OK... How much does electricity cost?

NeilF

NeilF

NeilF

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I'm trying to work out how much certain devices are actually costing.

If an item is using say 100W, how much does that cost say per hour?

Anyone know?



Just done a test here (at work) and my PC when off still uses 10W, and even more bizarre with my PC off, my LCD monitor uses 10W, on or off! Why on earth is the monitor using 10W with the power switch off! How bad/lazy design is that!
 
Have a look at your electricity bill but its usually around 8p per Kilowatt hour, so if your system drew 250w on average (just an example) then it would cost you 2p per hour.
 
So, 10W = about .08p/hr

So over the course of the year assume turned off on average 20hrs per day...

.08 * 20 * 365 = 584p

So my dual LCDs cost about £12 a year because the manufactures couldn't be bothered to put on a decent off switch :)
 
Most LCD screens dont have physical on/off switches, they are too 'uncool' I guess. Any kind of 'electronic' toggle switch, needs power to detect if the on switch is pressed again. Therefore the PSU is still active, to provide power to the detection circuits. A 10W draw is about average for standby power. Turning off the screen just disables the LED on the front, and prevents the screen autopowering if the PC is turned on.

If you dismantle a CRT based screen, they all have traditional 250V switches, which break the AC line. a lot of LCD panels dont even have integrated PSU's they take a DC feed, so there is no way to physically break the AC lines. If you really want to turn it off you'll have to switch of the mains at the socket.

If you want to design a more power efficient system, then you'll need a smartplug, its possible to buy 4way adaptors that detect how much power flow is going to the master device (your PC), and when you turn the PC off, it shuts off the AC power to all the slave sockets. AC power remains to the PC, so that standby power is still available.. even the PC's power switch is just an electronic sensor, so standby power is essential.

Perhaps we should all go back to the old IBM XT's... Anyone remember those huge high quality red flip switches used on old PC's :)
 
Corasik said:
Most LCD screens dont have physical on/off switches, they are too 'uncool' I guess. Any kind of 'electronic' toggle switch, needs power to detect if the on switch is pressed again. Therefore the PSU is still active, to provide power to the detection circuits. A 10W draw is about average for standby power. Turning off the screen just disables the LED on the front, and prevents the screen autopowering if the PC is turned on.

If you dismantle a CRT based screen, they all have traditional 250V switches, which break the AC line. a lot of LCD panels dont even have integrated PSU's they take a DC feed, so there is no way to physically break the AC lines. If you really want to turn it off you'll have to switch of the mains at the socket.

If you want to design a more power efficient system, then you'll need a smartplug, its possible to buy 4way adaptors that detect how much power flow is going to the master device (your PC), and when you turn the PC off, it shuts off the AC power to all the slave sockets. AC power remains to the PC, so that standby power is still available.. even the PC's power switch is just an electronic sensor, so standby power is essential.

Perhaps we should all go back to the old IBM XT's... Anyone remember those huge high quality red flip switches used on old PC's :)
Click to expand...
Great post ;) I think it should be put on a sticky somewhere along with 'xxxWatts PSU doesn't mean it will draw xxxWATTS!!!!!!!!' :rolleyes:
 
Corasik said:
so there is no way to physically break the AC lines. If you really want to turn it off you'll have to switch of the mains at the socket.
Click to expand...

Absolute madness isn't it! They put a power switch on that does NOTHING else in reality that turn off the power on/off led... Why on earth not actually break the mains circuit!

I intend going around my various house hold devices to see what they're power consumption is...

ps: Both my PCs at home are turned right off, along with all their devices (scanners, speakers, monitors). The only thing that's left on is the router...
 
Ive got 5 computers running 24/7 so according to the BBC my bill should be £125 on top of my normal electrical costs.

I dont know what my bill would be without the computers but maybe a fiver a week ? My bill is around £10 or just under. That leaves each computer adding a pound a week to the bill, hardly worth worrying about in my opinion.

TDF.
 
BBC said this in 2005. <price increases in elec since then.
Expect to see a LOT more on this given that the government has to decide between nuclear and fossil fuels <nuclear will win without a doubt.

I was watching one of the late night news debates last night, and it seems pretty obvious they are going to start educating people.
They actually said how daft the whole situation is when outside the BBC offices at midnight, nearly all the lights are left on in big buildings in London.

Just seems a pity that all the stuff my kids learn about green house etc etc at school, and they can't teach them how to turn a light off.

Sorry....had to have a dig about that ;)
 
TheDogFather said:
Ive got 5 computers running 24/7 so according to the BBC my bill should be £125 on top of my normal electrical costs.

I dont know what my bill would be without the computers but maybe a fiver a week ? My bill is around £10 or just under. That leaves each computer adding a pound a week to the bill, hardly worth worrying about in my opinion.

TDF.
Click to expand...

Sort of a shame in some ways really that the cost of electricy doesn't make it matter... if you know what I mean...

I'm not really advocating higher bills, but just more concern about general resource waste...
 
ihatelag said:
The BBC says if you leave your PC on 24 hours a day, it will cost you on average £25 per month.
Click to expand...

Must be those ******** Dell systems ...or a rip-off electricity supplier.

My X2 rig overclocked costs ~£10 per month. Draws ~260W full load (allowing for PSU efficiency).
 
TheDogFather said:
Ive got 5 computers running 24/7 so according to the BBC my bill should be £125 on top of my normal electrical costs.

I dont know what my bill would be without the computers but maybe a fiver a week ? My bill is around £10 or just under. That leaves each computer adding a pound a week to the bill, hardly worth worrying about in my opinion.

TDF.
Click to expand...

Doing the maths (on 8p per KWph), if your 5 systems (+monitors etc) draw about 400W...
8p * 400/1000 * 24 * 31 = £23.81 a month? = about £280 a year?

Got know idea how realistic 400W is though!?
 
I read this on another site that I can't post it here, and dunno just how reliable it is.
Regarding the efficiency of PSU's.

Seasonic S12-600

The S12-600 is also incredibly efficient, averaging 82 per cent at full load, which means it only requires 726W from the mains to produce 593W.

I picked that as it was the best performer, but you can see they use far more from the mains than they actually give. (also see post here on Q-TEC 650W that needs 725W from the mains to produce 498W)
So I suppose if people assume their CPU is drawing 100 watts, then it's taking a whole lot more from the mains.
The BBC have even quoted...

"If a million PC users switched to a more efficient power supply, it would save almost the equivalent of 250 thousand litres of gasoline a day."

I suppose the bigger picture here is buying a better PSU is going to cost you less to run it, but people aren't going to do that unless they can see it saving them money.
We know the large majority of users just go to that big PC shop in the UK and buy what seems cheap, but can you imagine how much their cheap PCs would go up if they all started fitting efficient (expensive) PSU's?

I dread the government getting involved with this (prolly happen one day) but maybe we will end up paying less for buying something more efficient.
 
I've got one of those things that monitor power usage on any electrical socket and have my surgemaster plugged into it.. And according to it i'm using 1187watts. Plugged into it is my pc, printer (which is off) router, pc speakers, 26" lcd tv, house phone base, and a ps2 on standby. If i turn off my pc speakers it drops about 120w and that's with the volume at 0 and nothing playing. The router uses about 80W, the tv 140w. Not sure of the rest can't be bothered to unplug and plug stuff in. I noticed even my dvd player uses 400w on standby!! same with the sky HD box just over 400w. but they're not plugged into this socket. My 42" Vierra uses a fair old whack of power with the panasonic surround speakers. all in all about 2.2kw when everythings on.. We tend to use between 15 and 25 a week in electric, which is not bad considering the houses central heating is electric!! And looking at my electric statement thingy it's 6.3p per KW/h off peak and 9.1p on peak.
 
u have to remember even though psu can supply upto its full rating it is not always doing this, do u leave all those systems on full load maxing out everything ? i dont think u use its full potential so then if u hooked a power meter to each would be the only way to see the true power draw from them. so yes u will use less than the theoretical max.
 
Corasik said:
If you want to design a more power efficient system, then you'll need a smartplug, its possible to buy 4way adaptors that detect how much power flow is going to the master device (your PC), and when you turn the PC off, it shuts off the AC power to all the slave sockets.
Click to expand...

Any brand names of this kind of thing I could look for? Wouldnt mind something that stopped the gentle leeching of power by devices im not using. I can think of at least the speakers and dell screen that work in this way, not much else I have on that does similar but even those would help. For the sake of a few quid to save me pennies in the long run it would be great, they REALLY should make more of this. Agreed on the lights etc in big office blocks tho - never do get the point to that, wouldnt really take much to have a master switch on all the lights. If REALLY needed a couple of strategically placed ones could be left but it certainly dont need them all.

Theres tonnes of mass wastage going on - it would take next to nothing (around £200) to make a diesel car run on veggie oil - they could make it for far cheaper than it takes to extract oil and job done - that would be 20 times our kyoto requirements done in 1 fell swoop. Accepted its not THAT simple in practise but even a 10% cut into normal diesel with engines that could take it would do kyoto - really dont understand things like this not being done.
 
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I think the government intends to meet the Kyoto Protocol by doing away with fossil fuel power stations.
It seems the one power station chucks out more filth that all the cars in the UK.

Then what do we do with the nuclear waste?
Double egded sword no matter what way you look at it.

Hmm this threads in danger of getting moved to the Speaker's Corner ;)
 
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