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Rhys Carpenter Library

An Analysis of Return on Investment (ROI) and Carbon Footprint Reduction

Rhys Carpenter Library

Rhys Carpenter Library

After counting 916 light bulbs in Rhys Carpenter Library last Thursday, we complied the data and ran some analysis on three major types of bulbs. The two most widely used bulbs in this building are T8 and U-Shaped T8. As for the art exhibition, Carpenter Library uses PAR 38 for dimmable illumination. All three types have existing LED replacements. The replacements for T8 and PAR 38 are LED 6114 and LED 1666 respectively, and Jim McGaffin helped us acquire some detailed information on these two models. We've found one manufacturer that produces LED replacement for U-shaped T8, and unfortunately, without price information listed on their website. Therefore we approximately the price as $100 each.

The ROI is composed of two parts -- from energy savings and from labor cost savings of changing the bulbs as LED has an extended lifespan of approximately 50,000 hours.  The abbreviated formula for ROI is as follows:

ROI = Energy Savings/Year + Labor Cost Savings/Year - Cost (Material, Labor)

For complete ROI formula, breakdown of each section, and details on Carbon emission reduction calculations, please click here.

Carpenter Library

T8

U-shaped T8

PAR 38

Counts

527

226

50

Watts

32

32

100

Lifespan(hrs)

6,000

20,000

4,000

LED Replacement

LED 6114

LED-UTube

LED 1666

LED Price ($)

$85.75

$100

$82.15

Initial Investment (Labor & Material)

$49375.67

$24248.00

$4837.00

LED Watts

16

15

10

LED Lifespan(hrs)

50,000

50,000

50,000

Return on Energy Saving/Yr ($)

$3041.21

$1385.70

$1623.03

Return on Labor Cost/Yr ($)

$2951.20

$1265.60

$280.00

Total Return/Yr ($)

$5992.41

$2651.30

$1903.03

SmartIdeas Incentive ($)

$11857.50

$0.00

$750.00

Total Cost – Incentive ($)

$37518.17

$24248.00

$4087.00

Years to Breakeven

6.26

9.15

1.89

Carbon Emission Reduction/Yr (lbs)

4504.770353

2052.576814

2404.111313

The result from Carbon emission reduction is quite encouraging. With the high market price for LED technology, however, the ROI alone does not appear to be very promising.  It could turn out better if we take into account the incentives received from PECO's Smart Ideas Program.

If we replace all T8, U-Shaped T8 and PAR 38 in Carpenter, then about 7835.26 lbs of CO2 will be reduced each year, which is equivalent to 3.9 tons.

Follow this link for Carbon emission reduction calculations.

Carbon Emission Reduction

T8, U-shaped T8 & PAR38

Totals:

Reduction of CO2 (lbs):

8961.458479

Reduction of CO (lbs):

5.805676058

Reduction of NOx (lbs):

21.80139764

Reduction of SO2 (lbs):

89.4459552

Reduction of Particulates (lbs):

68.1263564

Posted in LED Project, Summer Research Journal.

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