Computer Energy Conservation
A typical desktop PC with a 20" flat panel LCD monitor requires about 100 watts – 80 for the computer and 20 for the monitor. Left on 24/7 for one year, the system will consume 874 kWh of electricity. That's enough to release 750 lbs. of carbon dioxide into the atmosphere – the equivalent of driving 820 miles in an average car.
To reduce power usage by as much as 75%, turn off your computer when you won't be using it for an extended period of time and enable power management features during shorter periods of inactivity.
As you can see from the chart below, the energy needed to power all computers on campus can really add up, but the total energy savings to the University can be significant if everyone will do their part to help cut energy usage.
| Yearly Average | |
|---|---|
| Minimal | 1580580 |
|
Partial (current) |
962203 |
| Complete | 388501 |
An Optimized computer is defined as being in use for 5 hours per day, on for 3 hours, and in standby for 16 hours.
- Minimal is based on none of the campus computers being fully optimized.
- Partial is based on an estimated percentage of currently optimized campus computers.
- Complete is based on all campus computers operating in an optimized manner.
Turn these off
The following equipment should be turned off (or, if possible, put in Standby Mode) at the end of the day and over weekends.
Monitors
Printers
Scanners
Powered Speakers
Please note that many devices, monitors in particular, continue to draw 9-16 watts of power even when turned off. To eliminate this draw, use a power strip that has the ability to switch off certain outlets and not others (or, alternatively, use two separate power strips) so that you can turn off any of the above without turning off devices that need to remain powered, such as your computer's CPU.
Computers
As a general rule, turn your computer off at night (or, if possible, put it in Sleep Mode) when you are not planning to use it. Although many computers back up data and update software and the operating system at night, most will attempt to update their security software upon startup. For example, the antivirus software licensed by the campus will attempt to update itself upon computer startup (on Windows) regardless of when it has been told to look for updates.
Screen savers and power-saving modes
Screen savers do not reduce the use of power by your computer; once your screen saver kicks in, your monitor will draw its full power load. All users, whether on desktops or laptops, should configure their computers to use the power-saving or energy star modes that shut down power to the monitor, hard drive, and computer itself after periods of inactivity. Putting your computer in sleep mode allows it to use substantially less power, allows it to respond to some types of network activity, and allows you to not power off the computer.
Won't turning my computer on and off every day damage it or decrease its usable lifetime?
No harm will come from shutting your computer down when it is not needed. Manufacturers report that turning a computer on and off will have no detrimental effects over the useful lifetime of the equipment.
What good will come from shutting your system down? Reduced energy consumption.
Doesn't my screen saver save energy?
A screen saver does nothing to reduce the energy consumption of your computer. (Modern monitors don't even benefit from the screen saver's original purpose – preventing image burn-in.) Enabling power management is the only means of consuming less energy when your computer is turned on but isn't being actively used.
Does my computer consume less energy when I’m not using it?
The difference in energy consumption between an idling computer and one that is being actively used is neglible. Properly configured power management settings are necessary to lower energy use in inactive computers.
When my computer goes to sleep, will I lose my network connection?
You will probably lose your connection to the campus VPN.
Will my computer still receive its updates if it is off when they try to run?
Although many computers back up data and update software and the operating system at night, most will attempt to update their security software upon startup. For example, the antivirus software licensed by the campus will attempt to update itself upon computer startup (on Windows) regardless of when it has been told to look for updates.
Can I use Remote Desktop software from home if my computer is in power-saving mode?
Remote Desktop will work if your monitor is turned off but not if your computer is off or in standby mode.
My office uses a group printer. Should I turn that off at night, too?
This should be a group decision based on considerations such as how often someone from the group may need to print at night, how long the printer takes to become ready to print, and how close the printer is to group members' offices.
Laptops
Although the initial purchase costs of laptops may be higher, they draw significantly smaller amounts of power in operation than desktop systems. These savings can be as high as 80-90% and should be factored into any purchasing decisions.
Printers
Networked printers can also serve entire workgroups and may also result in energy savings over individual printers.
Energy Star
Please note that the energy star tags found on computers are not a reliable guide to energy efficiency. They refer to the computer's support for power-saving modes and do not reflect the actual power usage of the system.
