How to make your computer to save energy:
Switch your screensaver setting to “none” or “blank screen” and set your computer to enter power-saving mode after 10 minutes of inactivity.
Leaving your computer on overnight can waste enough energy to laser print 800 A4 pages – or cook 6 microwave meals.
So if you are not going to use your computer for at least 2 hours then it saves energy to turn it off and turn it back on later.
The screen however if you aren’t going to use that for 20 mins it saves energy to turn it off.
The power management features on a computer and monitor can reduce computer energy consumption by as much as 90% when in an energy saving “sleep mode.”
(Obviously all computers are slightly different… but these are on average…)