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"
Watts: The rate of consumption (like how "miles per hour" is a rate).
Watt-hours: The amount of energy used (like how "50 miles" tells you the distance traveled.
Electrical usage is measured in either watts (the rate
at any instant), or watt-hours or kilowatt-hours (the
total amount used). 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.