How to misquote this site
and how to misinterpret the calculator results
Probably better than half of the people who
quote figures from this site in newspaper articles and blogs
make some
kind of
mistake — either minor or major. So readers are
likely
misinterpreting the
results, too. So here's a rundown of the
most common mistakes, so you can make sure you're not going down
the
wrong path. This
page is really a primer on how to quote and use the
site
correctly, not
how to misquote and misinterpret it, but the
provocative title of this page gets
more people to read it. You're here, aren't you?
Anyway,
let's get started. But first, let me remind members of the
media
that I'm available for
interviews and
to check your articles for accuracy before you run them.
Take me
up on it, it's free.
Electric
rates vary widely!
You can't quote electrical costs without
knowing the price of electricity, and everyone's rate is
different.
I've found rates ranging from 12¢ to 50¢ per kWh from the
same
provider! So writing, "Mr. Electricity says it costs
50¢ to
dry a load of clothes in an electric dryer" is wrong, because
that's
not what I say. More accurate is, "It costs about 50¢ to
dry a
load
of clothes in an electric dryer, assuming a rate of
15¢ per
kWh."
There's really no such thing as a "typical" or
"normal" rate for electricity. But I have to use something
for the
examples on this site, so I
use 15¢, which is a reasonable example, but
not
necessarily "typical" or "normal", and certainly not
average.
Let's see why average rates aren't a good choice for examples.
Most
utility rates are tiered, meaning that excessive use
is billed
at a higher rate. This is important
because your savings are also figured at the highest
rate
you're paying. For example, let's say you pay 9¢/kWh for
the
first
500 kWh, and then 15¢/kWh for use above that. If you
normally use
900 kWh a month, then every kWh you save reduces your bill by
15¢. (Well, once you get your use below 500 kWh, then your
savings will be 9¢ kWh, but you get the point.) Some
utilities
have four or five tiers, with the rate getting ever higher the
more you
use.
To find your own savings, you should generally
choose the highest rate you're currently paying, because
that's
the rate you'll start saving at. Don't use the average
rate. To find your highest rate, just look at your
bill.
For more information about how you're billed, see the page on the
cost of electricity.
Wrong |
Borderline |
Best |
Why |
"It costs 50¢ to dry a load of clothes in an electric dryer." | "An electric
dryer often costs around 50¢ per load." |
"It costs about
50¢ to
dry a load of clothes in an electric dryer, assuming a
rate of 15¢ per
kWh." |
Everyone's cost
of electricity is different. Rates
can vary from 12¢ to 50¢ per kWh from the same
provider. |
"...using the
average rate of 15¢ per kWh..." |
"...using a
typical rate of 15¢ per kWh..." |
"...assuming 15¢
per kWh..." (or) "...using a rate of 15¢ per kWh..." |
15¢ is not the
average rate in the U.S. It's hard to say whether it's
"typical", since
we're not sure there really is a "typical" rate, but
that's better than
saying "average", which is clearly wrong. The easy
way out is to
just not identify the rate as average or typical, just
list the rate
you're
assuming. |
"...using the
average rate of 12¢ per kWh..." |
"...assuming 15¢
per kWh..." (or) "...using a rate of 15¢ per kWh..." |
While 12¢ is the
national average, the average is a poor choice for
examples, since
savings are realized at the highest tier someone is
paying, which is
usually more than the average. |
|
"Electricity
costs 14¢ per kWh in New York." |
"The average
price of electricity in New York was 14¢ per kWh in
2003." |
Whenever I list
a price for a state I clearly identify it as an average
for the
whole state. As I keep saying, everyone's rate
is different. |
Device
wattages are just examples!
Different models use different amounts of
electricity.
Not every computer uses the same amount of
juice, and not every TV does either. I thought this would
be
obvious, but from the reader mail I get, apparently it's
not. So
please don't think that the examples on this site are
accurate
for your particular computer,
TV, or whatever. You'll need to measure
the
wattage of your device to get accurate results for the
model
you actually own.
Wrong |
Better |
Why |
"Mr. Electricity says a 42" plasma TV uses 240 watts." | "Mr. Electricity says a typical [or average] 42" plasma TV uses around 240 watts." | Different models
use different amounts of juice! Also, my figures
are usually the average
for all models, which is a little different from
"an average TV",
but I know you have to say something, and this
is close enough. |
Some
devices use less than their rated wattage
Some devices don't run at full power all the
time.
For example, I list a water heater at 3800 watts, but
the water heater doesn't run continuously. It shuts off
when the
water gets hot enough. Then there are devices that use
energy
according to how hard you run them — a stereo uses more power
the
louder you set it, and less power the lower you set it.
Likewise,
I list a microwave oven at 1440 watts, but that's only if it's
running at the highest setting. (Plus, the top setting on
your
microwave could be less than 1440 watts, as mentioned
above.) So
realize that things like heaters and AC's don't actually run
continuously, and things like stereos and microwave ovens don't
always
run at full power. For most of the other items it's safe
to use
the listed wattage. By the way, I solved the problem of
refrigerators not running continuously by listing the average
wattage for fridges in the calculator (and identifying it as
such).
Wrong |
Better |
Why |
"An electric water heater uses 3800 watts. So in 24 hours it uses 24x3800= 91,200 watt-hours." | "An electric
water heater uses 3800 watts, but it doesn't run
continuously. A typical family might pay around
$40.48/mo. to run their
heater." |
Some
devices, like water heaters, don't run
continuously. So you can't
just multiply their rated wattage times the number of
hours you're
using them. |
"A microwave
oven uses 1440 watts. If you use a microwave for 10
minutes a day for
30 days, that's 7.2 kWh." |
"A 1440-watt
microwave used on the highest setting for 10 minutes a
day for 30 days
uses 7.2 kWh." |
First, some ovens are
more powerful than others, and therefore use more
energy. 1440 watts is the upper end, some ovens
use less. And whatever the top setting is on the
microwave, it can be run at a lower power level.
So, we need to identify the size of the oven (in watts),
and If we're assuming
that use is at the highest level, we need to say so. |
"A typical dryer consumes about
5,000 watts." (eHow) |
"An electric dryer costs about
$0.43 a load at a sample rate of 15¢/kWh." (or...) "An electric dryer uses about 3.3 kWh for a 45-minute load." |
First,
if we're talking about an electric dryer (vs. a gas
dryer), we need to
say so. Next, as with most appliances, dryer
wattage varies by
model, from about 4000 to 6000 watts. But most
importantly,
knowing the wattage isn't that helpful in the first
place. What
the reader really wants to know is the cost per load
(or the
kWh per load, so they can calculate the cost using their
own local rate
for electricity). |
Be
especially careful when figuring clothes washer or dryer costs
The clothes washer/dryer results were so
frequently misunderstood that I removed them from the
general-purpose
calculator, and
now the calculator gives the results an a per-load basis, which
is more
meaningful. I
also refer calculator users to the pages on the site which cover
washer/dryer costs in detail. Unfortunately people still
sometimes misquote the laundry figures. In some cases I
have no
idea how they came up with their results, or in other cases
they're
using the wrong table. (One table shows the total cost of
electric +
water, one shows just the electric cost without water.)
Then
there's the common case of not acknowledging the
assumptions:
Your laundry cost will vary from my examples
by quite
a lot if your local fuel and water rates, water heater
temperature,
and groundwater temperature vary very much from my examples.
So
if
you're figuring your laundry costs, be extra careful, since this
is an
area where frequent mistakes are made for some reason. So
the
previous section for an example.
There
is no such thing as "watts per hour"
Electrical usage is measured in either watts
(the rate at any instant), or watt-hours or kilowatt-hours
(the
amount used in an hour).
Thus, a 100-watt light bulb uses 100 watts, or 100 watt-hours in
an
hour. It does not use "100 watts per hour", since there is
no
such animal. That's like saying you weigh 150 pounds per
hour. Likewise, you don't pay for electricity by the
kilowatt,
you pay for it by the kilowatt-hour. See more on
how electricity is measured.
My
figures are almost never "as much as"
I rarely tell you the maximum
amount you could save. That's not as helpful as
telling you
the typical, realistic
savings, so that's what I do. So when someone says, "Mr.
Electricity says you can save as much as $150 a year from
washing in
cold instead of hot," that's wrong. You could actually
save much
more than that, but $150 is realistic, using good figures
for the
assumptions.
My
name is Michael Bluejay, not Michael BlueJay
The J isn't capitalized. This is
easy to get right, since my name is spelled correctly all over
my
site. This was too much a challenge for Reuters
to get right, though. And whenever any reporter can't
spell my
name right, expect them to get something else wrong, too (like
Reuters
did). While I'm at it, there's no "www" in my web address,
either; almost everyone adds the www, even though it doesn't
appear in
the browser's address bar.
Examples
of getting things wrong
WCPO
Channel 9, May 2011
- They quote an electric rate of 10¢ "a kilowatt". First, electricity is charged by the kilowatt-hour, not the kilowatt, and second, 10¢ is too low as a sample rate, and is actually less than the national average. I'm currently using 15¢/kWh on this site.
- They say a coffeemaker running at 6 watts when idle
costs $1.25/mo., assuming the 10¢ rate. In fact it
would cost
only
$0.44/mo.. (6 watts x 24 hrs/day x 30.5 days/month ÷
1000 kw/w x
10¢).
- "A few cell phone chargers now shut off when the
phone is unplugged, though most don't." Actually, it's
the
opposite. Even my ancient 2004-era LG VI-5225 charger
shuts off
when the phone is unplugged. Even if
the charger doesn't shut off, the piddling 0.x watts it
would use
should be the
least of your concerns, as I explain on the energy
vampires page.