As portable devices that sometimes need to operate solely on the juice of an internal battery, laptop computers are designed for energy efficiency. Newer laptops frequently make use of such innovations as solid-state hard disk drives without moving parts, energy-efficient LED screens and low-voltage processors to reduce their power footprints. Power demands vary with the make and model, but laptops generally draw far less electricity than comparably equipped desktop computers. (See References 1)
Many laptops operating at moderate activity levels use fewer than 60 watts of power, while desktop machines with LCD monitors use 60 to 194 watts, according to University of Pennsylvania data from February 2011 (see References 2). Tests on a range of computers run by CNET Labs in 2008 found laptops, on average, use only 25 watts when idle and about 60 watts while in use. Desktops use about 100 watts in an idle state and 145 watts when in use (see References 3).
The kind of laptop you have and what you do with it can affect whether the machine sips power or slurps it. Playing an animation-intensive game on a high-end gaming laptop with a powerful video graphics card can suck as much juice as simple word processing on a newer energy-efficient desktop. Cranking your display to maximum brightness uses more electricity than keeping it at lower brightness levels. (See References 3)
Save on electricity by turning the machine off when you do not expect to use it for a couple of hours. Even when you turn off a computer, it continues to draw power as long as it is plugged into an electrical outlet, so unplugging it is another way to shave your electric bill. If you want to avoid pulling the plug, connect the computer to a power strip with an off switch. (See References 4)
Laptops and desktops displaying the Energy Star symbol have met U.S. Environmental Protection Agency guidelines for energy efficiency. As of 2011, Energy Star displays use about 20 percent fewer watts than other computers. The "sleep" mode on an Energy Star computer uses 2 watts or less. The Energy Star program calculates U.S. consumers could save $700 million a year in electricity costs simply by putting their computers to sleep when not in use. (See References 5 and 6)
- CNET Reviews: Laptop Basics
- University of Pennsylvania; Approximate Desktop, Notebook and Netbook Power Usage; Feb. 15, 2011
- CNET News; At What Cost a Gaming PC? CNET Labs Tests PC Power Consumption; Matt Elliott; April 22, 2008
- U.S. Department of Energy; When to Turn Off Personal Computers; Feb. 9, 2011
- Energy Star: Displays
- Energy Star: Displays Key Product Criteria
A California-based writer, Mike Williams has written since 1975 on the environment, health care and wildlife for more than 70 media outlets, including the "Detroit Free Press", Agence France-Press and CBS. Williams holds a Bachelor of Arts in journalism from the University of Southern California.
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