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How much does it costs to run a computer?

We have compared 4 PC and their consumption, to see how much money we spend on electricity. The proofs are quite simple and we only need a tester which can measure amperes in the alternate current. You can measure the electricity consumption of your own PC and draw a conclusion of your own. Although, you have to be very careful and prevent electric shock. The proof consists of measuring the amperes of alternate current which our PC consumes in four different situations. We won’t consider the potency factor.

1-Turned off but plugged in.
2-Turned on but without us working on it.
3-Turned on with a 50% charge.
4-Turned on with a full charge.

The scheme is the one you see on the illustration, and it consists of placing tester between one of the power cables and the socket.

The PC we are going to measure are the ones that appear in the below table. Each PC has its own configuration and we can’t compare the consumption in equal conditions.
However, this is not a deciding factor, since, for example, a Pentium III TV card consumes only 2,4 mA.

Processor	Pentium III (866 Mhz)	Pentium IV (1,7 Ghz)	Pentium IV (2,66 Ghz)	Core2 dúo (2x2,66 Ghz)
Motherboard	Msi MS-6309 V2	DFI NB72-SC	Asrock P4S61	Asrock 4core full-hd
Hard drive	Seagate 20 G.	Seagate 40 G.	Maxtor 80 G.	W.D. Raptor 74 G.
Graphics	Ati R128 (32M)	Nvidia Mx 440 (64M)	Integrada (64M)	Integrada (512M)
Power supply	Generic	Generic	Generic	Enermax Liberty 500W
Ram memory	384	384	512	2 Gigas
Ethernet	Realtek 10/100	Realtek 10/100	Realtek 10/100	Realtek 10/100/1000
Modem	Conexant	--	--	--
Rewrite CD	Lg	Sony	--	--
Rewrite DVD	--	--	Lg	Samsung
TV	Pinnacle Tv	--	--	--
Fan box	--	--	--	2x12cm

The measures we have obtained are the following:

Consumption	Pentium III (866)	Pent¡um 4 (1,7)	Pentium 4 (2,66)	Core2 dúo (2x2,66)
Plugged but not turned on	47,9 mA	46,1 mA	51,00 mA	61,6* mA
Turned on without charge	173,2 mA	175,8 mA	192,5 mA	364,2 mA
Turned on with a 50% charge	190,1 mA	197,1 mA	217,2 mA	440,6 mA
Turned on with a 100% charge.*	219,7 mA	225,4 mA	238,9 mA	551,5 mA

* The PC tower, of Core2 dual is a Tacens Tango Pro, which has a constantly empowered display, and from there we control the PC functions.

With these data, we apply simple electricity formulas to find out:

1-What is the power we are spending?
2-How much does this power cost us?

We know that the power in watts equals a power multiplied by consumption (P=Vx1). The power is measured in watts, the tension in volts and the current in amperes. Once we have obtained the power we calculate how much power we consume in a day, in a month and in a year. We multiply it by the price of KW. We have calculated it for the 4 measure situations: simply plugged in, resting, 50% charge and 100% charge.

For example:
Our Pentium III, only plugged in without turning it on, for a day, a month and a whole year would cost us:

P = V X I
P = 220 V x 0,0479 A
P = 10,538 watts / hour
A day: 10,538 x 24 = 252,912 watts / day.
A month: 252,912 x 30 = 7587,36 watts / month.
A year: 7587,36 x 12 = 91048,32 watts/ year.

The price of the Kw/h varies depending of the country and of the tariff, we approximately estimate it to be around 8,9868 euro cents (0,089868 euros) for Kw/h. The price would be:

A day: 0,252912 x 0,089868 = 0,0227 euros.
A month: 0,0227 x 30 = 0,681 euros.
A year: 0,681 x 12 = 8,172 euros.

1-We didn’t consider the potency factor.
2-Obviosly, these are simply guiding calculations of what power a PC might spend, and they depend of the cards, fans etc. (of what we have turned on and functioning).
3-It goes without saying that the monitor, which is also an important part of the final consumption of the “complete” PC was not considered.
4-We suppose that the electric power is between 220-230 volts. If you live in the country with other voltage electric current power, you will have to calculate the consumption based on your voltage and your price of Kw/h.
5-Obviously, we didn’t consider the PDV or other potential additions to the electricity price since it also depends of the household and the country you are in.

Table 1. Comparison of the expenses in euros, different PC-s in a day. Daily expenses in euros.

Daily	Pentium III (866)	Pent¡um 4 (1,7)	Pentium 4 (2,66)	Core2 dúo (2x2,66)
Plugged but not turned on	0,0227 €	0,0218 €	0,0241 €	0,0292 €
Turned on without charge	0,082 €	0,083 €	0,091 €	0,172 €
Turned on with a 50% charge	0,090 €	0,093 €	0,103 €	0,209 €
Turned on with a 100% charge	0,104 €	0,106 €	0,160	0,261 €

Table 2.Comparison of the expenses in euros, different PC-s in a month. Monthly expenses in euros.

Monthly	Pentium III (866)	Pent¡um 4 (1,7)	Pentium 4 (2,66)	Core2 dúo (2x2,66)
Plugged but not turned on	0,681 €	0,654 €	0,723 €	0,876 €
Turned on without charge	2,46 €	2,49 €	2,73 €	5,16 €
Turned on with a 50% charge	2,70 €	2,79 €	3,09 €	6,27 €
Turned on with a 100% charge	3,12 €	3,18 €	4,8 €	7,83 €

Table 3. Comparison of the expenses in euros, different PC-s in a year. Yearly expenses in euros.

Yearly	Pentium III (866)	Pent¡um 4 (1,7)	Pentium 4 (2,66)	Core2 dúo (2x2,66)
Plugged but not turned on	8,172 €	7,848 €	8,676 €	10,52 €
Turned on without charge	29,52 €	29,88 €	32,76 €	61,92 €
Turned on with a 50% charge	32,40 €	33,48 €	37,08 €	75,24 €
Turned on with a 100% charge	37,44 €	38,16 €	57,6 €	93,96 €

Is it a lot, or not, to pay 10.52 euros a year for a PC while merely having it plugged in?.
I think it is, but then we can unplug the power cable from the socket every day (what we don’t usually do), if not, we pay the bill and that’s it.
And 61,92 euros to have it functioning? Definitely yes, it is a lot.
Apart from the fact that turning off the computer when we are not using it saves us some money; it’s also much more “ecological” to do so.
Especially now with all the climate changes and what now. We advise you to turn it off when you are not using it.