For
many years now, I've been shutting off my computer at night. But
I'm now convinced you can leave your computer on at night and still
conserve as much energy. (by Monte Enbysk)
If you're a Windows user (Windows 98 Second Edition
or beyond), just set up your PC to "hibernate" overnight.
"Hibernate" powers down your monitor to about 5 watts
of energy and your PC to 2.3 watts — virtually the same as
turning your PC off (your monitor uses zero watts when turned off;
more on this below). Either way, you save as much as $90 a year
in power costs compared to a PC left on with a 3D screen saver running.
"Well, duh. Welcome back from the Disco Era,"
many of you are thinking. You already knew all this.
Maybe so, but the question keeps coming up, year
after year: Should you shut your computer down at night or leave
it running? Some time ago, I touched on the issue at the end of
this column. I essentially passed on the recommendation of the good
folks at Energy Star, a product-labeling program sponsored by the
U.S. Environmental Protection Agency, that "if you are going
home for the day, turn it off."
"Andy in Austin" recently triggered
my interest in revisiting the subject by raising the question in
tech guru Kim Komando's weekly e-mail newsletter. "Should I
shut my computer down at night? Or is it better to leave it running?"
he asked. Komando's response, in a nutshell: "The truth is,
it really doesn't matter."
The truth is, if you use the "hibernate"
feature of Windows XP (and previous versions from Windows 98 Second
Edition on), or even the "sleep" feature of most new Dell
PC models, it really doesn't matter much. Even the folks at Energy
Star agree you save almost as much energy as you do turning off
your computer for the night (minus unplugging it). And you won't
have to endure a lengthy "re-booting" process the next
morning; your computer should "wake up" in 30 seconds
or less.
Again, I may not change my habits. I like the
security of having it off (though locking your system or logging
off is just as secure), and I like the ability to shake the cobwebs
from my system on a daily basis. But, with every minute I spend
booting up in the morning, I can see why someone would rather leave
their machine on.
Turn it off, they still say
Full disclosure: Those at Energy Star still prefer that you turn
your computer off at night, for maximum energy savings. "We
are all about energy savings, and when you shut off your computer
at night, you save the most energy," says Craig Hershberg,
program manager for office equipment and consumer electronics. "Every
little bit helps. It all adds up."
But Energy Star supports the practice of putting
computers in "hibernate" or "sleep" mode —
most new Dell desktop PCs contain "sleep state" power-management
programs that work similarly as "hibernate." Energy Star
applauds companies such as Cisco Systems and Pitney Bowes that have
made enabling computers to "hibernate/sleep" at night
a company policy. (The organization recently issued press releases
touting the dollar volumes in energy savings at each company.)
Hershberg estimates that as many as 50% of U.S.
users are enabling their PCs to "hibernate/sleep" at night,
a percentage Energy Star hopes will continue to climb — even
if the users are doing it for the wrong reasons. Many users simply
don't like the 3-8 minutes it takes to re-boot a shut-off computer;
they're more concerned about the re-boot time than saving energy.
For that reason, and because the power-management features in Windows
continue to be improved, "the trend is for fewer people to
be shutting off their computers at night," he says.
However, here are some consumer "myths"
that are worth addressing:
Turning your PC off uses more energy than leaving
it on. Not true. The small surge of power you use when turning it
on — which varies per PC make and model — is still much
smaller than the amount you use in keeping it on for lengthy periods.
Turning your PC on and off wears it out. Five
or more years ago, there was something to this, but not today, say
Hershberg and others. It used to be that PC hard disks did not automatically
park their heads when shut off, and that frequent on/off cycling
could damage the hard disks. Today's PCs are designed to handle
40,000 on/off cycles before a failure, and that's a number you likely
won't reach during the computer's five-to-seven-year life span.
Screen savers save energy. Not true. Screen savers,
at a minimum, can use 42 watts; those with 3D graphics can use as
much as 114.5 watts, according to Don McCall, a Dell product marketing
manager who does power measurement studies for the PC manufacturer.
"It's absolutely wrong thinking that a screen saver will save
energy," he says.
Your computer uses zero energy when "off."
That's true only if it is unplugged. Otherwise, the PC utilizes
"flea power," or about 2.3 watts, to maintain local-area
network connectivity, among other things, McCall says. In "hibernate"
mode, your PC uses the same 2.3 watts; in "sleep" mode,
your PC uses about 3.1 watts. Monitors do use zero energy when turned
off.
Lab tests done by Dell show that a PC running
Microsoft Office uses 42.7 watts, McCall says. If it runs continuously
at that rate for 365 days, at 7 cents per kilowatt-hour, the power
consumption costs would be $26.18 for the PC and $45.99 for a regular
monitor, for a total of $72.17 for the workstation.
Flat-panel monitors use less energy (22 watts
when left on, 3.3 watts in "sleep" mode) than regular
monitors (75 watts when left on, 5 watts in "sleep" mode),
McCall says. So the same workstation with Microsoft Office running
for a year would use $39.67 in power with a flat panel.
Meanwhile, if a PC was kept in "sleep"
mode for 20 hours, for every four hours "on," as Dell
recommends, the annual energy costs per PC would total $16.17 with
a regular monitor and $9.88 with a flat panel. Using "hibernate,"
the costs would be slightly cheaper.
Enabling "hibernate"
As I said, "sleep" mode is available
on most new Dell PCs, while "hibernate" is available to
any user with Windows XP and previous versions (from Windows 98
Second Edition on). To enable "hibernate," simply go to
your Control Panel, click on "power options," and set
your PC to "hibernate" after a specified time (most recommend
30 minutes).
If you are away from your PC a lot during
the work day, you may want to set it to "hibernate" after
45 minutes to an hour, and set it to "standby" to 15 minutes.
Under "standby," you'll be conserving power but you won't
be saving your computer memory onto your hard disk, as you will
with "hibernate." "Standby" is meant for shorter
absences. |