Turn computer off or leave switched on?

derrick

Does anyone know the difference in cost of leaving the computer switched on overnight or turning off for what could be in excess of 12 hours per day.
I have been told by my computer supplier that leaving it on consumes the equivalent of a 100 watt bulb,this equates to 1k.w. over a 10 hour period,7 k.w. over seven days, @a rate of 7p per k.w. = 49p per week ,approx £26 per year, this would be better in my pocket than the power company, but does it cost as much to restart the computer daily as suggested by my computer supplier?
An energy "expert" on a radio station this week said no appliances should be left on standby,e.g. t.v. computer,due to the energy consumption,who is right? :-/

Thanks
Derrick

Tony_H_3

If you do not use your PC during the night & it could be turned off then you should. Whilst the PC is operating its expected life is reducing, to replace failed components which cost far more than any potential savings.

Most PC's have atleast a 200w power supply, with modern Multimedia PC's having 350w power suplies. IMHO a PC would cost more than a 100w light bulb unless you used power saving mode.

derrick

Hi Tony H
My computer has a 4 year warranty with the local company that supplied it, therefore they will replace components free of charge, and as I said above they recommend leaving it on, but do you know if it uses more power to boot it up each morning as against leaving it on all night,I am looking more towards my electric bill as against components.
If you are saying that my (3 month old ) computer is rated at least 200watts,then my above calculations at least double,therefore power usage wise it would be cost effective to turn off when not in use just like I would
turn off a 200 watt light in a room I am not using!

Tony_H_3

My advise is turn it off, without getting technical there was recently a thread about flourecent light & switching them on/off and the savings would only be achieved over a period of seconds. Bearing in mind it's your intention to turn off for excess of 8 hours the savings speak for themselves.

derrick

Thanks for the info (the PC is Windows XP)
So what my computer supplier said about using the same amount to boot up is a nonsense?
Do you know what the power consumption is to startup the computer?
Thanks

Tony_H_3

For the life of me I can't find the URL, but there is a website which Calculates the power used by your PC based on it's components. Hopefully someone will post with the URL. ;D

I couldn't provide specifics, but to boot a computer wouldnt use considerably more power / cost than to run it.

Toxteth_OGrady

Your computer is using about twice the power during its boot cycle as it does when at idle.

Since however the boot time is only a minute or so this is a minor overhead.

If your computer is left at idle for more than 2 minutes you will be using more power than a power off and then power on when you need to use it again.

You have to balance this against the inconvenience of not having it always on and immediately accessible and the reduced lifetime of hardware components such as drives and fans.

Best compromise is probably to power off overnight.

   8)

TOG

blinky

Your computer is using about twice the power during its boot cycle as it does when at idle.

Since however the boot time is only a minute or so this is a minor overhead.

If your computer is left at idle for more than 2 minutes you will be using more power than a power off and then power on when you need to use it again.

You have to balance this against the inconvenience of not having it always on and immediately accessible and the reduced lifetime of hardware components such as drives and fans.

Best compromise is probably to power off overnight.

8)

TOG

I agree - I tend to turn it off overnight but not if I'm only away for a short length of time. Cold boots put a tremendous strain on components, particularly the PSU and the voltage regulators on the motherboard. (bit like running your car from cold)

acupples

I would always turn my computers off at the wall overnight for a couple of reasons... some PCs still draw power while they are supposedly switched off. Probably not very much, but some will have leds that stay on, which annoys me, or will hum quietly (or loudly), even though they're meant to be turned off! Grr! They will also be warm to the touch sometimes. Also, plugtop transformers, which are connected to the same plug, always draw some power, and generate a fair bit of heat in some cases, so I turn the whole lot off if I'm not using them overnight. Hey, this is a money saving forum, just trying to claw back the pennies!
If you have a PC that doesn't draw power while it's switched off, then it probably doesn't need to be switched off at the wall.
Andrew

Odyssy

I think the recommendation to leave the computer on means to leave it on powersaving mode or hibernate when not using it for periods of more than three or four hours, based on the fact that the life of electronic components is shortened by the heating up and cooling down that occurs during switch off/on.
Certainly, one of my monitors (21" Iiyama) finally died last week after 11 years of daily use - 14 hours a day then powered down to standby overnight when it drew only 15w - enough to keep the components 'warm'. It was the tube that went not the peripheral electronics.

[Deleted User]

Your computer is using about twice the power during its boot cycle as it does when at idle.

As an electronics engineer I think this is nonsense. Where do you propose the extra power is going?

You'll save on the cost of electricity by switching off, but the cost of repairs is much more complicated.
In general the lifetime of electronic components is measured relative to the hours of use, but it's also related to the degree of stress they endure. This comes in a variety of forms, among which are surges in the power supply at the instant of switch on, and also thermal cycling as the equipment heats and cools alternately. One the whole, I'd recommend switching off if it's going to be for a long while, but don't switch on and off like a yo-yo.