How Much Electricity Does a Computer Use

How much electricity does a computer use? Enough that you should be concerned about it. Learn how to run your machine more efficiently.

Just how much electricity does a computer use? Enough that you should be concerned about it. Learn how to run your machine more efficiently.

Computer Wattage
A computer's wattage should be listed on the serial tag. You can check your computer to determine your computer's specifications; however, the listed amount is basically a rough estimate. Even during peak use, a computer may only use around 100 watts.

Generally, a desktop tower, not including the monitor, uses around 65 watts but can use up to 250 watts, depending on the hardware inside the system. Laptops pull about 45 watts, on average. Set your computer to slip into hibernation, and depending on what's inside your machine, three to 35 watts are used. Sleep or standby mode pulls one to six watts.

Monitor Rates
Consider the monitor use, also. A CRT monitor uses nearly 80 watts. LCD monitors use around 35 watts. Adding a screen saver does not affect the power; in fact, some elaborate screen savers can bump up the wattage. If you leave your computer on during the day but aren't always using it, set your monitor to sleep mode. Depending on the monitor brand, only up to 15 watts will be in use.

Total Cost
Want to know how your computer energy costs are each year? Follow this simple formula:

• Watts x Hours used a day divided by 1000. This gives the daily Kilowatt-hour (kWh) rate.
• Multiply that number by the number of days the appliance is used during the year.
• Multiply the Kilowatt-hour per year by the kWh rate from the local utility company. This determines the amount you pay to power your computer.

The next time your daughter falls asleep and leaves the computer running all night, you may not need to worry. Adjust computer settings for hibernation or standby and keep energy costs at a minimum.