How much energy does a computer use?

Nowadays, computers are a fact of life, whether we like it or not. We use them every day for work, leisure, business and more.

All the information and entertainment you want is one click away. No wonder that we seem to hardly ever switch our computers anymore. But have you ever wondered how much energy does a computer use?

A desktop computer which is never switched off (only put in sleep mode) uses up to 4 times as much energy per year as a mid-size refrigerator, that is about 1,750 kWh! A gaming computer with a strong graphic card and a number of peripherals connected used 5 - 8 hours daily is going to consume a similar amount of energy.

These were some extreme examples but what about average energy use per hour?

Desktop computer	60 - 250 W
Laptop	14 - 45 W
Standby mode	2 - 2.8 W
Sleep mode	ca. 4 W
Printer	ca. 5 W
Loudspeakers	ca. 20 W
Modem	ca. 10 W
27-inch LCD monitor	ca. 25 W
17-inch old type CRT monitor	ca. 80 W

As you can see, energy use depends on the type of computer, the number of peripherals and on whether you remember to unplug your devices after use; standby power consumption is sometimes called ‘vampire draw’ and for a good reason!

Typical annual energy use ranges from 30 kWh (rarely used laptop) to 1000 kWh for a frequently used desktop computer.

Did you know?

Files such as music, photos, documents etc. need energy to be stored on your hard drive. Strictly speaking, recovering the files from he computer’s memory requires the more energy, the more fragmented the old files get over time. That’s one reason why it’s a good idea to clean your hard drive from time to time.

Have you got any other tips to reduce a computer’s energy consumption?