The document compares the energy consumption and cost of using compact fluorescent light bulbs versus incandescent light bulbs over their lifetime. It finds that while compact fluorescent bulbs have a higher initial purchase price, they use less energy and last much longer. As a result, the energy and cost savings of compact fluorescent bulbs means they pay for themselves within a year or two of regular use. However, the document notes that compact fluorescent bulbs contain small amounts of mercury, which requires proper disposal procedures not readily available in the study location.

1. ENERGY CONSERVATION = FISCALLY CONSERVATIVE A COMPARISON OF COMPACT FLUORESCENT AND INCANDESCENT BULBS BY JONI JOHNSON, PETERSBURG MAT STUDENT

2. LIGHTING What type of light do you use in your home? How much do you spend on lighting in your home? If you could save, would you?

3. STUDY OBJECTIVES $$$$ = the fiscally conservative conservationist Having heard that compact fluorescent bulbs save energy, and having heard that they cost more money…

4. STUDY OBJECTIVES We set out to find The difference in kilowatt hour (kWh) consumption between the two bulbs The different in cost between the two bulbs When, and if, over the life of the two bulbs the compact fluorescent would be more cost effective than the incandescent bulbs

5. LIGHTING The typical household averages an estimated 25, 40-watt incandescent light bulbs* Therefore we selected 40-watt bulbs as our base for this study *(sampled from four integrated science students’ homes, so not representative)

6. STUDY METHODS To determine the difference in kWh consumption we: Searched the web to find a trustworthy source of Lumens Watts (W) Bulb lifespan in hours

7. STUDY METHODS To determine the difference in cost between the two bulbs we: Located the cheapest supplier for both bulb types Contacted the Petersburg Utility for current kWh rates

8. STUDY METHODS To determine when the compact fluorescent would be more cost effective than the incandescent bulb we: Combined the above two methods and calculated away…

9. LIGHTING RESULTS The 40-watt incandescent is slightly less bright than the 11-watt compact fluorescent 505 lumens compared to 660 lumens, respectively

10. LIGHTING RESULTS The 40-watt bulb has an estimated lifespan of 1000 hours The 11-watt compact fluorescent has an estimated lifespan of 15000 hours

11. RESULTS: CONSUMPTION KWH CONSUMPTION COMPARISON: per 1000 hours The 40W incandescent bulb consumes 40 kWh The 11W compact fluorescent bulb consumes 11 kWh

12. RESULTS: CONSUMPTION Extrapolated over the lifespan of the compact fluorescent bulb (15000 hours)…

13. RESULTS: CONSUMPTION Over the lifespan of the compact fluorescent bulb 15 incandescent bulbs have been used 600 kWh have been consumed by the incandescent bulb as opposed to 165 kWh by the compact fluorescent

14. RESULTS: COST COST $$$ The 40W incandescent bulb costs roughly $ 0.84/bulb The 11W compact fluorescent bulb costs roughly $2.19/bulb

15. RESULTS: COST With 15 incandescent bulbs lasting as long as 1 compact fluorescent… $0.84*15 = $12.60 As opposed to $2.10

16. RESULTS: COST FISCALLY SOUND Between two and three 40W incandescent bulbs expire and the compact fluorescent pays for itself

17. COST: ENERGY CONSUMPTION At the current 11.3 cents/kWh in Petersburg: Over 1000 hours A 40W incandescent costs $4.52 A 11W compact costs $1.24

18. COST: ENERGY CONSUMPTION With the purchase price of 0.84/bulb for the 40W incandescent 2.19/bulb for the 11W compact The cost per 1000 hours = $5.36 using the 40W incandescent $3.43 using the 11W compact

19. FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

20. FISCALLY AND ENVIRONMENTALLY CONSERVATIVE Back to our estimated 25 bulbs per household…

21. FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

22. FISCALLY AND ENVIRONMENTALLY CONSERVATIVE A household that currently uses 25, 40W incandescent bulbs Would save $932!!!! Over 10,000 hours of use If they used compact fluorescent bulbs

23. CONCLUSIONS In spite of the initial high purchase price Brighter compact fluorescent bulbs pay for themselves within one year

24. CONCLUSIONS - SO SIMPLE? If you do not leave a compact fluorescent bulb on for at least five minutes The lifespan decreases signficantly

25. CONCLUSIONS - SO SIMPLE? Compact fluorescent bulbs contain small amounts of mercury They need to be disposed of at the proper facility Such facility you’re not likely to encounter in Petersburg Hmmm… A dilemma.

26. references Jim Nelson, Petersburg Municipal Utility www.energystar.gov/index.cfm?c=cfls.pr_cfls http://energyhawk.com/lights/lights2.php