John Galea's Blog

My blog on Gadgets and the like

Cost of keeping a PC running 24×7

I like a number of technocrats have a number of PCs running in the house all the time. One is a media player but power management does not work right so I leave it on. So I was wondering, what is that costing me. So first off I had to go check what I pay for Hydro. So for me Between 11AM-5PM (6 hours a day) it is considered peak and costs 13.5 cents per KWH. Between 7AM and 11AM as well as 5PM to 7PM (6 hours) is considered mid peak and costs 11.2 cents per KWH. Lastly between 7PM and 7AM (12 hours) is considered off peak and costs 7.5 cents per hour.

So I discovered a few colleagues had watt meters. You plug the device you want to monitor into it and it can display the amount of power it draws and thus the cost of having it plugged in.

First off was a Killawatt. It displays lots of instantaneous information like volts, amps, watts, etc. But nothing other than that. While useful without some form of stat or the like you are relegated to staring at the display. And if the device you want to monitor cycles like a fridge etc then this is not a helpful solution.

Next up come the BluePlanet EM100. This device is much more useful. It has the ability to display max watt as well as KWH consumed. It also counts the time. So based on the two you can come up with an average power number. So a much more useful watt monitor. I did find when power consumption was super low the timer sometimes stopped counting.

First off I wanted to make sure the number coming out of this device was accurate so I plugged a 100W incandescent light into it and sure enough it read pretty close to 100W. And the two devices were also very close to each other, giving me that warm fuzzy that it was reasonably accurate.

My set side PC has a 650W supply. So before I had a monitor I guessed maybe it drew 300W which would come out to 71 cents per day, $5 per week, $21.73 a month or $260.83 a year. But what is the real number? Well idling it drew a shockingly low 65 watts. Watching a hidef movie being played back on it popped it up to only 70W. And on suspend the PC drew a minimal 10W. Wow. The PC by the way is a core i5 PC with two hard drives and integrated video. I measured about 6W of additional power adding a second hard drive!

So next up I thought I’d look at my Dell PowerEdge SC430 with 4 drives and an 8 core Xenon processor. Peaking around 286 watts during boot but settling down to around 190 watts average. This device runs 24×7 so this does cost a few bucks to keep running 😦 I would guess $165 a year.

If you have ever been close to an LCD display you can feel the heat coming off it. So I decided to see how much it drew. My 37″ Dynex LCD display draws about 140W. My 42″ LG Plasma display comes in at 150W peaking around 175W. So it draws more but not as much more as some had told me.

I have an older Gateway P4d PC which always seems to be warm, so I wondered how much it drew. It peaked around 160W and then settled down to 100W. So higher power than my set side PC but not as bad as my server.

As an interesting side note I have a wine fridge about the size of a normal refrigerator. I left the monitor on it for a day and measured .9 KWH consumed. So that would cost about $30 a year to run. Cheap and efficient!

Special thanks to Lance and Johannes for loaning me these!


May 27, 2014 - Posted by | Electronic gadget reviews, Uncategorized

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