, this allows you to turn off all sockets with one switch.


  • PC Power Management

See Also