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How Much Energy Does a PC Use Annually?

written by: Bruce Tyson•edited by: Linda Richter•updated: 2/21/2011

New environmental concerns and skyrocketing electricity costs have made it imperative to control energy use at home and on the job. Here we take a look at the average annual energy consumption of a personal computer to help readers with their efforts to analyze and budget for their power use.

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    Overview of PC Energy Consumption

    Computers and computer monitors typically represent the second-highest power consumption in office settings, so it is in the best interest, monitor, mrceviz of businesses of every size to find ways to reduce the average annual energy consumption of a personal computer.

    Online resources can help users calculate the average annual energy consumption of a personal computer. For example, the United States Government operates an Energy Star website that helps business and individual computer users estimate the average annual energy savings they can realize if they use certified computers and implement power management procedures.

    In the European Union, users can visit the EU Energy Star website (see references below). This site offers a calculator that helps compute annual power consumption and energy costs required to operate a computer. Users type in all their parameters, and the system displays estimated figures.

    Additionally, Energy Star websites have directories that help users find computers that are Energy-Star compliant.

    A 2006 study published by Dragon Systems provides general assumptions for computer power usage. They state that the average computer uses between 36 watts and 250 watts while in use and between 1 watt and 27 watts when idle. Even when turned off, the average PC will draw between 1.5 watts and 3 watts of power. The actual cost of operating a computer will vary based on the cost of electricity paid at a given location.

    Generally, newer computers should be expected to use power at the lower end of estimates, while older computers will normally use more power. Power consumption can also vary based on the amount of memory, the type of CPU, type and number of storage devices, and type of monitor they use.

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    Strategies for Reducing PC Power Consumption

    To reduce the average annual energy consumption of a personal computer, users can follow these and other simple steps.

    Replace CRT monitors with LCD monitors. Businesses with the older style CRT computer monitors can replace them with modern LCD-style monitors that consume less electricity and have more advanced power management features.

    Turn computers off. When computers are left on at the office all night and over weekends, they are on for about three-quarters of the entire week without being used. Companies concerned about the environment and their electric bill should consider instituting polices that require desktop PCs to be shut down at the end of every work day.

    Use laptops rather than desktop PCs. Because laptop computers are designed for power efficiency, using them rather than full-sized desktop models can be an effective approach to minimizing electricity used by PCs. Additionally, equipping employees with laptops can pave the way to mobile and remote workforces that can further reduce power use at the office.

    Automated power management. Computer profiles that define power management can be implemented on most computers. These settings reduce screen brightness, slow CPUs, turn off hard drives, and send a computer into sleep mode when idle. Implementing company-wide power management standards helps save power during the day while employees are away from their desks or doing paperwork.

    Buy new, Energy Star-certified computers. Technology has recently made great strides in reducing the power required to operate a computer. By replacing older models that lack the most recent advances, companies can significantly reduce their electricity consumption.

    By paying attention to the electricity used by computer resources, businesses can significantly reduce their operating costs while becoming environmentally responsible.

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    US Government at Computers for consumers, retrieved at

    European Commission Director General for Energy. Energy calculator, PC equipment, retrieved at

    Bray, Megan, Review of computer energy consumption and potential savings. Dragon Systems Software Limited, retrieved at

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