How much will my
electrical bill be?
John Jones
Electricity is priced and sold by the
Kilowatt-hour. (kilo-1000)
If you use 1000 watts of electricity for 1
hour, you use 1 kwh
The price of a KwH of electricity is about 8
cents ($.08)
How does it add up?
If you run ten 100 watt light bulbs for
one hour:
10 * 100 – 1000 watts
1000 watts = 1 kwh
1*.08 = $.08 (8 cents)
How much does it cost?
Assume that you have three 300 watt
bulbs on the outside of your house.
You turn the lights on at 9:00 p.m.
and turn them off the next morning
at 7. How much does it cost to run
the bulbs through the night?
How long did the bulbs run? From 9 until 7
is 10 hours
How many total watts? 3*300 = 900 watts
Watthours = 10 hrs * 900 watts = 9,000
watthours
9000/1000 = 9 kwh * $.08 = $.72
Try this one!
A 5000 watt clothes dryer will dry a load of
clothes in 1 hour. How much does it cost
to dry the load of clothes?
5000 watts * 1 hr. = 5000 watthours
5000 watthours/1000 = 5 kilowatthours
5 kwh * .08 = $.40 (40 cents)
If you can do this one,
you’ve got it!!
A football field has 36 bulbs rated at
500 watts. The coach turns on the
lights at 5:00 p.m. and turns them
off after the game at 10:00 p.m.
How much does it costs to run the
lights during the game?
36 bulbs x 500 = 18000 watts
Time = 5 hours
18000*5=90000 watthours
90000/1000 = 90 kwh
900 * $.08 = $7.20