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Conserving Energy with Your Computer

Delphineous SilverwingGood Ol' Geek
In today's world it is necessary to be Green - that is to save energy and reduce your impact on the environment. You can save electricity automatically, by taking advantage of a few simple features on your computer. Modern computers include power saving features like standby and hibernation modes, plus the ability to turn off components when not in use.

Device Conservation

Laptops and other portable computers for many years have been able to shut off their built-in LCD monitor and Hard Drives, allowing them to conserve energy while running on battery. Now, most modern desktops (and servers) have this capability too, along with other energy cutting measures. By automatically shutting off the hard drive and monitor or reducing processor power when not in use, the energy consumption is reduced to a fraction.

Many computer manufacturers will have a best power saver mode enabled when the system is built. If you decide to tweak the settings, be careful not to set your times too short. Using short intervals for device power off settings may result in shortening the life of the device, simply due to the device powering off only moments before you need it on again. Imagine going to bed and having someone wake you every 10-15 minutes to tell you something.

Recommendation (Plugged In)
Let your screen saver do it's job and begin running after 12-15 minutes of user inactivity. 10 minutes is typically too short, some of us need that much time to thoroughly read a page on screen or answer the phone.

Your screen saver is running and you aren't using your computer at the moment. Setting your display power off around 20-30 minutes is quite reasonable without being excessive.

Your monitor has been off for quite a while; it's time to power off your hard drive. Timing here is a bit sensitive and dependent on system performance. 30-45 minutes may work well for you. If your work break is usually 30 minutes, then 45 minutes will work best to prevent drive shutdown just before you get right back on the computer. If your break is an hour, then 30 minutes might do the trick.

Recommendation (On Battery)
Forego the screen saver and power off the LCD panel with about 15 minutes of inactivity and power off the hard drive after 20 minutes of inactivity.

Laser printers, and some other types, have a power saver or standby mode to save energy. Often laser printers lower the temperature of the fusing unit and slow down fans to conserve electricity when in standby mode.

Modern laser printers are more energy efficient than older printers, however utilizing their power saver mode will improve energy usage. Whether your printer is new or old, if you infrequently use your printer, set your power saver/standby mode to a low number like 30-60 minutes.

Inkjet and impact printers do not usually offer power saver modes, because their components do not require much electricity when not in use. In these cases, simply turn off the printer when you do not plan to use it for extended periods.

Standby Mode

Most computers built in the last several years, when coupled with a modern operating system, feature a Standby mode (also called suspend or sleep) that turns off a computer’s hard drive and monitor and reduces the motherboard’s power consumption to the absolute minimum required to retain the memory contents. Resumption of the computer is usually very quick, mere seconds, and leaves the computer programs in memory just as before system standby.

Recommendation (Plugged In)
Set your computer to automatically suspend when not in use for 45-120 minutes - this recommendation is a large range, because the timing greatly depends on your normal operating behaviors.

Some computers feature a standby or sleep button on the computer case or keyboard - often with a crescent moon icon. You don't have to wait for your computer to automatically save electricity; if you know you will be away from your computer for an extended period, simply put it to sleep yourself.

Whenever stepping away from your computer, remember to save your work. You don't want to lose any information if something goes wrong while you are away.

Standby/Suspend mode is not recommended for servers. Regular network requests will not bring the system back online to provide data to client computers. Specially formulated network requests may be able to bring the server back online, however this is impractical

Recommendation (On Battery)
Set automatic standby/sleep to around 30 minutes of inactivity.

Remember - when in standby/sleep mode, your computer is still powered on, but using much less electricity. Any computer left on or in a suspended mode should not be put in an enclosed case. Because the system is still powered on, it is still generating heat and needs to be able to self-ventilate.


Hibernation mode is useful for returning your computer to the last operating state, while conserving the same electricity as if the computer was turned off. One drawback of hibernation is that the start-up time from hibernation mode is just about as long, and sometimes longer, as turning the computer on after a normal shutdown. The more memory your computer has the longer hibernation and resumption will take.

When a computer hibernates it copies all of the contents of memory to a file on your hard drive and then turns off.  If you have 6 GB of memory, then you will have a hibernation file on your hard drive about 6 GB in size. When you turn your computer back on, the hibernation file is copied from your hard drive and used to rebuild the memory contents to how the computer was before hibernation.

Recommendation (Plugged In)
Use hibernation mode only when necessary. If you don't need to hibernate, just save your data and shutdown your computer. This allows it to "refresh" on the next power-up.

Hibernation is not recommended for servers, just as mentioned above. A server simply cannot provide information to client computers while it is down.

Recommendation (On Battery)
A laptop or otherwise portable computer using battery power could be set to automatically hibernate after 40-60 minutes of inactivity or when there is 10% remaining of the battery life.

When defining your hibernation setting, keep in mind the typical battery life for your device. If your battery usually lasts two hours, then you would want to set the time period shorter than if you usually get four hours from your battery.

As already mentioned, before you step away from your computer, remember to save your work. You don't want to lose any information if your battery dies while you are away.

Turn It Off

It may seem simplistic, but it is effective. If you are not using your computer, shut it off. There are limitations to this, of course. If you are stepping away from your computer for an hour or so, it may be more damaging to your computer to turn it on and off, over and over, each day than it would be to leave it on the whole time - especially when considering modern power saving features.

Recommendation (Plugged In and On Battery)
Turn off your computer over-night and while you are away from it for more than a few hours.

As an added bonus, any devices powering down automatically when not in use may help to extend the life of the component, simply by not being powered and running non-stop. This is particularly true with devices with heating elements and constantly moving parts like laser printers and hard drives.

Unfortunately, I cannot guarantee your results. Computer systems vary from model to model and your normal use of them will impact "best practices" for your environment.  The recommendations provided herein are based on my experience with technology over the last 30+ years. Your needs may require additional adjustments, but the information provided is a great starting point.
Delphineous SilverwingGood Ol' Geek

Comments (1)

thanks, useful infos

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