PC Power use on Stand-By

Rickycowslip

I rarely 'switch off' my PC, merely put it in 'Stand-By' as it will then switch back on instantly. People tell me this uses significant amounts of electricity, yet I'm not convinced. Surely if something is using electricity to any degree it will get warm, yet the fan is never activated when in Stand-By which suggests it is not heating up. Therefore the only electricity is that used to power the small LED light in the switch, and maybe a bit to restore the memory - an amount equivilent I would imagine to that of one's bedside digital clock.

Anyone know - how many pennies does it cost to leave a PC on stand-by over-night ?

calibrax

My company recently sent round a memo with this info, because they are trying to reduce the electricity bill for the office :


Hope this helps!

esuhl

To calculate the rough cost of running any appliance, you need to divide the power rating in Watts by 1000 (to get kilowatts - kW) and multiply by the number of hours (to get kWh). Your electricity company will tell you the price per kWh, so you can calculate the total cost.

For example, assuming a price of 6p per kWh, a 100W light bulb left on accidentally for two weeks while I'm on holiday would cost:

100W / 1000 = 0.1 kW
14days x 24 hours/day = 336 h

0.1 kW x 336 h = 33.6 kWh

6p x 33.6 kWh = 201.6 p

Rickycowslip

hmmm - interesting info, but I'm not sure it tells me the answer... using a machine all day and leaving on standby overnight will cost 76p as opposed to 83p if I switch it off ? So I'm making 7p a night by leaving on standby ? hurrah !

calibrax

Rickycowslip wrote:

hmmm - interesting info, but I'm not sure it tells me the answer... using a machine all day and leaving on standby overnight will cost 76p as opposed to 83p if I switch it off ? So I'm making 7p a night by leaving on standby ? hurrah !

No, you've misread it...

If you run a workstation and a monitor 24 hours a day, it costs 83p per day.

However, if you just put the monitor on standby overnight, it's 76p a day.

So you save 7p by putting the monitor on standby.

But better still, if you switch both off every night, then the cost works out at 28p per day.

Hope this clarifies things!

intel

All I know is thats its bad practice to leave stuff that does not need to be left on
like a PC as it could cost you your life via being a fire hazard...

A house up the road from be went up in flames because of dust in the
PC around the fan and the darn thing caught fire.

Rickycowslip

yeah but - that's my point... people 'think' it uses a lot of electricity to leave it on stand-by, but where does the electricity go ? Things using electricity get warm (just feel that lightbulb you've left on for the hour) however my PC left on stand-by overnight is as cool as a cucumber.

blinky

You could always use Hibernate - that way it will use virtually nothing as it dumps the contents of RAM to a file then shuts down. There is always a small amount of power used if it's not unplugged / switched from the mains. (That's why some boards have lights on to let you know there is power to the board).

£$&*"($£&(

You should always consider turning off not only as a money saving measure but an environment saving measure.

calibrax

Rickycowslip wrote:

yeah but - that's my point... people 'think' it uses a lot of electricity to leave it on stand-by, but where does the electricity go ? Things using electricity get warm (just feel that lightbulb you've left on for the hour) however my PC left on stand-by overnight is as cool as a cucumber.

A lightbulb uses 60w, and a PC on standby uses maybe 5w. So it would be quite a bit cooler. Also, the part of the PC that does warm up when it's on standby will be inside the power supply unit within the case, so you wouldn't notice much heat from outside.

If you have a laptop, the power supply (i.e. the part that converts mains electricity to direct current) is outside the computer... try leaving the power supply plugged into the mains, then feel the black box which is part of the mains lead... that will certainly feel warm to the touch.

andrewmoorcroft

My house has 2 work stations with 17" CRT screens on continually. The price in the table for this is £303.73 x 2 = £608ish. My electric bill is only £400 per year!!!
You also have to put a cost on your time wasted for powering up and waiting.
You also have to consider the effect of heating up and cooling down of the machine. Have you noticed that light bulbs often blow when you switch them on. A flickering bulb may last all day but switch it on and off and it will blow!
My company says leave it on unless it is a long shut down. Strangely more things fail on the 1st day back to work after a long holiday than any other time!
As pointed out earlier you also have to consider where the energy went. Of course most of it heats the house. In theory this reduces the heating required in the winter so reduces your heating bill. It is far more complicated than the table above suggests!