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Your Energy Savings  

This form helps you determine the dollar amount of energy savings you will realize if you substitute compact fluorescent bulbs for your regular incandescent bulbs in your house. Your fundraiser may not offer all of these bulbs, so this calculation will be approximate but it gives you an idea of what you can accomplish.

Note: When entering your cost per kilowatt Hour of electricity, you should use your highest rate to make this accurate. (some utilities use a sliding rate structure that charges you more if you use more.)

Your cost of energy per kilowatt hour
from your latest energy bill:
per kwh
A
B
C
D
E
F
G
H
I
J
Bulb
size
in
watts

Replaced by
bulb
size
watts

Number
of
bulbs
you
replace
Average
number
of hours
each bulb used
per day

Total
hours
on per
day
(C * D)

Total hours
on per Year
(365 * E)
Watts Saved
per bulb
(A - B)

Total Watts
saved per Year
(F * G)

Total Kilowatts
saved per
year
(H / 1000)

Total Cost Saved per Year
(I * your cost per kwh)

60-watt
13-watt
47
100-watt
23-watt
77
65-watt
15-watt
50
TOTAL YEARLY ENERGY SAVINGS
Should I replace my old bulbs now if they still work?
The answer may surprise you. From a purely energy savings and total cost savings, the answer is normally YES for several reasons:
  • The normal lifetime of an incandescent lightbulb is 1,000 hours. Assuming that your 100-watt bulb is brand new, it will consume 100 kilowatt hours until it burns out. At $.09/kwh, this will cost you at least $9.00 (it could be $25 or more depending on your utility rates.)
  • A replacement CFL bulb will cost you less than $5.00 and its energy usage during the same 1,000 hours will only cost you $2.07. Thus, you clearly come out ahead during the first 1,000 hours. After that, you will continue to spend only $2.07 for each 1000 hours of use as compared to the $9.00 you were spending. And you avoid the extra cost of $1.00 or so for a new incandescent bulb each 1000 hours.
You don't have to throw your old bulbs away. Most likely, you will not replace (nor should you) working bulbs in places of low usage like closets or rooms that are never used. Save your old bulbs to replace those bulbs when they burn out. When you have used up all your old bulbs, then you can buy new fluorescent bulbs.