If you're trying to decide whether to invest in a more energy-efficient appliance or you'd like to determine your electricity loads, you may want to estimate your home appliance energy consumption.
The formula for estimating energy consumption is below.
(Wattage × Hours Used Per Day ÷ 1000 = Daily Kilowatt-hour (kWh) consumption
Note: (1 kilowatt (kW) = 1,000 Watts)
You can use this formula to estimate the energy use for your home appliances and home electronics. Multiply this by the number of days you use the home appliance or home electronic during the year for the annual energy consumption. You can then calculate the annual cost to run a your home appliance or home electronic by multiplying the kWh per year by your local utility's rate per kWh used.
Note: To estimate the number of hours that a refrigerator actually operates at its maximum wattage, divide the total time the refrigerator is plugged in by three. Refrigerators, although turned "on" all the time, actually cycle on and off as needed to maintain interior temperatures.
See below for two examples of how to use the home appliance and electronics energy consumption formula.
Window fan:
(200 Watts × 4 hours/day × 120 days/year) ÷ 1000
= 96 kWh × 8.5 cents/kWh
= $8.16/year
Personal Computer and Monitor:
(120 + 150 Watts × 4 hours/day × 365 days/year) ÷ 1000
= 394 kWh × 8.5 cents/kWh
= $33.51/year
You can usually find the wattage of most appliances stamped on the bottom or back of the home appliance or home electronic, 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.
If the wattage is not listed on the home appliance or home electronic, 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 ovens, use 240 volts. The amperes might be stamped on the unit in place of the wattage. If not, find a clamp-on ammeter, which is an electrician's tool that clamps around one of the two wires on the appliance, to measure the current flowing through the appliance or electronic. 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.
When measuring the current drawn by a motor, note that the meter will show about three times more current in the first second that the motor starts than when it is running smoothly. 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 watt-hours. You can avoid these loads by unplugging the appliance or using a power strip and using the switch on the power strip to cut all power to the appliance.
To help you calculate the estimated energy use for your home appliances and home electronics we have provided you a list of the typical wattages for various home appliances and home electronics. Here are some examples of the range of nameplate wattages for various household appliances and electronics:
Aquarium = 50 – 1210 Watts
Clock radio = 10 Watts
Coffee maker = 900 – 1200 Watts
Clothes washer = 350 – 500 Watts
Clothes dryer = 1800 – 5000 Watts
Dishwasher = 1200 – 2400 Watts (using the drying feature greatly increases energy consumption)
Dehumidifier = 785 Watts
Electric blanket- Single/Double = 60 / 100 Watts
Ceiling Fans = 65 – 175 Watts
Window Fans = 55 – 250 Watts
Whole house Fans = 240 – 750 Watts
Hair dryer = 1200 – 1875 Watts
Heater (portable) = 750 – 1500 Watts
Clothes iron = 1000 – 1800 Watts
Microwave oven = 750 – 1100 Watts
Personal computer - awake / asleep = 120 / 30 or less Watts
Computer monitor - awake / asleep = 150 / 30 or less Watts
Laptop = 50 Watts
Radio (stereo) = 70 – 400 Watts
Refrigerator (frost-free, 16 cubic feet) = 725 Watts
19" television = 65–110 Watts
27" television = 113 Watts
36" television = 133 Watts
53"-61" Projection television = 170 Watts
Flat screen television = 120 Watts
Toaster = 800 – 1400 Watts
Toaster oven = 1225 Watts
VCR/DVD = 17–21 / 20–25 Watts
Vacuum cleaner = 1000 – 1440 Watts
Water heater (40 gallon) = 4500 – 5500 Watts
Water pump (deep well) = 250 – 1100 Watts
Water bed (with heater, no cover) = 120 – 380 Watts
Source: EERE
The formula for estimating energy consumption is below.
(Wattage × Hours Used Per Day ÷ 1000 = Daily Kilowatt-hour (kWh) consumption
Note: (1 kilowatt (kW) = 1,000 Watts)
You can use this formula to estimate the energy use for your home appliances and home electronics. Multiply this by the number of days you use the home appliance or home electronic during the year for the annual energy consumption. You can then calculate the annual cost to run a your home appliance or home electronic by multiplying the kWh per year by your local utility's rate per kWh used.
Note: To estimate the number of hours that a refrigerator actually operates at its maximum wattage, divide the total time the refrigerator is plugged in by three. Refrigerators, although turned "on" all the time, actually cycle on and off as needed to maintain interior temperatures.
See below for two examples of how to use the home appliance and electronics energy consumption formula.
Window fan:
(200 Watts × 4 hours/day × 120 days/year) ÷ 1000
= 96 kWh × 8.5 cents/kWh
= $8.16/year
Personal Computer and Monitor:
(120 + 150 Watts × 4 hours/day × 365 days/year) ÷ 1000
= 394 kWh × 8.5 cents/kWh
= $33.51/year
You can usually find the wattage of most appliances stamped on the bottom or back of the home appliance or home electronic, 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.
If the wattage is not listed on the home appliance or home electronic, 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 ovens, use 240 volts. The amperes might be stamped on the unit in place of the wattage. If not, find a clamp-on ammeter, which is an electrician's tool that clamps around one of the two wires on the appliance, to measure the current flowing through the appliance or electronic. 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.
When measuring the current drawn by a motor, note that the meter will show about three times more current in the first second that the motor starts than when it is running smoothly. 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 watt-hours. You can avoid these loads by unplugging the appliance or using a power strip and using the switch on the power strip to cut all power to the appliance.
To help you calculate the estimated energy use for your home appliances and home electronics we have provided you a list of the typical wattages for various home appliances and home electronics. Here are some examples of the range of nameplate wattages for various household appliances and electronics:
Aquarium = 50 – 1210 Watts
Clock radio = 10 Watts
Coffee maker = 900 – 1200 Watts
Clothes washer = 350 – 500 Watts
Clothes dryer = 1800 – 5000 Watts
Dishwasher = 1200 – 2400 Watts (using the drying feature greatly increases energy consumption)
Dehumidifier = 785 Watts
Electric blanket- Single/Double = 60 / 100 Watts
Ceiling Fans = 65 – 175 Watts
Window Fans = 55 – 250 Watts
Whole house Fans = 240 – 750 Watts
Hair dryer = 1200 – 1875 Watts
Heater (portable) = 750 – 1500 Watts
Clothes iron = 1000 – 1800 Watts
Microwave oven = 750 – 1100 Watts
Personal computer - awake / asleep = 120 / 30 or less Watts
Computer monitor - awake / asleep = 150 / 30 or less Watts
Laptop = 50 Watts
Radio (stereo) = 70 – 400 Watts
Refrigerator (frost-free, 16 cubic feet) = 725 Watts
19" television = 65–110 Watts
27" television = 113 Watts
36" television = 133 Watts
53"-61" Projection television = 170 Watts
Flat screen television = 120 Watts
Toaster = 800 – 1400 Watts
Toaster oven = 1225 Watts
VCR/DVD = 17–21 / 20–25 Watts
Vacuum cleaner = 1000 – 1440 Watts
Water heater (40 gallon) = 4500 – 5500 Watts
Water pump (deep well) = 250 – 1100 Watts
Water bed (with heater, no cover) = 120 – 380 Watts
Source: EERE
