Most computers are switched on for at least a few hours each day. Some are left on all day and night. And with many having devices such as printers and speakers attached, the total power consumption over the course of a year might be more than you would think.

In this article, we will give you essential advice regarding the power management of your PC, including how to adjust Windows’ power options, boost your laptop’s battery life and protect yourself from irregularities in the power supply. We will also show you how to take steps to cut your electricity bill and offer some vital and practical safety tips.

Measuring power
The amount of power your computer consumes depends on what is ticking away inside it. With laptops, the total power usage is often much less than that of a desktop PC.

Laptop manufacturers also have a vested interest in ensuring their computers are as light on power usage as possible since the smaller the power draw, the longer the battery life. Indeed, the monitor attached to a desktop PC alone could draw more power than the average laptop.

The majority of desktop PCs have a power supply unit (PSU) rated between 300 and 500 watts (W). It might seem logical that the rating of the PSU determines the power draw of the computer, but this figure is actually the maximum power that can be delivered. Indeed, more often than not, most PCs will draw just a fraction of what the PSU is capable of delivering.

It’s possible to get a rough idea of a computer’s power draw by totting up all the components inside, but a far easier method is to purchase a power meter. These are relatively inexpensive and we are using one purchased from Maplin; the full retail price is £23, but it’s frequently on offer for £13.

Power meters such as this are very easy to use; most work by sitting between your PC’s plug (or any other electrical device’s plug) and the mains socket. To find out the power draw, press the Watt button and the screen will provide a real-time update of how much power is being drawn.

You can also measure how much power is drawn over a period of time in killowatt hours (kWh), which we will explain in more detail later. Once you have got the power meter hooked up to your computer, have a go at measuring the power draw when your computer is being used for different tasks.

The power draw will be at its peak when your computer is running processor-intensive tasks, such as 3D games and video editing. Measure the power when the computer is idle (for example just after it has completed starting up Windows) and it should be drawing far fewer watts.

You might also be interested to use the power meter when the PC is switched off; most desktop PCs will continue to draw between 1W and 5W. Similarly, spend a few moments finding out how much power other devices in your home draw.