Maths question

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Naon
Posts: 183
Joined: Mon Sep 25, 2006 1:00 am

Maths question

Post by Naon »

How do you work out how much it costs in electricity to run your computer 24/7 please .. ?
UBT - Timbo
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Post by UBT - Timbo »

Hi Naon,

The simplest way is to get hold of a device that plugs into your wall socket and which you then plug your PC into that.

Maplin do a device like this:

http://www.maplin.co.uk/p/15a-plug-in-e ... itor-l61aq

I got one of these and it's been very useful.

They also do something a bit more flash, like this:

http://www.maplin.co.uk/p/edimax-smart- ... ring-a00ta

This then gives you an absolute readout of the amount of power you are using via the specific socket.

Then, it's just a question of finding out what tariff you are on, for your leccy bills and dividing one by the other.

So, if you are using (say) 500 Watts (or 0.5 kW) and you're being charged say 12p / kWh, so the PC will cost you 6p per hour it's on and working.

Once you have the cost per hour, then just multiply by 24 to get the cost per day.

regards
Tim
Woodles
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Location: Cambridgeshire

Post by Woodles »

Work out (or measure) the amount of power it uses normally in kilowatts (1,000 watts =1 kilowatt)

Divide by PSU efficiency if working out from component specs.

Multiply by 24.

Multiply by the cost per unit of your electricity supplier.

ie. 500 watts normal use according to the PC spec.
/0.8 (80% efficient PSU) = 625 watts
*24 = 15 kilowatt hours a day.
*0.16 = £2.40 a day.

Or leave it off for a day, read the meter over 24 hours, switch it on for a day, read the meter to see the extra power used, multiply by the price per unit (not as accurate unless normal power usage is very constant)

Mark
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