Get this (easy) or this and then plug wattage into this. My mb uses about 240 watts @ 3.6G.  So @ 9.3 cents per kw/h that's 54 cents a day if I leave it on 7x24 at this OC.  Speedstep, sleep, etc will reduce electrical cost.  Don't forget to add taxes and other charges they tack on to the electric bill to determine your real cost per kw/h.

Damn, I thought it cost a lot less to run this damn thing:

Cost Per Hour: $0.037600
Cost Per Day: $0.902400
Cost Per Week: $6.317
Cost Per Month: $25.27
Cost Per Year: $328.47

Avg about 330w(idle) - 720w with everyday gaming so I just tossed about 400w into the mix. Use my UPS battery to monitor use. Cool Usage calc!

interesting thread. used to share a house with about 4 other people (rent/utilities) and one guy was always yelling at me and my bro to turn off our PCs during the day to save on electricity. it seems he really had nothing to complain about afterall.

That's a reasonable average.  Take into account too, that it's not just your PC that consumes the electricity, but also your monitor, speakers, cable modem, router, printer, external hard drive and so on.  To get the true cost of running your PC, you would also have to include those devices as well.   The cost at that point may nearly double.  Ovens, clothes dryers, furnaces, air conditioners and some big screen tvs use WAY more juice than a PC.  Although, unplugging or just turning off certain devices when not being used may not save much individually, but when combined it would certainly add up over time.  Want to offset the electricity your PC uses?  Take a few days a year when the weather is nice and open some windows in your home instead of turning on the A/C.  Those savings will add up quick.

Okay, before when I was running my computer 24/7 I was paying $112 a month.  After turning my computer off every night and while at work my bill dropped to $101 a month.  $11 a month is $132 a year or by my math 3-6 game purchases a year.  Seems more than worth it to turn it off during the day while at work and night after I'm done with it :)

Also consider the possible costs to remove the heat generated by the PC.  If your PC consumes 300 watts of power, that's 300 watts of heat generated.  Depending on the way you cool your home/office, it could cost more to remove the heat then it did to generate it.

You are assuming we all pay to "cool" our homes , i'm in Canada we need the Heat  

Hillguy: you hoser ;-)  Why is your house underground?  I tried to visit Canada once, but it was closed.

I make a good living, but one of the things I have always found to be true is when you want to save money, it is the recurring stuff you pay for each month--those things, cumulativlely, all added up, are the difference between saving money and not. 

In my house, I noticed a $20 drop per month in my electric bill when I turned off (set auto sleep after 30 minutes) just the office computer (it was on 24/7).  I have four computers in the house - easy money.

That is true - the amounts are fairly minor per device, but add them all up.... 

Obviously not in the same class of a savings as turning off or sleeping device.

Where I live, the final-cost-to-me electrity is $1 per year, per watt, if I run it 8hr/day.  So a 300W system would cost me $300 a year as long as I don't use more than 8hrs each day.  I'll use my rate for the folling examples.

I have a link in my sig that details CPU lifespan as a function of wattage ratios, but I'll save you the trouble and copy/paste:

A simple formula for estimating the ratio of power due to an OC is (the Bclock ratio) x (multiplier ratio) x (CPU Vcore ratio)², ratios with respect to stock values (which is batch dependant).

How is this relevant?  4Ghz is 50% faster than 2.66GHz, which is approximately double the wattage (both heat and power) depending on the batch and individual CPU properties (no two 920's are alike).  For an i7 920, that's 200W for the CPU at 4Ghz, about as much as a high-end video card like GTX285 or GTX470.  It means adding $100/yr to your electric bill for the CPU alone.

Many people who overclock justify the extra costs, as the whole reason they do it is for what they use the system for.

If you don't know how many watts your PC uses and are too cheap ;-) too get the watt meter, you can estimate your power usage here  I tried it and it was ~ 20 watts over my actual.

mcochris
Get this: my i3 530 HTPC (MSI) @ 133x22 (2926 Mhz) uses 25 watts idle and 68 watts at 100% load!  At 189x19 (3591 Mhz), 54 watts idle, 78 watts load.  Integrated graphics.  So I gotta be asking myself: punk, is the i7 920 worth 3x the power?

Of course it is, and then some!

as long as i am in college and dont pay for the electricity, i will fold and leave it on all the time, once i start paying, i may change my mind

HalloweenWeed
Lets take a computer that actually uses 525 watts.

Pulling 525W at idle would be very high.  I have a kill-a-watt and my UPS tells has an LED display showing how much is being pulled from the wall.  I have an OC i7 920, 2x 285s, 3 hard drives, 7 fans, DVD-RW, etc.  and when my computer is sitting idle with the monitor off I am pulling around 220W from the wall.  Doing stuff like web browsing I pull around 330W.  When I am doing intense gaming it varies widely, but can get a bit over 800W. 

The way I calculate cost is by using the approximation $1 / watt / year.  This works out to 11.4 cents/KWh, so specific cost can be off by a bit; but this approximation is easy to do and gets you in the right ballpark.

I leave my computer on all the time, and use it for gaming maybe 20 hours a week.  20 hours a week  is about 12% of the time, so my cost is like 700W * $1/W/Yr * 0.12 + 220W * $1/W/Y * 0.88 = ~$280/yr.  If I turned my computer off when I was not using it, say maybe 75% of the time, then I could save 220W * $1/W/yr * 3/4 = $165/yr which is a non-trivial amount of money.

HVAC cost is an interesting angle.  In the winter when I am running the heat then this power is really a wash, because if my computer did not heat up the house then my furnace would have to fill in this extra heat.  In the summer when I run the AC though, I get billed double (a little more than double actually): for the computer power and for the AC to remove that heat.  So it is like a 0x cost multiplier in the winter, 2.3x multiplier in the summer, and 1x in the spring and fall.  What I need is a way to vent the computer heat outside during the summer to get that multiplier back down to 1x :)