EGEE 102
Energy Conservation and Environmental Protection

Energy Use of Home Appliances, Page 2, Practice


What is the energy consumption of a refrigerator with a wattage rating of 700 Watts when it is operated for 24 hours a day?

Step 1

To solve, use the following formula:

Energy Consumption = Power Consumption x Number of Hours Operated


Energy Consumption = Watt/Hours (Wh) or KiloWatt/Hours (kWh)

Power Consumption = Watts (W) or kW (KiloWatts)

Number of Hours Operated = Hours (h)For the example above:

Energy Consumption = 700 W x 24 h

Energy Consumption = 16800 W/h

Step 2

To convert from W/h to kWh/h, remember that 1kWh/h = 1000 W/h

To solve, set up as a ratio and use linear algebra to solve for ?.

Steps for Conversion
1kWh 1000Wh = ?kWh 16800Wh
16,800Wh(1kWh) 1000Wh = ?KWh
16.8KWh = ?KWh

Practice Problem

Use the following link to generate a random practice problem.