In this post I’ll explain in detail how much electricity an average computer uses and how much money you’re spending to use your computer.
A typical desktop computer (not including the monitor) uses about 65 watts give or take a few watts depending on the computer. A typical desktop computer with a processor running at a 100% load uses about 90 watts. The typical desktop in hibernation uses about 3-35 watts depending on the hardware.
A typical CRT (the big computer monitor) takes about 80 watts give or take a few. A typical LCD (small flat cool looking monitors) uses about 35 watts give or take a few.
Click here for my source to the above figures.
The formula to figure out much you’re spending each year on using your computer goes like this: A watts / 1,000 = B kilowatts * C hours per day of usage = D kWh * $0.13 (rate you pay from electricity company per kWh) = E (cost per day) * 365 = F (cost per year).
Click here for my source to the above formula.
I’ll do one for you.
I’m going to figure out how much it cost to run a computer that’s always at full load with the monitor off most of the time. I figure this computer uses about 100 watts 24 hours a day 7 days a week 365 days a year.
100 watts / 1,000 = .1 * 24 (hours per day) = 2.4 * .13 (cost per kWh) = $.31 (per day) * 365 = $112.32 (per year)
With all of this in mind here are a few quick figures:
Please note that these figures are done with the cost per kWh of $.13 This is as close to the average as I can get. Check your electric bill to see how much your being charged to get a better idea of what your computer is costing you to run.
Typical PC at a business:
Computer running 8 hours per day with 17″ CRT on for 8 hours per day = $56.94 per year.
Computer running 8 hours per day with 17″ LCD on for 8 hours per day = $39.86 per year.
*Computer running 24 hours per day with 17″ CRT on for 8 hours per day = $110.08 per year.
*Computer running 24 hours per day with 17″ LCD on for 8 hours per day = $93 per year.
*The computers above that run for 24 hours are set to not sleep when they are not in use.
Typical PC at home:
Computer running 4 hours per day with 17″ CRT on for 4 hours = $ 28.47 per year.
Computer running 4 hours per day with 17″ LCD on for 4 hours = $ 19.93 per year.
*Computer running 24 hours per day with 17″ CRT on for 4 hours per day = $ 94.90 per year.
*Computer running 24 hours per day with 17″ LCD on for 4 hours per day = $ 86.36 per year.
*The computers above that run for 24 hours are set to not sleep when they are not in use.
The figures shown above were calculated with a computer that uses 70 watts, CRT that uses 80 watts, a LCD that uses 35 watts, and an electric company that charges $.13 kWh which is as close as I can come to the national average. Check your bill to see what your being charged. A slight change in this number makes a big difference in the final numbers.
If you want to measure exactly how many watts your computer is using click here to purchase a kilowatt meter.
Click here to see my guide on how you can set your computer to use less electricity.
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