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)
|
The
Military Budget as Cookies
This excellent animation from TrueMajority shows in
graphic detail (using Oreo cookies) how ridiculously, large
the military budget is, and how we could solve many domestic
problems with a modest 12% cut. A must-see. (watch
it now)
|
|
|
Energy
used by cooking
Let me be perfectly clear:
Most
people can't save much energy by
changing their cooking methods --
especially compared to other ways
of saving energy.
You'll save a lot more energy
by:
I provide this page anyway
not because it's really useful,
but only because so many
people are curious about it.
Also note that if you're
trying to save money for
environmental reasons (rather
than saving money), what matters
more is
what
you eat rather
than
how
you cook
it.
Specifically, vegetarian
diets are more efficient, since
meat and dairy requires
tremendous amounts of energy to
produce. It takes 200 times more
fossil fuel to produce beef than
potatoes, for example.
(source)
Trying to figure out
the most energy-efficient way to
cook meat is therefore like
buying the most gas-guzzling SUV
you can find and then trying to
figure out the optimal speed to
drive it for the best fuel
economy. The real energy drain
was from getting the wrong
vehicle to begin with, not the
speed at which it's driven.
Likewise, if you buy meat, you've
already wasted way more energy
than you could save even by
eating the meat raw. Cooked
veggies requires less overall
energy than uncooked meat, every
time.
(more...)
How
much do various baking methods
cost? (oven-style
cooking)
As the table
shows, the difference between
most methods is
negligible.
|
|
Temperature
(degrees F)
|
Time
|
Energy
Used
|
Cost
|
|
Electric
oven
|
350
|
1 hr.
|
2.0 kWh
|
$0.24
|
|
Gas oven,
electric ignition
|
350
|
1 hr.
|
0.112 therm
+0.35 kWh
|
$0.21
|
|
Gas oven,
pilot
|
350
|
1 hr.
|
0.112
therm
|
$0.16
|
|
Electric oven,
convection
|
325
|
45 min.
|
1.39
kWh
|
$0.17
|
|
Toaster
oven
|
350
|
1 hr.
|
0.33
kWh
|
$0.04
|
|
Crockpot
|
200
|
7 hours
|
0.70
kWh
|
$0.08
|
|
Microwave
oven
|
High
|
15
minutes
|
0.36
kWh
|
$0.04
|
From Citizens
Campaign for the Environment, and
Home Energy 1993 and 2001.
Toaster oven is by my own
measurement.
Assumes $0.12/kWh
for electricity and
$1.47/therm
for gas
I suspect that the
figure for electric ovens
might be too high. I will
measure the actual use of an
oven some time and report it
here.
Note from the second row in
the table that gas ovens
use electricity! Electric
ignition ovens run a 350-watt
glow bar to keep the gas flame
going. (more...)
APS has a good table
showing the
efficiency of gas, electric,
and microwave ovens. The
efficiency doesn't tell you
the cost, though, because
different energy sources are
charged at different
rates.
Note that for someone
baking three hours a week,
the cheapest baking method
saves only $2.61/mo. compared
to the most expensive
method. This underscores
my point that focusing on
cooking methods is not the way
to save electricity, and you
should look at heating,
cooling,
lighting,
and laundry
instead.
Gas vs.
Electric Stoves /
Ovens
In general, gas is
cheaper than electric for
cooking, but there are
several caveats:
- "Cheaper" is a
relative term. The
average typical savings for
gas over electric cooking
is only $18/yr.
- Electric could be
cheaper where you live, or
in the future. The cost
of natural gas has
skyrocketed recently. Gas
used to be a much better
deal than it is now. Also,
gas could be more expensive
than electric in your area
right now.
- Running a gas line
negates the savings. If
you don't have already have
a gas line running to the
kitchen, the cost of having
one installed could easily
be more than you'd save by
switching to gas, even
after several years.
- The monthly gas
charge negates the savings.
If you don't already
have gas service, getting
gas service just to power a
gas stove will likely wind
up costing you way more
than continuing to use an
electric stove. That's
because you'll have to pay
~$10/mo. or so as a
"customer charge", just for
the privilege of being a
gas customer.
- Gas has other
drawbacks compared to
electric. For starters,
gas is dangerous
because it's combustible.
Remember the Hindenberg?
Imagine a similar explosion
in your house. True, most
people's kitchens don't
blow up, but some
of them certainly do.
Next, breathing the
products of gas combustion
is decidedly unhealthy.
Electricity doesn't have
that drawback. I choose
electric over gas for that
reason alone.
The problem with air
pollution from gas
ovens/stoves is so bad
that I found this in a
Whirlpool oven manual from
2003: "The health of some
birds is extremely sensitive
to the fumes given off [by
the oven]. Exposure to the
fumes may result in death to
certain birds. Always move
birds to another closed and
well ventilated room."
While the problem is
more serious for birds it
exists for people, too. A
study commissioned by the Air
Resources Board of California
showed that gas
ovens generate unhealthy
levels of combustion
byproducts like carbon
monoxide and nitrogen dioxide.
(It also showed that the
self-cleaning mode generated a
lot of indoor air pollution,
whether it was a gas or an
electric oven.) If you do use
gas, the Children's Health
Environmental Coalition has a
list of ways
to reduce gas pollution in
your home.
Cost of gas vs.
electric. The following
table compares the cost of
operating a gas vs. electric
stove/oven.
|
|
Gas
|
Electric
|
|
Model
|
Kenmore 30",
#73052
|
Kenmore 30",
#93052
|
|
Price
|
$350
|
$360
|
|
Avg. fuel
price
|
0.00147¢/BTU
($1.47/therm)
|
12¢/kWh
|
|
Burner
|
|
Energy use (1
hour)
|
9,000
BTU
|
2,500
watt-hours
|
|
Yearly cost
(2
burners x 10
mins./day
ea.)
|
$16.11
|
$36.53
|
|
Oven
|
|
Energy use (1
hour)
|
18,000
BTU
+ 350
watt-hours
|
2000
watt-hours
|
|
Yearly cost
(2
hours/week)
|
$31.89
($27.52
+
$4.37)
|
$24.96
|
|
Burner
+ Oven
together
|
|
Total YEARLY
cost
|
$48.00
|
$61.49
|
|
Prices
from Sears.com in
July 2006. Fuel rates
are U.S. national
averages in August
2009; see more on
electricity
prices
and gas
prices.
|
So gas is cheaper for
stovetop, and electric is
cheaper for oven baking.
Part of the reason is that in
modern gas ovens with electric
igniters, the igniters stay on
even after the oven is
lit.
Microwave ovens are
almost as cheap as running an
electric burner. For
baking, microwave ovens
and crockpots are cheaper than
both electric and gas
ovens.
There's also a new kind of
stovetop cooking called
induction
cooking, but I have no
good data and no unit to
test.
Energy
used by electric
ovens
The specs I've
seen for electric ovens have a
bake element of 2000 to 3500
watts with a maximum
temperature of 500
degrees. However,
different ovens should use
about the same amount of
energy to come up to and
maintain a given temperature
setting. My feeling is that
the higher-wattage ovens
simply get up to the desired
temperature faster, but don't
take any more energy to do so.
And whether the oven is
high-wattage or low wattage,
it's rare for the bake element
to run continuously at full
capacity. It either runs at a
lower power level or shuts
itself off for a few minutes
at a time in order to maintain
the desired temperature.
Estimates I've seen
elsewhere for an electric oven
set to 350° is 2.0 kWh
per hour, regardless of
the wattage of the bake
element. I suspect that this
might be a bit high, and I'll
do a direct measurement myself
when I have time. (I did
measure consumption in a
toaster oven at
350° and it used only
0.33 kWh in an hour.)
In the meantime, if you're
using the 2.0 kWh figure for
an oven, adjust up or down for
higher or lower
temperatures.
Broil elements are rated
higher than bake elements,
typically 3000 to 3600
watts. However, it's
unlikely that they run
continuously to maintain
temperature, so I think a
figure of 2400 watt-hours
per hour is a more
reasonable figure to use while
broiling.
Self-cleaning ovens use
energy at a much higher rate
when cleaning, because they
get much hotter than they do
for cooking. I couldn't
find any reliable figures for
the rate, but the Department
of Energy says that an oven
uses about 5.3 kWh per
cleaning cycle.
(DOE,
PDF)
Tips to
save on energy and costs when
cooking
- Remember that you can't
save much energy by changing
your cooking methods.
Cooking uses a fraction of
total household energy
compared to things like
heating, cooling, and
lighting.
The tips
below do work, but the savings
is minimal.
- Remember also that to
save energy for environmental
reasons,
the
real savings is from eating
vegetarian, not
obsessing over cooking
methods. It takes 200
times more energy to produce
beef than to produce potatoes.
(more...)
- Use a crockpot and a
microwave oven for baking.
These are the cheapest ways to
bake.
- Open the oven door only
when necessary. Oven
temperature drops 25-30
degrees every time you open
the door. Getting an oven with
an oven light and a glass
window in the door will let
you check on your food without
opening the door.
- Don't put aluminum foil
on the bottom of a gas oven to
catch drippings. The foil
blocks the heat that the oven
is trying to produce. (It's
fine to put foil in an
electric oven, as long as you
leave the heating elements on
the side exposed.)
- Use glass and ceramic
pans when baking. They
retain heat better than metal
pans and allow you to lower
the baking temperature by 25
degrees.
- Isolate the
kitchen. If the oven is on
for an hour or more, close
doors leading to the kitchen
to keep the kitchen from
heating up the rest of the
house. If you have a stove
exhaust fan, use it.
- Don't use pilot lights
on gas burners. Pilot
lights not only waste gas
24/7, they add heat to your
home. Eliminating pilot lights
means lower costs for cooling
since you'll run the A/C less.
Going pilotless will use 40%
less gas than normal.
(source)
If your existing stove already
has pilot lights, turn them
off and use a clicker-lighter
to light the burner when
you're cooking. (Turning them
off requires tightening the
set screw. You can't just blow
the pilot out, because then
gas will still be leaking out
the unlit pilot hole.)
Getting a new oven with
electric ignition instead of
pilot lights will make it easy
to save gas on the burners,
but you'll give up that
savings when using the oven
because the electric igniter
runs the whole time the oven
is on. (See the table at the
top of this page.)
Below are questions I've
received and answered about how
saving energy when cooking.
|
|
Questions about
saving energy when cooking
When my wife
wants a cut of hot water she heats up a
cup of cold water in the microwave. I keep
telling her that it is uses less power
from a financial standpoint to heat the
water in a teapot on our gas stove. She
doesn't believe me. Who is
right?
-- Anonymous,
Nov. 2004
There is no such thing as
"using less power from a financial
standpoint". You can use less energy,
or you can pay less money, but they're
two different things. Method A might
use less energy than Method B but could
still cost more if the kind of fuel it
uses were more expensive. Decide which
issue you want to argue with your wife
about: cost or efficiency. They're not
the same thing.
According to Home Energy Magazine,
gas stoves are only 40% efficient
compared to a microwave's 55%. But the
gas stove is cheaper to run because gas
is cheaper than electricity. The
microwave uses less energy, but the gas
stove is cheaper financially.
However, focusing on this won't save
you an appreciable amount of money
because the raw cost of using one
method vs. another isn't that great.
You'd see more savings by replacing one
light bulb with a CFL or turning off
the air conditioner on occasion.
Which uses
less electricity: boiling water with an
electric burner or boiling it in a
microwave oven?
-- Anonymous,
Nov. 2004
For all intents and purposes
the energy used is the same. I boiled
two cups of 86-degree water in a GE
microwave oven (Model JS1533BV001,
1995) and it used 0.087 kWh. Boiling it
in a pot on an electric burner used
0.095 kWh. While there's a difference
it's not statistically significant,
especially given how crude my testing
methods were. Even assuming that these
figures are completely accurate, then
boiling two cups of water every day for
a year would use only 2.92 kWh extra
with the electric burner, or less than
$0.30 for the whole year.
While looking at this issue might be
interesting it's not useful for saving
electricity. Whichever is more
efficient, the difference isn't going
to be that great. Focusing on this
won't save you an appreciable amount of
energy. You'd save more energy over the
year by replacing one light bulb with a
CFL or turning off the air conditioner
for an hour. (Not an hour a day, one
hour at some point over the whole
year.)
Note that when boiling water, don't
boil more than you need. If you boil 3
cups of water in a kettle when you need
only 1 cup for tea, you've used 3 times
as much energy as you needed to.
[Note: Since I originally
answered this question, a reader
pointed us to Home
Energy Magazine's report on boiling
water using various methods, which says
that electric burners use 25% less
electricity than microwaves, though
their chart shows that the energy use
is about the same. They also point out
that if you boil only a mug of water in
the microwave vs. a whole kettle on the
stovetop, the microwave is going to be
cheaper. Again, this is academic,
because the difference between one
method vs. the other pales in
significance to the savings you'd get
by using CFL light bulbs or turning off
your AC for a day.]
|
|
Page last updated: November 2009
|
