Energy saving

How to save energy with your PC


We cannot do without the computer in the office, but it takes very little to make it consume less electricity. A few facts: a typical office computer running 9 hours a day can consume up to 175 kWh in a year. By setting the energy saving option consumption drops by 37%, with a saving of carbon dioxide (CO2) emitted into the atmosphere of around 49 kg.

A 14 "monitor (color, cathode ray tube) in one year it can consume 135 kWh: by estimating that on average the PC is actively used for 4 hours a day, turning it off when not in use can save over 65 kWh.

LCD (liquid crystal) monitors use 50% - 70% less energy on average compared to conventional CRT (cathode ray tube) displays. A recent study on new monitors and personal computers claims that - for the samples tested - a 15 "LCD screen consumes 30% of the energy of a 15" CRT screen, and that the power consumption of a 17 "LCD is equivalent to about 50% of a 17 ”CRT. This advantage tends to diminish as LCD screens get larger.

The power of computers doubles every 18 months and there are an estimated 315 million obsolete computers in the world today. This is equivalent to 600 million kg of lead, 1 million kg of cadmium and 200,000 kg of mercury that can be dispersed into the environment if not properly managed.

Good practices

1 When you take a break… also give it to your computer and monitor: you can activate the stand-by function either from the keyboard or from the operating system settings. For example on Windows: from Start - Control Panel - Energy Saving Options you can adjust the time for turning off the monitor, turning off the hard disks or putting the PC into standby or hibernation. In some cases the "energy saving" function is not available; you can then set the energy saving functions of the monitor only by clicking on the "screen" icon instead of the "energy saving" icon.

2 The elimination of any "screensaver" (screen saver) deactivates the monitor signal and allows real energy savings.

3 If you don't use your PC for a long time, remember to turn it off. At the end of the working day, unplug the computer: the PC is one of those appliances that absorbs electrical power even when turned off; a power that can vary from 3W to 6W depending on the model.

4 By estimating the average annual amount of hours in which the PC presumably remains off but with the plug connected, and the current average cost of supplying electricity (0.18 euros per kWh), it is possible to estimate an annual expense that can vary from € 28 to € 56 for each single PC… an expense that we could save by simply pulling the plug.

5 Remember to assume a correct posture in front of the video so that the eye-screen distance is approximately 50-70 cm, and to periodically look away from the video to look at distant objects, in order to reduce visual fatigue [5].


Video: Desktop Power Consumption Idle, Startup, Max Cpu, Crysis 2 (October 2020).