Change a Light…
CHANGE THE
WORLD!
Energyis measured in kilowatt
hours (kWh)
and is determined by
Power (Watts) x Time
1000
One Light Bulb Per Student, One Hour
One “regular” light bulb (60 watt)
For every one student (95) for
one hour:
60 W x 95 hours
1000
5,700/1000 =
5.7 kWh
From the Department of Energy and
Environmental Protection Agency:
Pounds of Carbon Dioxide produced
by electricity source
1 kWh coal=2.123 pounds of CO2
1 kWh petroleum=1.943 pounds of CO2
1 kWh natural gas=1.255 pounds of
CO2
U. S. Average=1.35 pounds of CO2
One Light Bulb Per Student, One HOUR
60 Watt bulb:
CO2 produced:
5.7 x 1.35=
7.7 pounds of CO2
One Light Bulb Per Student, One HOUR
One CFL light bulb (13 watt)
For every one student (95) for one hour:
13 W x 95 hours
1000
1235/1000=
1.2 kWh
One Light Bulb Per Student, One HOUR
13 Watt CFL bulb:
CO2 produced:
1.2 x 1.35=
1.6 pounds of CO2
One Light Bulb Per Student, One HOUR
Savings in Carbon Dioxide:
7.7 lb - 1.6 lb =
6.1 pounds of CO2
One Light Bulb Per Student, One DAY
One regular light bulb (60 watt)
For every one student (95) for
four hours (per day):
60 W x 380 hours
1000
= 22800/1000
22.8 kWh
One Light Bulb Per Student, One DAY
60 Watt bulb:
CO2 produced:
22.8 x 1.35 =
30.8 pounds of CO2
One Light Bulb Per Student, One DAY
One CFL light bulb (13 watt)
For every one student (95) for
four hours (per day):
13 W x 380 hours
1000
= 4940/1000
4.9 kWh
One Light Bulb Per Student, One DAY
13 Watt bulb:
CO2 produced:
4.9 x 1.35=
6.6 pounds of CO2
One Light Bulb Per Student, One DAY
Savings in Carbon Dioxide:
30.8 lb – 6.6 lb =
24.2 pounds of CO2
One Light Bulb Per Student, One YEAR
One regular light bulb (60 watt)
For every one student (95) for
four hours (per day) for 365 days:
380 (one day) x 365 = 138700
60 W x 138700/1000
=8322 kWh
One Light Bulb Per Student, One YEAR
60 Watt bulb:
CO2 produced:
8322 x 1.35=
11,234.7 pounds of CO2
One Light Bulb Per Student, One YEAR
One CFL bulb (13 watt)
For every one student (95) for
four hours (per day) for 365 days:
380 (one day) x 365 = 138700
13 W x 138700/1000
=1803.1 kWh
One Light Bulb Per Student, One YEAR
13 Watt bulb:
CO2 produced:
1803.1 x 1.35=
2,434.2 pounds of CO2
One Light Bulb Per Student, One YEAR
Savings in Carbon Dioxide:
11234.7 lb – 2434.2 lb=
8,800.5
pounds of CO2 per year
One Light Bulb Per Student, One YEAR
60 Watt regular bulb:
Cost of Energy used
8322 kWh x 10 c/kWh
= 83220 cents ($832.20)
One Light Bulb Per Student, One YEAR
13 Watt CFL bulb:
Cost of Energy used
1803.1 kWh x 10 c/kWh
= 18031 cents ($180.31)
One Light Bulb Per Student, One YEAR
Savings in dollars:
$832.20-$180.31
= $651.89
One Light Bulb Per Student, One YEAR
$651.89 divided by 95 students
= $6.82 per student
How much did that 15 watt bulb
cost?...
And just so you know…
60 W = $1.72
Replaced every 1,500 hours
13 W = $4.99
Replaced every 8,000 hours
(5.3 times longer)
$1.72 x 5.3= $9.23
Now which one is more expensive?