Sunday, April 20, 2014

Calculate your PC's energy use

Microsoft's free Joulemeter utility gives you a rough estimate of a Windows system's power consumption. Plus: tips for reducing your electronics energy bill.



According to Michael Bluejay, who also goes by Mr. Electricity, it costs from $631 to $5.50 per year to power a PC.
Even Mr. Electricity admits that's quite a range. A more typical annual energy bill for a Windows desktop PC that uses an LCD monitor and has sleep mode enabled is less than $10.
Microsoft's free Joulemeter program lets you calculate the power used by a Windows desktop or laptop. Joulemeter's developers intend the program to be used in conjunction with an external power meter when measuring a desktop's energy consumption, although the program's Manual Entry option generates an approximate power-usage number; the energy use of laptops is determined without requiring an external power meter.
For precise calculations of desktop power consumption, the Joulemeter user guide indicates that a WattsUp Pro power meter is required. WattsUp meters cost from $96 to $196 on the vendor's site.
The program also estimates the amount of energy being used by each application currently running. Enter the name of the program's executable file (such as "firefox.exe") in the text box under Application Power on the Power Usage tab and click the Start button. You can also save the current readings to a file for future reference.



When I used Joulemeter's manual approach to estimate the energy consumed by two Windows 7 desktops and a Windows 8.1 laptop, the utility indicated that the desktops used about 75 watts an hour and the notebook about 25 watts an hour. Since our local power company charges an average of just more than 15 cents per kilowatt hour, our household's computer energy bill is in the vicinity of $1 a month.

Of course, this figure doesn't include the cost of powering our two iPhones and three tablets. In September 2012, Outlier's Barry Fischer calculated the cost of charging an iPhone 5 and a Galaxy S3 for one year at 41 cents and 53 cents, respectively. In a post from June 2012, Don Reisinger reported that an iPad's annual energy bill comes to $1.36, according to a study conducted by the Electric Power Research Institute.

No matter how you slice it, that's a lot less juice consumed by our gadgets and computers than is used by other household appliances. According to Mr. Electricity's TV energy use calculator, a 46-inch Samsung LCD TV that is watched an average of 5 hours a day runs up an annual energy tab of just under $47. That's the equivalent of 537 pounds of CO2 pumped into the atmosphere, according to the calculator's figures.

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