You may be curious about how much your computer use adds to your electricity bill each year. This largely depends on what kind of computer you have and how you use it. Concentrating on heating and cooling issues in your home is more likely to save you money on your utility bills, but there are a few ways to make computing more energy efficient and reduce your monthly payments for electrical use.

# The amount of electricity a computer uses depends on the kind of computer. A desktop computer generally uses more electricity than a laptop, and Macs tend to use somewhat less electricity than PCs. How old or how new your processor is, and how fast your processor is, also will affect how much electricity a computer uses. Newer processors tend to be more energy efficient, but slower processors also use less energy than fast processors. For example, a desktop PC being utilized heavily may use 250 watts per hour, while a Mac laptop running less power-intensive tasks might use less than 100 watts per hour. To determine how much wattage a specific model of computer uses, you can check the sticker by the power supply, read the supplemental material that came with the computer, or contact the manufacturer.

# Another factor that influences energy consumption is what you're using the computer for. Surfing the web tends to hog more energy than typing up a document in a word processing program, for instance. Similarly, typing an email tends to use less energy than playing a graphics-intensive game online.

Time Frame
# How many hours per day you actively run the computer versus how many you turn it off or put it on standby also will affect how much energy it uses. In standby mode, a typical desktop computer may use less than 10 watts per hour as opposed to more than 200 watts per hour if it's engaged in heavy use.

# To conserve energy and reduce your electricity bills by a few dollars a month, you can choose more efficient components such as LCD monitors rather than CRTs. When you're planning a computer purchase, you can also look for an EnergyStar sticker. The EPA awards this designation to computers that use less energy compared to other computers of a similar type. Every additional piece of peripheral equipment you turn on-- such as speakers, printers, scanners and so on-- increases energy consumption, too, so it's best to leave them turned off unless you're actively using them. The best way to prevent the waste of energy, though, is to set your computer to automatically go on standby after it has been idle for a while-- typically 10 to 15 minutes.

# You may have heard the myth that it takes more energy to turn your computer off and on than to keep it running all day. This is not true for computers or for most other major appliances in your home. Modern computers usually take two or less minutes to boot up, so any time you will be away from your computer for 15 minutes or more, it makes sense to shut it down or have it go into standby mode.

Expert Insight
# Several websites have tables listing the typical amount of electricity used by various computer models. One example is the Approximate Desktop & Notebook Power Usage table published by Penn Computing, the information systems department of the University of Pennsylvania (see the link below in the Resources section). However, you must keep in mind that these are approximations. The best source of this information is the manufacturer. Even then, the manufacturer tends to report the maximum wattage from heavy use, and this may not represent how you typically use your computer.