Mr. Electricity is your guide to saving energy in your home.
We're recommended by the government of Berks County, PA.
Related sites:
Watt Watt. News about efficiency and conservation, written by readers of the site.
Home Power Magazine. All about renewable energy for the home.
Thin House. Blog about a family committed to cutting its energy use by 80%.
No-Impact Man. Blog about a family striving to have no net impact. (i.e., What little they use, they offset.) Inspirational.
Off-Grid. News and resources about living without being connected to a utility company.
|
If you like this site, you might also like some of my
other sites:
Battery
Guide
Which battery is best? We cover
rechargeable and alkaline batteries to show you what's hot,
what's not, and the best way to charge them. (visit
now)
|
|
Vampire power!
(aka
standby power)
Things
that use electricity even when they're
off
By now you've probably heard
that lots of electronic equipment (like a TV) uses some
electricity even when it's off. Is the amount
significant? Yes. It's not the biggest part of your bill,
but since it's possible to save energy here, you might as
well. Vampire power accounts for about 5% of household
electricity use in the U.S., and 10-15% in Japan, Germany,
and the Netherlands. (EPA,
accessed 7/08)
Vampire power per device isn't very much -- typically
5-10 watts at most. And its going down fast, as various
countries have started to require that vampire power be no
more than 1 or 2 watts on new devices.
(ACOEL)
In fact, CNET
stopped including the amount of standby power in their TV
wattage table because nearly every TV they tested was <1
watt in standby mode. Standby is only a problem if your
devices or old, or you have a lot of them (or you're super
anti-wasteful like me and can't stand the idea of something
drawing any power if it's not being used).
There are two kinds of things that use vampire
power:
- Devices in
standby. When you grab your TV's remote
control and press ON, the TV has to be getting a little
juice already so it can receive that ON signal and
respond to it. It's "standing by" waiting for you to turn
it on with the remote. That's where we got the term
"standby power". Other things that use standby power
because they're waiting to respond to a button press are
DVD players, stereos, and microwave ovens.
- Plug-in adapters.
These are the big blocks that convert AC to DC.
Most of them are cheaply made and continue to draw some
electric even when the device they're powering is turned
off (or in the case of a cell phone, even when the phone
is fully charged). If the adapter is warm even when the
device is off, it's using phantom power. It's usually not
much, but it could be as much as 10 watts.
Let's do an example. You turn your TV off, but it
continues to draw some power so it can respond to the remote
control when you press the ON button. The standby amount is
our example is 10 watts, on the high side. From our
cost page page we can see how to
estimate the cost:
- 10 watts x 24 hours/day x 30.44 days/mo. = 7306
watt-hours
- 7306 watt-hours = 7.3 kWh
- 7.3 kWh x 11¢ = $0.80/mo.
So one 10-watt TV isn't gonna put you in the poorhouse
any time soon. But you might have lots of devices, or
some devices that use even more than 10 watts. That's why
standby power accounts for 5% of U.S. household use on
average.
 How
to combat vampire power
- When buying a new device, get a low-vampire-power
version. Look for the EnergyStar label. Failing that,
look for the specs on the device. Or take a watt-hour
meter with you and measure it in the store.
- Test the devices you
already own to see if they're using too much
standby power. If they're not using much, then
there's not much point in doing the steps below to combat
standby power. Ten devices using 1 watt of standby cost
less than $1/mo. to run, at average electric
rates.
- Unplug devices and adapters when you're not using
them. This method is free but inconvenient. If you
want convenience you can have it for a few bucks, as the
next few items show...
- For one or two items, get a flip switch. The
one pictured at right is one of my favorites.
It cost me all of $1.99.
- For a two or more devices that will be on or off
at the same time, use a simple power bar with a
switch. The one pictured at left was four bucks at
Home Depot. Oh, so easy.
- For several devices that you want to switch
separately, get a power strip with individual
switches. While these are ubiquitous in other
countries like Japan, they're hard to find in the U.S.
But never fear, I
found one for you, pictured at right, and it's
only $17. If you prefer something more industrial or
rack-mountable, there's the $25 GemSound SP-8500.
- For computer systems, you might like the
Bits
Smart Strip. It's a special power strip
that automatically cuts power to all your peripherals
when you turn off your computer. Me, I prefer the SP-8500
above, because then I can keep my scanner and printer off
while the computer is on, turning them on only when I
actually need to use them.
- An interesting product called Bye
Bye Standby ($25) lets you turn power on and
(completely) off using a remote control. This is
handy if you have only a couple of items to manage, and
if the plug isn't in a convenient place for a switch.
They also have a U.K.
site.
More energy to run the clock than
the device?
When we talk about the "energy to run the clock" in a
microwave or VCR we're not really being fair, because the
standby power does more than just run the clock. It
keeps a microwave ready to respond to any button you press,
and keeps a VCR ready to respond to the ON button on the
remote control (or your instructions to automatically come
on at a certain time to record a program). But we're being
unfair today, so we'll talk about the power to run the
clock, as though that were the only thing going on when the
device is off.
Okay, so my VCR uses 5 watts when it's "off", 12 watts
when it's "on", and 18 watts when it's actually playing a
tape. Let's say I play tapes for an hour a day, and
otherwise it's off.
- ON: 1 hour x 12 watts = 12
watt-hours
- OFF: 23 hours x 5 watts = 115
watt-hours
Yes, the clock uses more energy than the device itself.
Way more.
Is the same true of the microwave? It depends on how much
you use it, and how powerful your microwave is.
- ON: 10 minutes x 1000 watts = 167
watt-hours
- OFF: 23 hours, 50 minutes x 7 watts =
167 watt-hours
So in this case the clock uses more energy than the
oven if you use the oven for less than 7 minutes a day.
(This is an example because your own microwave likely
uses a different amount of energy when it's on and when it's
in standby. The numbers above aren't true for all
microwaves.)
When energy-efficient
appliances aren't
My old Apple Personal Laserwriter 300 was
touted as being a modern energy-efficient appliance.
It didn't even have an power switch! Apple designed it to
automatically go into low-power mode when it wasn't being
used, consuming only five watts of power.
If you were the kind of person who never turned off
your printer, then this would definitely save a lot of
energy -- most of the time you'd be using only five watts
instead of several hundred. But if you're the kind of
person who shuts things off when you're done with them,
then all of a sudden this energy miser is really an
energy waster. It sucks five watts of power 24/7, whether
you're using it or not.
I solved this problem by putting it on a switchable
power strip.
Sample standby power
amounts
- 10.4W - Printer &endash; HP Laser Jet
2200d
- 8.2W - Router &endash; Netgear DG834PN
- 2.8W - Monitor &endash; Dell 1907FPT, Elite
Group EZX15G
- 1.6W - Phone Charger &endash; Samsung phone
charger for D900
- 0.4W - iPod charger
Here's a site that has a big
list of standby power usage per device.
This page last updated July
2009.
|
