Tech

Save electricity on PCs, notebooks and monitors

Energy prices will explode in winter 2021/2022. A good time to optimize the energy requirements in your own four walls and thus reduce costs. Our series of articles with the focus on saving energy costs shows how and with what this works. This article originally appeared in mid-2020 but is still valid today.

Well-configured desktop PCs are not power guzzlers, mini PCs swallow less than some LED lights. Notebooks have to work even more economically because they can even feed their displays from the scarce battery power. But even frugal devices can be set up incorrectly or used clumsily, so that they waste electricity senselessly. And even if each individual (charging) device only consumes 1 watt, the standby power consumption of several devices adds up. It is therefore worthwhile to take a critical look at the domestic IT landscape.

The simplest tip was already explained in the article “Reduce power consumption in the household and save money”: Switch off frequently. This does not mean automatically shutting down the PC after 10 minutes of inactivity, but at the latest after 30 minutes or an hour. This can be easily set under Windows 10 via the “Settings for network operation and energy saving” or the “Energy saving plan”.




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Energy prices will explode in winter 2021/2022. A good time to optimize the energy requirements in your own four walls and thus reduce costs. Our series of articles with the focus on saving energy costs shows how and with what this works.

If you click around there anyway, you can also check the dead time until the monitor is switched off: 10 minutes is a typical value. Modern flat screens with LED backlight can withstand frequent switching off without any problems and light up with full brightness immediately after switching on again.


A reasonable period of time before the computer and monitor go into standby helps to save electricity and does not cost any convenience.

A reasonable period of time before the computer and monitor go into standby helps to save electricity and does not cost any convenience.

A reasonable period of time before the computer and monitor go into standby helps to save electricity and does not cost any convenience.

When you no longer need the PC in the evening, a switchable socket strip helps to conveniently disconnect all peripheral devices from the power supply. However, you have to shut down the PC first before you manually switch off the socket – if a computer is suddenly switched off, there is a risk of data loss. Automatic master-slave sockets need a little electricity themselves, but they work more comfortably: They use a current sensor to detect when the master device switches to standby mode and then switch off the other sockets.

But you should think carefully about which devices you plug in there. The monitor and power supply units for external USB disks, USB hubs and active speakers are not critical. Inkjet printers, on the other hand, do not like it if the juice is turned off before they have moved their print heads into a park position in which they are protected from drying out. A network printer and central network storage device (NAS) that other users should also use do not belong on the power strip, which switches off automatically, as well as the WLAN router – otherwise the home network will be paralyzed.

In the past, the tip was often read to disconnect all chargers and plug-in power supplies from the mains when not in use. In principle, this is still smart because it also reduces the risk of damage from overvoltages (lightning strikes in the vicinity) and fires. But it is also uncomfortable and does not bring about any significant cost reduction in modern chargers that only consume fractions of watts without a load.


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More from c't magazine


More from c't magazine

More from c't magazine

However, there are also old, inefficient power supplies and unimaginably poorly made peripheral devices: Some older USB hard drives in 3.5-inch format swallow up over 10 watts even in standby – twice as much as a good mini PC in operation. Rule of thumb: If a power supply unit heats up when the device being supplied is not in use, or if a fan rotates inside, it draws a significant amount of electricity. Then you should disconnect it from the power supply as often as possible, if necessary by pulling the plug.

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