Online Home Energy Analysis
Calculating energy use based on a description of your own house and appliances
can help identify the best opportunities for energy savings.
For a quick and easy way to find out how your home energy use compares
with the average, try the ENERGY STAR Home
Energy Yardstick. You will need to enter some common information
about your home such as age, square footage, number of occupants and
energy bill totals for a consecutive 12-month period. You can access
your bills online by going to My Account.
For a more detailed analysis, use the U.S. Department of Energy's Home
Energy Saver. Users can begin the process by simply entering their
zip code, and in turn receive an instant initial estimate. By providing
more detailed information about your home, you can receive increasingly
customized results along with energy-saving upgrade recommendations.
Energy Use of Some Typical Home Appliances
Knowing how much electricity each of your appliances uses will also give
you a clearer picture of where your energy dollar is going. Powered with
this knowledge, you can use energy more efficiently and
have greater control over your energy budget.
If you want an estimate of how much electricity your home appliances consume, refer to
the Household Appliances list below. If you want a more exact estimate,
you can generally find the wattage stamped on the bottom or back of the appliance, or
on its "nameplate." The wattage listed is the maximum power drawn by the appliance.
Since many appliances have a range of settings (for example, the volume on a radio), the
actual amount of power consumed depends on the setting used at any one time.
Use the following formula to estimate the amount of energy a specific appliance consumes:
Wattage x Hours Used Per Day = Daily Kilowatt-hour
(kWh) consumption (1 kilowatt (kW) = 1,000 Watts)
Multiply this by the number of days you use the appliance during the year for the annual
consumption. You can then calculate the annual cost to run an
appliance by multiplying the kWh per year by the cost per kWh consumed. Refer to your
most recent energy bill for the latest kilowatt-hour rate.
Aquarium = 50-1210 Watts
Clock radio = 10
Coffee maker = 900-1200
Clothes washer = 350-500
Clothes dryer = 1800-5000
Dishwasher = 1200-2400 (using the drying feature greatly increases
Dehumidifier = 785
Electric blanket - Single/Double = 60 / 100
Ceiling fan = 65-175
Window fan = 55-250
Furnace = 750
Whole house fan = 240-750
Hair dryer = 1200-1875
Heater (portable) = 750-1500
Clothes Iron = 1000-1800
Microwave oven = 750-1100
CPU - awake / asleep = 120 / 30 or less
Monitor - awake / asleep = 150 / 30 or less
Laptop = 50
Radio (stereo) = 400
Refrigerator (frost-free, 16 cubic feet) = 725
19" = 110
27" = 113
36" = 133
53"-61" Projection = 170
Flat Screen = 120
Toaster = 800-1400
Toaster oven = 1225
VCR/DVD = 17-21 /20-25
Vacuum cleaner = 1000-1440
Water heater (40 gallon) = 4500-5500
Water pump (deep well) = 250-1100
Water bed (w/ heater, no cover) = 120-380
Refrigerators, although turned "on" all the time, actually cycle on and off at
a rate that depends on a number of factors. These factors include how well it is insulated,
room temperature, freezer temperature, how often the door is opened, if the coils are
clean, if it is defrosted regularly, and the condition of the door seals. To get an approximate
figure for the number of hours that a refrigerator actually operates at its maximum wattage,
divide the total time the refrigerator is plugged in by three.
If the wattage is not listed on the appliance, you can still estimate it by finding the
current draw (in amperes) and multiplying that by the voltage used by the appliance. Most
appliances in the United States use 120 volts. Larger appliances, such as clothes dryers
and electric cooktops, use 240 volts. The amperes might be stamped on the unit in place
of the wattage. If not, find a clamp-on ammeter—an electrician's tool that clamps
around one of the two wires on the appliance — to measure the current flowing through
it. You can obtain this type of ammeter in stores that sell electrical and electronic
equipment. Take a reading while the device is running; this is the actual amount of current
being used at that instant.
Note: When measuring the current drawn by a motor, in the first second that the motor starts,
the meter will show about three times the current than when it is running smoothly.
Also note that many appliances continue to draw a small amount of power when they are switched
"off." These "phantom loads" occur in most appliances that use electricity,
such as VCRs, televisions, stereos, computers, and kitchen appliances. Most phantom loads
will increase the appliance's energy consumption a few watts per hour. These loads can
be avoided by unplugging the appliance or using a power strip and using the switch on
the power strip to cut all power to the appliance.