How Much Does Your Computer Suck? Quiescent looking PCs are actually
wasting serious amounts of electricity.
By: John Shepler
Your computer sucks. They all do. It's not a put-down of style
or technology. Just an energy statement. What every computer
sucks is power. Some pull electrons out of the line so fast they
nearly melt. But they all suck at least some electricity and
likely more than you might think.
Why do we care? Because of this simple equation: Power = Money
Electricity is not free and not likely
to be anytime soon. In fact, in many areas the price of electricity
is rising. Commonwealth Edison in Illinois just raised our rates
a purported 24% for consumers. But that's an average bill that
includes both the cost of the electricity and the cost of transmission.
The transmission cost isn't changing. It's the energy cost that's
coming off a rate freeze of 10 years. If you use more than the
average amount of electricity, your bill will go up faster. If
you can find ways to draw fewer kilowatt hours each month, you'll
keep your costs at bay.
I'll have to admit I've been pretty casual about leaving my
computer running for most of the day. Since it's used for business,
I'm on it a lot writing blog posts, creating web pages, doing
research and answering email. But these activities are spread
out over about 12 hours every day. Not that I'm pounding the
keys all that time. Actually, I'm in and out of the office a
lot. I like to leave pages open on the screen and have them immediately
ready when I sit back down. Does this sound like your office
sticker shock of this month's electric bill got me wondering
if I'm wasting a lot of both power and money or if it's so insignificant
it's not worth worrying about. To find out, I bought a cool little
monitor called the "Kill A Watt, Electricity Usage Monitor"
built by P3 International. It's a handheld meter that plugs into
an outlet between the device you want to measure and the wall
power. There is a LCD screen and 5 pushbuttons on the front that
will tell you line voltage, amps draw, watts and VA power, line
frequency, power factor and kilowatt hours. Specified accuracy
is 0.2%. Best part is that it costs just under $30.
I used the Kill A Watt to satisfy my curiosity about the power
usage of my PC and monitor and had the eye opening results in
less than an hour, including some calculations on cost. The machine
I'm using is a fairly garden variety Compaq Presario 6000 series
running at 1.6 GHz with 480 MB of RAM and and an 80 GB hard drive.
The Monitor is a ViewSonic VX900 19" flat panel display.
Now here are the measurements I got using the Kill A Watt
P3 power monitor. The PC pulls 1 watt even when turned off. That
jumps to 89 watts when it is on and 109 watts during disk accesses.
The power goes down to 3 watts when the PC is in standby. The
monitor draws 2 watts when turned off, but only 1 watt when on
but not getting a signal from the computer. Odd, but it's probably
an anomaly of the measurements. When the screen is active, the
power draw is 37 watts.
Add these together and you get 3 watts with everything turned
off but not unplugged and 4 watts while in standby. That jumps
to 146 watts when sitting there quiescent but powered up. Using
10 cents per kilowatt hour as a total electric bill price, which
is not untypical and makes the math easy, we can calculate what
this computer costs. With the computer system off half the day,
it burns about 1 KWH a month or 10 cents worth of power just
for being plugged in. If left on active the other half of the
day, it pulls an additional 1,752 watts or about 53 KWH per month
at a cost of $5.26. That's about $63 a year. If it was on standby
and not active that entire half the day, the cost would be only
14 cents a month. But, obviously, that's not realistic. There
needs to be an appropriate mix of power levels.
The best compromise is to turn off the computer and monitor
for long stretches of time overnight or away from the office.
Then set the machine to standby when it is not being used for
short periods and hibernate for longer periods. The difference
is that hibernate saves your working information to disk but
takes longer to come back on. You can make these settings by
right clicking on an unused part of the screen, selecting properties,
screen saver and then power schemes. You can also get to these
settings through the control panel. I've got the monitor set
to turn off after 5 minutes and the system to go into standby
after 15 minutes and hibernate after 2 hours. Pushing the power
button on the PC will also send it into standby immediately if
I know I'm going to be gone awhile. You can choose your own settings
to match the way you work.
Granted, these measures aren't going to save a fortune, but
it's money that would otherwise be going down the drain for no
good reason. It's also power draw on the grid that encourages
the electric company to think about building more coal fired
power plants, belching more greenhouse gases and assuring additional
future rate hikes. There is no sacrifice involved here. The computer
will automatically shift into a lower power mode anytime it is
being ignored and come back to life pretty quickly when needed.
Now consider this micro experience on a macro basis. How about
corporations running thousands of PCs, with many of them just
sitting there glowing at full power while their users are in
endless staff meetings or off having lunch. You can see how 150
Watts become 150 KW pretty easily. That's thousands of dollars
a month and tens of thousands of dollars a year. All for nothing
of value. Add in the cost of air conditioning to remove the heat
generated by those active but unused computers and the price
goes even higher. Just remember that Power = Money, even though
you may have heard it the other way around.
Magazines and Books of Interest:
Home PowerMagazine is the perfect introduction
to alternative energy for the individual. See how practical it
is for you to join the alternative energy revolution on a personal