09 elec 16
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Electricity is measured and purchased in units called kilowatt-hours, which are calculated by multiplying the power used by a device in kilowatts by the number of hours it is in use. The cost of electricity depends on the time of day, with peak hours being most expensive and off-peak hours being least expensive. Examples are provided to demonstrate how to calculate the kilowatt-hours and resulting cost for different electrical devices based on their power usage and duration of use.
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09 elec 16
- 1. Quantifying Electricity: Cost of Electricity
- 2. Cost of Electricity Electricity is purchased from the power company in units called kilowatt-hours (kW·h).
- 3. Cost of Electricity kW·h are found by multiplying the power used by a load (in kilowatts) by how long it has been on (in hours). 1 kW·h = (1 kW) (1 h)
- 4. Cost of Electricity In Toronto we pay different amounts for electricity depending on the time of day: Off-peak hours – least expensive Mid-peak hours – somewhat expensive Peak hours – most expensive
- 5. Try This. It took 4 hours for a 1200 W oven to cook a chicken. How many kW·h were consumed? 4.8 kW·h
- 6. Try This. How much would it cost to heat-up a frozen dinner in a 800 W microwave for 15 minutes if the cost of electricity is 7¢/kW·h? 1.4¢
- 7. Try This. If the cost of electricity is $0.05/kW·h, what would an office building pay to keep a 60 W light bulb at its entrance on all week? $0.50