ENERGY CONSERVATION = FISCALLY CONSERVATIVEENERGY CONSERVATION = FISCALLY CONSERVATIVE

A COMPARISON OF COMPACT FLUORESCENT AND INCANDESCENT

BULBS

BY JONI JOHNSON, PETERSBURG MAT STUDENT

A COMPARISON OF COMPACT FLUORESCENT AND INCANDESCENT

BULBS

BY JONI JOHNSON, PETERSBURG MAT STUDENT

LIGHTINGLIGHTING

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?

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?

STUDY OBJECTIVESSTUDY OBJECTIVES

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

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

STUDY OBJECTIVESSTUDY OBJECTIVES

We set out to find1. The difference in kilowatt hour (kWh)

consumption between the two bulbs

2. The different in cost between the two bulbs

3. When, and if, over the life of the two bulbs the compact fluorescent would be more cost effective than the incandescent bulbs

We set out to find1. The difference in kilowatt hour (kWh)

consumption between the two bulbs

2. The different in cost between the two bulbs

3. When, and if, over the life of the two bulbs the compact fluorescent would be more cost effective than the incandescent bulbs

LIGHTINGLIGHTING 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)

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)

STUDY METHODSSTUDY 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

To determine the difference in kWh consumption we: Searched the web to find a trustworthy source of

Lumens Watts (W) Bulb lifespan in hours

STUDY METHODSSTUDY 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

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

STUDY METHODSSTUDY 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…

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

LIGHTING RESULTSLIGHTING RESULTS

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

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

LIGHTING RESULTSLIGHTING RESULTS

The 40-watt bulb has an estimated lifespan of 1000 hours

The 11-watt compact fluorescent has an estimated lifespan of 15000 hours

The 40-watt bulb has an estimated lifespan of 1000 hours

The 11-watt compact fluorescent has an estimated lifespan of 15000 hours

RESULTS: CONSUMPTIONRESULTS: CONSUMPTION

KWH CONSUMPTION COMPARISON: per 1000 hours

The 40W incandescent bulb consumes 40 kWh

The 11W compact fluorescent bulb consumes 11 kWh

KWH CONSUMPTION COMPARISON: per 1000 hours

The 40W incandescent bulb consumes 40 kWh

The 11W compact fluorescent bulb consumes 11 kWh

RESULTS: CONSUMPTIONRESULTS: CONSUMPTION

Extrapolated over the lifespan of the compact fluorescent bulb (15000 hours)…

Extrapolated over the lifespan of the compact fluorescent bulb (15000 hours)…

Comparison of kWh consumption: compact fluorescent (cf) vs. incandescent

0

100

200

300

400

500

600

700

1 3 5 7 9 11 13 15

hours in 1000's

kWh

cf

incandescent

RESULTS: CONSUMPTIONRESULTS: 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

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

RESULTS: COSTRESULTS: COST

COST $$$ The 40W incandescent bulb costs roughly $ 0.84/bulb

The 11W compact fluorescent bulb costs roughly $2.19/bulb

COST $$$ The 40W incandescent bulb costs roughly $ 0.84/bulb

The 11W compact fluorescent bulb costs roughly $2.19/bulb

RESULTS: COSTRESULTS: COST

With 15 incandescent bulbs lasting as long as 1 compact fluorescent…

$0.84*15 = $12.60 As opposed to $2.10

With 15 incandescent bulbs lasting as long as 1 compact fluorescent…

$0.84*15 = $12.60 As opposed to $2.10

RESULTS: COSTRESULTS: COST

FISCALLY SOUND

Between two and three 40W incandescent bulbs expire and the compact fluorescent pays for itself

FISCALLY SOUND

Between two and three 40W incandescent bulbs expire and the compact fluorescent pays for itself

COST: ENERGY CONSUMPTIONCOST: 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

At the current 11.3 cents/kWh in Petersburg: Over 1000 hours

A 40W incandescent costs $4.52 A 11W compact costs $1.24

COST: ENERGY CONSUMPTIONCOST: 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

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

FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

Comparison of the cost to operate: compact fluorescent vs. incandescent

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10

time in 1000 increments (hours)

cost ($)

cf

incandescent

FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

Back to our estimated 25 bulbs per household…

Back to our estimated 25 bulbs per household…

FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

Comparison: cost of compact fluorescent vs. incandescent bulbs

0

200

400

600

800

1000

1200

1400

1 2 3 4 5 6 7 8 9 10

time in 1000's (hours)

cost ($)

cf

incandescent

FISCALLY AND ENVIRONMENTALLY CONSERVATIVE

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

A household that currently uses 25, 40W incandescent bulbs Would save

$932!!!!

Over 10,000 hours of use

If they used compact fluorescent bulbs

CONCLUSIONSCONCLUSIONS

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

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

CONCLUSIONS - SO SIMPLE?CONCLUSIONS - SO SIMPLE?

If you do not leave a compact fluorescent bulb on for at least five minutes

The lifespan decreases signficantly

If you do not leave a compact fluorescent bulb on for at least five minutes

The lifespan decreases signficantly

CONCLUSIONS - SO SIMPLE?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.

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.

referencesreferences

Jim Nelson, Petersburg Municipal Utility

www.energystar.gov/index.cfm?c=cfls.pr_cfls

http://energyhawk.com/lights/lights2.php

Jim Nelson, Petersburg Municipal Utility

www.energystar.gov/index.cfm?c=cfls.pr_cfls

http://energyhawk.com/lights/lights2.php