Computer Energy Saving Tips

If you're wondering when you should turn off your computer for energy savings, here are some general guidelines to help you make that decision.

Computers use about the same amount of energy to startup as they use when they are on for about two seconds. For energy savings, consider turning off

  • the monitor, if you aren't going to use your computer for more than 20 minutes.
  • both the CPU and monitor, if you're not going to use your computer for more than 1 hour.

Make sure your computer is on a power strip/surge protector. When the computer is not in use for extended periods, turn it off with the switch on the power strip. Even when you turn some computers off with the switch on the computer itself, it still may consume a small amount of power. If you don't use a power strip, unplug the CPU and monitor.

Most computers reach the end of their "useful" life due to advances in technology long before the effects of being switched on and off ten or more times have a negative impact on their service life. The less time a computer is on, the longer it will "last." Computers also produce heat, so turning them off reduces building cooling loads.

For cost effectiveness, you also need to consider how much your time is worth. If it takes a long time to shut down the computer and then restart it later, the value of your time will probably be much greater than the value of the amount of electricity you will save by turning off the computer.

Power-Down or Sleep Mode Features

Many computers available today come with a power-down or sleep mode feature for the CPU and monitor. ENERGY STAR computers power down to a sleep mode that consume 15 Watts or less power, which is around 70% less electricity than a computer without power management features. ENERGY STAR monitors have the capability to power down into two successive "sleep" modes. In the first, the monitor energy consumption is less than or equal to 15 Watts, and in the second, power consumption reduces to 8 Watts, which is less than 10% of its operating power consumption.

Make sure you have the power-down feature set up on your computer through your operating system software. This has to be done by you, otherwise the computer will not power down. If your CPU and monitor do not have power-down features, and even if they do, follow the guideline below about turning the CPU and monitor off.

Note: Screen savers are not energy savers. Using a screen saver may in fact use more energy than not using one, and the power-down feature may not work if you have a screen saver activated. In fact, modern color monitors do not need screen savers at all.