How much electricity cost to run a PC?

TG82

In the last couple of days, I've started using a PC in my home and I've realised according to the cost calculator we have in our home that it is costing around 7p per hour.

Now that is a great deal. If it's on 6-8 hours per day, that's an average of 50p per day, £15 per month.

Surely this cannot be right just for a PC?

I'm wondering whether there's a problem. Some of our electricity bills have been inexplicably high lately, but before I look into that, I wanted to know from anybody who knows whether this particular cost sounds right to them because to me it does not, and I've been shocked. Maybe I've only just awoken to the cost of utilities rather than just groaning at the bill, but still. Something seems not right to me.

macman

For it to cost 7p an hour, it would have to be using about 650w continuously.
That might be the max power rating of the PSU, but it's not going to be drawing anything like that all the time. I'm assuming that some of this time it will be in sleep mode unless you are actually using it 8 hours a day, in which case the consumption will be far lower.
A lot of older PC's only have a 3 or 400W PSU anyway-what is yours?
On what basis does your 'cost caculator' give this figure?

Premier_2

I would suggest you get yourself a plug in energy monitor and see for yourself what it actually uses.

Mine typically uses about 120W to 200W (but may peak slightly higher) - that excludes the speakers.

What did surprise me was that is consumes about 40W even when I thought it was off, not even in standby. That's equivilent to about 1 kWh per day (over £40 per year! :eek:) even if it's not used. Now it gets disconnected at the wall when not in use


Edit: to clarify, figures quoted are the sum of the base unit and monitor (but excludes speakers)

kjsmith7

My PC is quite old and uses 450w, my laptop uses a lot less.

espresso

kjsmith7 wrote: »

My PC is quite old and uses 450w, my laptop uses a lot less.

No it doesn't.

Cardew

kjsmith7 wrote: »

My PC is quite old and uses 450w, my laptop uses a lot less.

Older PCs used less than modern PCs.

As said above, it might have a 450w power supply but I doubt it uses more than 100W for the majority of the time

randm

Premier wrote: »

I would suggest you get yourself a plug in energy monitor and see for yourself what it actually uses.

Mine typically uses about 120W to 200W (but may peak slightly higher) - that excludes the speakers.

What did surprise me was that is consumes about 40W even when I thought it was off, not even in standby. That's equivilent to about 1 kWh per day (over £40 per year! :eek:) even if it's not used. Now it gets disconnected at the wall when not in use


Edit: to clarify, figures quoted are the sum of the base unit and monitor (but excludes speakers)

Are you saying that even if an appliance is completely turned off, even at the wall outlet, that if there is still a plug in then it will use electricity?or am i reading that wrong??

macman

randm wrote: »

Are you saying that even if an appliance is completely turned off, even at the wall outlet, that if there is still a plug in then it will use electricity?or am i reading that wrong??

No, he said it was switched off but still plugged in (and presumably still on at the wall socket). So the PSU was still live, which must account for the 40W usage.
Some PSU's have an on/off switch on the back, but not all.

Premier_2

macman wrote: »

No, he said it was switched off but still plugged in (and presumably still on at the wall socket). So the PSU was still live, which must account for the 40W usage.
Some PSU's have an on/off switch on the back, but not all.

That's right, it would still be plugged in and turned on at the wall socket, but the base unit would have been powered down (there's a switch on the front to turn it back on - it's a Dell) and the monitor (CRT) would also be switched off using the switch on the front (so not even in standby I thought, as standby light goes out when switched off).

But both units would still be consuming power - ca. 40W split roughly equally between them.

The speakers used about 10W more I think, even when not actually emitting any sound - but I rarely had them plugged in anyway (not used very often) and thought they'd be using some as they are powered by a transformer to allow 12V output

JasX

randm wrote: »

Are you saying that even if an appliance is completely turned off, even at the wall outlet, that if there is still a plug in then it will use electricity?or am i reading that wrong??

there will be various grades of "off", plugged in and just shutdown from windows will leave it drawing something as modern (last 5-7 years) ATX motherboards have an 'always on' rail so the motherboard can detect the power button being pushed.

if you have a separate switch on the back of the PSU that should be enough to properly cut power to it, and at the wall even better.

Mines got a 1300w PSU so really hope it's not using that all the time :eek:

-have recently discovered this which certainly seems to have quietened my PC down and should have helped cut its consumption but only certain motherboards will have features like this...

http://ewbandwidth.blogspot.com/2008/09/asus-epu-six-engine.html

marydot

When i have my pc on, i turn off everything else.I have a habit of having the Tv on in the bacground on mute,Ive stopped doing that now,if pc is on something else has to be turned off thats my rule. Im on a pre payed meter so I monitor it.