Electricity, that is.

Yesterday I picked up a Kill-A-Watt, which I had intended to do for a while.  I also got a DVD burner, compressed air and CD sleeves, but those were more like impulse buys.  Anyway, I had a lot of fun last night (when I probably should have been cleaning up for tonight's party, or sleeping) plugging things into it and seeing what their power draw was.  As expected, my computer is a huge power-sucking beast: the system unit alone draws 250 watts at rest (close to 300 when powering up, or running dnetc or 3DMark).  Throw in my 21" CRT and scanner and you're looking at an idle power usage of about 370 watts, or close to 500VA (I'm not an elec, so I don't know the difference between "active power", or watts, and "apparent power", or VrmsXArms, so somebody needs to take me to school on that).

Compared with measurements taken at the office of a few of my test machines (a single-CPU P4 box with onboard graphics ran at 75W, while my awesome dual-Xeon w/nVidia Quadro ran at 135W), this is terrible.  I have definately been doing the right thing by getting into the habit of turning my computer off when I'm asleep or at work.  (The Tyan Tiger MP's ACPI doesn't work very well, putting the computer into "standby" only seems to turn off the hard drives...the fans keep running, so I assume it's still essentially on).

The meter also has a cummulative counter/timer so you can see the total kWH used over time, so you can get a nice idea of the cost of running things in, say, a month.

Now, what exactly does this mean?  Looking at my last power bill, I'm basically paying about $0.20 for a kWH.  So, in the worst case, with the computer powered on all the time, doing useful work, I'd use about 8 kWH/day, meaning 240 kWH/month, or $48/mo.  Not horrible, but not insignificant as many people assume.

There's a double whammy, actually, because all that energy is mostly dissipated as heat, which means that the A/C works harder when it's in use (which is 3/4th of the year around here).

But here's the real kicker. Thanks, no doubt, to some godless Yankee bleeding-heart lib'rul congresscritter, the first 250 kWH in a month costs about $7, and after that they gouge the hell out of you.  If I was an accountant at Enron, I could say that the computer used the first 250 kWH of the month, and that my ongoing operating costs were essentially zero!  However, being a gloom-and-doom Chicken Little type, I choose to say that my computer is eating all that essentially free power, which could be going to my fridge or A/C (the other two big ones).

So, I'm starting to research building a Core 2 Duo-based machine, with the goal of having an idle running power of <100W.  That should certainly be possible if I'm willing to forego the possibility of gaming on the system and use on-board video only.  I'd still want to turn it off when I wasn't at home, but it would mean those days when I worked from home or spent all day on the computer wouldn't be so wasteful.  It would also, hopefully, mean the end of it sounding like a 747 on takeoff roll whenever I fire the thing up.  Totally fanless would be preferable, but I'll settle for one variable-speed 120mm in the back.

Other interesting household power draw observations:

• Entertainment center (minus hi-fi audio, which is still on the blink): 60W.
• Box fan: 75-130W.

I will eventually get tired of monitoring how much my computer sucks down and will look to see if my fridge is 120V, in which case I'll do some long-term monitoring on it.  It was brand new when I moved in to the place almost three years ago so it shouldn't be that bad.  I should probably clean back there anyway.

I would love to see the pro version of this thing which could use some kind of IP-over-power technology to send readings back to a central monitor, so I could get my entire house rigged up like that and always know exactly how much I was killing the planet.